tilapia Bibliography based on merger of WOS with a Medline search of titles for 'tilapia' as of Jan.15, 2000
Abel, P. D., and Papoutsoglou, S. E. (1986). Lethal toxicity of cadmium to Cyprinus carpio and Tilapia aurea. Bull Environ Contam Toxicol 37, 382-6.
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Abo Hegab, S., and Hanke, W. (1984). The significance of cortisol for osmoregulation in carp (Cyprinus carpio) and tilapia (Sarotherodon mossambicus). Gen Comp Endocrinol 54, 409-17.
Changes in plasma cortisol and glucose concentration were studied in carp during acclimation from fresh water (FW) to 1.5% salt water and vice versa. There was an increase in cortisol and glucose concentration during acclimation from FW to salt water which lasted for several days. Reacclimation to FW did not cause clear changes in cortisol and glucose levels. One single injection of cortisol (0.2 mg/100 g or 1 mg/100 g) and additional transfer to salt water (1.5% for carp and 2.7% for tilapia) altered the changes caused by acclimation alone of cortisol, glucose, Na+ concentration, and the osmolality in plasma. Gill Na-K- ATPase activity was also influenced. The effects of cortisol on electrolyte concentrations during acclimation and on Na+-K+-ATPase activity differed in both types of fish. Cortisol clearly lowered the increase in plasma Na+ concentration of the stenohaline carp and increased the ATPase activity. The changes in plasma Na+ concentration of the euryhaline tilapia was not clearly altered and the enzyme activity was inhibited. The significance of these cortisol effects is discussed.
Agnese, J. F., Adepo-Gourene, B., Abban, E. K., and Fermon, Y. (1997). Genetic differentiation among natural populations of the Nile tilapia Oreochromis niloticus (Teleostei, cichlidae). Heredity 79, 88-96.
We analysed the genetic differentiation among 17 natural populations of the Nile tilapia Oreochromis niloticus (Linnaeus, 1758) using allozymes and restriction fragment length polymorphism (RFLP) of mitochondrial DNA (mtDNA). The populations studied, from the River Senegal to Lake Tana and from Lake Manzalla to Lake Baringo, represent all subspecies which have been previously described. Sixteen variable nuclear loci showed that these populations can be clustered in three groups: (1) West African populations (Senegal, Niger, Volta and Chad drainages), (2) Ethiopian Rift Valley populations (Lakes Awasa, Ziway, Koka and the Awash River) and (3) Nile drainage (Manzalla, Cairo, Lake Edward) and Kenyan Rift Valley populations (Lakes Turkana, Baringo and River Suguta). Nine different mtDNA haplotypes were found in the RFLP analysis of a 1 kb portion of the D-loop region. The network obtained showed that there are three geographically distinct groups; all West African populations and O. aureus are clustered, the two Ethiopian Rift Valley populations are distinct and between these two groups are the Kenyan and Ugandan Rift Valley populations. Nile populations show affinities both with West African populations and with specimens from Lakes Tana and Turkana. Taxonomic and biogeographical implications of these results are discussed.
Agnese, J. F., Adepo-Gourene, B., Owino, J., Pouyaud, L., and Aman, R. (1999). Genetic characterization of a pure relict population of Oreochromis esculentus, an endangered tilapia. Journal of Fish Biology 54, 1119-1123.
Genetic variation of the Oreochromis esculentus population from Lake Kanyaboli was studied using 24 allozyme loci and three microsatellite loci and compared with four populations of O. niloticus. Results strongly suggest that this population can be considered as pure. (C) 1999 The Fisheries Society of the British Isles.
Al Hafedh, Y. S. (1999). Effects of dietary protein on growth and body composition of Nile tilapia, Oreochromis niloticus L. Aquaculture Research 30, 385-393.
The effects of dietary protein (25%, 30%, 35%, 40% and 45%) on growth, survival, feed conversion ratio (FCR), protein efficiency ratio (PER) and body composition were investigated for four sizes (0.51, 45, 96 and 264 g) of Nile tilapia, Oreochromis niloticus L. In all four experiments, there was a progressive increase in growth with increasing dietary protein. In fry (0.51 g), significantly higher growth, survival and feed conversion were recorded for fish fed 40-45% rather than 25-35% protein diets. Similar trends for growth and FCR were also noted in 45 g fish. For larger (96 and 264 g) tilapia, significant differences in growth and FCR were found only between fish fed 25% and 30-45% protein diets. FCR and PER decreased with increasing weight of fish, and both were found to be negatively correlated with dietary protein level. Whole- body composition of the smallest fish was significantly influenced by dietary protein content. Percentage body protein of the fish fed 40-45% protein was higher than that of fish fed 25-35% protein diets, whereas lipid content decreased with increasing dietary protein level. In 45 g fish, both protein and lipid contents were higher in fish fed 25% and 30% protein diets than in those fed 35-45% protein diets. In larger tilapia, no significant influence of dietary protein level on body protein content was found. Percentage lipid decreased with increasing dietary protein level, and no definite trends in ash content were found. The results of these studies indicate that O. niloticus fry (0.51 g) should be reared on a practical diet containing 40% protein, and larger tilapia (96-264 g) on a diet containing 30% protein.
Alam, M. S., Lavender, F. L., Iyengar, A., Rahman, M. A., Ayad, H. H., Lathe, R., Morley, S. D., and Maclean, N. (1996). Comparison of the activity of carp and rat beta-actin gene regulatory sequences in tilapia and rainbow trout embryos. Mol Reprod Dev 45, 117-22.
A comparative study on the level of expression of lacZ reporter constructs driven by equivalent carp and rat beta-actin regulatory sequences was carried out in embryos of tilapia and rainbow trout. DNA was microinjected into fertilised tilapia and rainbow trout eggs and the embryos/fry were assayed at various developmental stages for beta- galactosidase expression. We provide evidence to demonstrate that the carp beta-actin promoter/ lacZ reporter gene is expressed at higher levels than the equivalent rat beta-actin construct in both species.
Allen, P. (1994). Distribution of mercury in the soft tissues of the blue tilapia Oreochromis aureus (Steindachner) after acute exposure to mercury (II) chloride. Bull Environ Contam Toxicol 53, 675-83.
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Allen, P. (1995). Soft-tissue accumulation of lead in the blue tilapia, Oreochromis aureus (Steindachner), and the modifying effects of cadmium and mercury. Biol Trace Elem Res 50, 193-208.
The interaction of mercury and cadmium with lead was investigated by exposing Oreochromis aureus to two heavy metals simultaneously. The chronic accumulation profile of lead was determined by analyzing the liver, brain, gill filaments, intestine, caudal muscle, spleen, trunk kidney, and gonads following exposure to lead alone and in mixtures with mercury and cadmium. Nominal exposure concentrations of lead were 0.05, 0.10, 0.50, and 1.00 mg/L. Mixtures of lead (0.50 or 0.05 mg/L) with cadmium (0.05 mg/L) and lead (0.50 or 0.05 mg/L) with mercury (0.05 mg/L) were also used. Following 140 d of exposure to lead, the highest concentrations of lead consistently accumulated in the trunk kidney. The concentration of lead in the kidney was decreased by coexposure to mercury or cadmium, but increased in the muscle and liver. Under all exposure regimes, the median concentration of lead in the muscle exceeded safety levels recommended for human consumption. In a food fish, such as O. aureus, a knowledge of toxic metal accumulation patterns is of great importance.
Alsop, D. H., Kieffer, J. D., and Wood, C. M. (1999). The effects of temperature and swimming speed on instantaneous fuel use and nitrogenous waste excretion of the Nile tilapia. Physiol Biochem Zool 72, 474-83.
The effects of acclimation temperature (30 degrees, 20 degrees, and 15 degrees C) and swimming speed on the aerobic fuel use of the Nile tilapia (Oreochromis niloticus; 8-10 g, 8-9-cm fork length) were investigated using a respirometric approach. As acclimation temperature was decreased from 30 degrees C to 15 degrees C, resting oxygen consumption (MO2) and carbon dioxide excretion (MCO2+) decreased approximately twofold, while nitrogenous waste excretion (ammonia-N plus urea-N) decreased approximately fourfold. Instantaneous aerobic fuel usage was calculated from respiratory gas exchange. At 30 degrees C, resting MO2 was fueled by 42% lipids, 27% carbohydrates, and 31% protein. At 15 degrees C, lipid use decreased to 21%, carbohydrate use increased greatly to 63%, and protein use decreased to 16%. These patterns at 30 degrees C and 15 degrees C in tilapia paralleled fuel use previously reported in rainbow trout acclimated to 15 degrees C and 5 degrees C, respectively. Temperature also had a pronounced effect on critical swimming speed (UCrit). Tilapia acclimated to 30 degrees C had a UCrit of 5.63+/-0. 06 body lengths/s (BL/s), while, at 20 degrees C, UCrit was significantly lower at 4.21+/-0.14 BL/s. Tilapia acclimated to 15 degrees C were unable or unwilling to swim. As tilapia swam at greater speeds, MO2 increased exponentially; MO2min and MO2max were 5.8+/-0.6 and 21.2+/-1.5 micromol O2/g/h, respectively. Nitrogenous waste excretion increased to a lesser extent with swimming speed. At 30 degrees C, instantaneous protein use while swimming at 15 cm/s ( approximately 1.7 BL/s) was 23%, and at UCrit (5.6 BL/s), protein use dropped slightly to 17%. During a 48-h swim at 25 cm/s (2.7 BL/s, approximately 50% UCrit), MO2 and urea excretion remained unchanged, while ammonia excretion more than doubled by 24 h and remained elevated 24 h later. These results revealed a shift to greater reliance on protein as an aerobic fuel during prolonged swimming.
Alvarenga, C. M., and Volpato, G. L. (1995). Agonistic profile and metabolism in alevins of the Nile tilapia. Physiol Behav 57, 75-80.
Metabolic differences derived from social stress usually show data with high variance that may hinder the finding of important differences. Since such high variance may be caused by agonistic variability occurring during social interactions, this work tested whether metabolism is associated with agonistic profile in the cichlid fish Nile tilapia, Oreochromis niloticus (L.). Metabolism was inferred from oxygen consumption, resistance to progressive hypoxia and ventilatory rate. Fifteen pairs of alevins were used for each metabolic and behavioral series. An ethogram based on 8 types of agonistic interactions was employed. Agonistic profiles were determined and associated with the physiological parameters later on. The test of canonical correlation showed significant association between some agonistic profiles and metabolism. Ventral nipping and lateral fight appeared as the two most important in promoting association with metabolism.
Alves, M. M., Leme Dos Santos, H. S., Lopes, R. A., Petenusci, S. O., and Haiyashi, C. (1983). Rhythm of development in the oocyte of the tilapia Oreochromis niloticus L. (Pisces: Cichlidae); a morphometric and histochemical study. Gegenbaurs Morphol Jahrb 129, 575-92.
The ovary of the tilapia Oreochromis niloticus was studied morphologically and morphometrically; the zonas granulosa and radiata, the ooplasm and the yolk globules were studied histochemically. The ovary is of typical teleostean type consisting of a wall and developing oocytes. The development of oocytes has been divided into 10 cytological stages. Histochemically the zona radiata and yolk globules contain glycoprotein (neutral mucopolysaccharides and protein radicals alpha-amino groups, cystine, cystein, tyrosin, tryptophane, and arginine. The zona granulosa and ooplasm contain neutral and carboxylate acid mucopolysaccharides and protein radicals alpha-amino group, cystein, cystine, tyrosin, arginine, and tryptophane.
Amin, N. E., Abdallah, I. S., Faisal, M., Easa, M. e.-S., Alaway, T., and Alyan, S. A. (1988). Columnaris infection among cultured Nile tilapia Oreochromis niloticus. Antonie Van Leeuwenhoek 54, 509-20.
Flexibacter columnaris was isolated from 13 cultured Oreochromis niloticus showing respiratory disorders. The isolates developed typical swarming rhizoid colonies on Cytophaga agar medium. Antibiotic sensitivity test revealed the susceptibility of F. columnaris isolated to oxytetracycline, chloramphenicol and erythromycin. A marked difference in the pathogenicity of seven tested isolates was observed: two were highly virulent, one was moderately virulent and four were avirulent. No experimental infection could be induced with the highly virulent isolates except after injuring one of the natural barriers of the fish body. The severity of the disease and the increased median death time shortened by keeping infected fishes with injured gills in water containing ammonia. In naturally infected O. niloticus, the disease became chronic as indicated by the presence of excessive proliferative and necrotic changes. On the other hand, severe dilatation of branchial blood vessel, oedema and round cell infiltration proved that, the disease among experimentally infected tilapias was acute.
Ananthakrishnan, K. R., and Kutty, M. N. (1974). Mortality & breathing rate at high ambient temperatures in the cichlid fish, Tilapia mossambica Peters. Indian J Exp Biol 12, 55-9.
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Anderson, J., Capper, B. S., and Bromage, N. R. (1991). Measurement and prediction of digestible energy values in feedstuffs for the herbivorous fish tilapia (Oreochromis niloticus Linn.). Br J Nutr 66, 37-48.
Digestible energy (DE) values were measured in a selection of feedstuffs for the tilapia (Oreochromis niloticus Linn.) and used to develop equations for predicting DE values of a wider range of feedstuffs from chemical analyses. Preliminary work examined the influences of substitution level in a reference diet and adaptation over time on DE values for soya-bean meal. Length of adaptation period significantly affected DE values (P less than 0.01), but substitution level, over the range 200-600 g soya-bean meal/kg reference diet, did not. The DE values of sixteen feedstuffs, thirteen derived from plant sources and three animal by-products, were subsequently determined. DE values for plant-derived feedstuffs were found to be higher than those quoted in the literature for trout (Oncorhynchus mykiss) and catfish (Ictalurus punctatus), whereas DE values for animal-derived feedstuffs were lower than those for trout and pigs. It was concluded that energy values quoted in tables of feed composition for other species are inaccurate when used as proxy values for tilapia. Regression equations were therefore computed using data from the present study to provide a rapid means of predicting DE values of feedstuffs for tilapia. Equations using neutral-detergent fibre as an independent variable were found to predict DE values of plant-derived feedstuffs reliably. Where fibre values were not used as independent variables, available carbohydrate and crude protein (nitrogen x 6.25) were found to be useful predictors of DE values. These equations offer the possibility of reducing the need for time-consuming digestibility trials with tilapia when formulating least-cost production diets for this species.
Andrade, R. M. d., and Antunes, C. M. (1969). [Biological control: Tilapia melanopleura Dumeril versus Biomphalaria glabrata (Say), under laboratory conditions]. Rev Bras Malariol Doencas Trop 21, 49-58.
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Anjum, F., and Qadri, S. S. (1986). In vivo metabolism of fenitrothion (0,0-dimethyl-0-(4-nitro-m-tolyl) phosphorothioate) in fresh water teleost (Tilapia mossambica). Bull Environ Contam Toxicol 36, 140-5.
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Annett, C. A., Pierotti, R., and Baylis, J. R. (1999). Male and female parental roles in the monogamous cichlid, Tilapia mariae, introduced in Florida. Environmental Biology of Fishes 54, 283-293.
We documented male and female parental roles of a monogamous fish, the spotted tilapia, Tilapia mariae, in channelized rivers in southern Florida, where this species dominated the fish fauna within 10 years of their introduction. Clearly differentiated parental roles existed between males and females, with females performing nearly all tending of embryos and most tending of free embryos. After young became free- swimming and left the nest, however, males took over primary tending of the school of young while the female patrolled the perimeter of the school and performed nearly all chases directed at predators. Male and female T. marine also traded off vigilance and feeding, and showed a high degree of intrapair coordination. Experimental removal of one or both parents had major effects on parental behavior and brood survival and integrity. Solitary females took on a parental role intermediate between that of the male and female of a pair. Untended broods were attacked by predators and scattered into aquatic vegetation, and were not observed to reform. Under dense nesting conditions we observed adoption of broods, group rearing of free-swimming young and the presence of non-breeder 'satellites' sharing and defending a territory with breeders. This highly complex parental care may have allowed T. mariae to invade fish communities dominated by uniparental centrarchids, as well as allowing them to use disturbed habitats such as channelized rivers that are of poor quality for nesting and rearing offspring.
Apfelbach, R. (1969). Correlation analyses of behaviour patterns in Tilapia (Pisces, Cichlidae). Naturwissenschaften 56, 335.
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Arnold, M., Kriesten, K., and Peters, H. M. (1968). [The prehensile organs of Tilapia larvae (Cichlidae, Teleostei). Histochemical and electron microscopic studies]. Z Zellforsch Mikrosk Anat 91, 248-60.
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Auperin, B., Rentier-Delrue, F., Martial, J. A., and Prunet, P. (1994). Characterization of a single prolactin (PRL) receptor in tilapia (Oreochromis niloticus) which binds both PRLI and PRLII. J Mol Endocrinol 13, 241-51.
In tilapia, there are two forms of prolactin (PRL) whose effects on sodium and chloride movements differ and depend on the living environment of the fish. To see whether different receptors or the same receptor mediates these different effects, we have characterized the specific binding of both forms of tilapia (ti)PRL in two osmoregulatory organs, the gill and kidney. Two recombinant tiPRLs were used for this analysis. The recombinant hormones had the same properties as the native hormones in a tilapia gill radioreceptor assay. Specific binding to gill and kidney membranes was increased by optimizing the quality of the tissue preparations (physiological state of fish, membrane preparation) and the incubation conditions (pH, salt concentrations, temperature, time). Under these optimized conditions, we detected only one class of high affinity PRL receptor in gill and kidney. Its binding affinity was higher for tiPRLI than for tiPRLII in both gill and kidney (for tiPRLI the respective affinity values were 2.9 and 2.3 x 10(10) per M, for tiPRLII they were 1.9 and 0.5 x 10(10) per M). In competition studies, tiPRLI was more potent, followed by tiPRLII and ovine (o)PRL. tiGH and oGH did not significantly displace either tiPRL. The receptor we have characterized thus recognizes quite specifically both tiPRLs.
Auperin, B., Rentier-Delrue, F., Martial, J. A., and Prunet, P. (1994). Evidence that two tilapia (Oreochromis niloticus) prolactins have different osmoregulatory functions during adaptation to a hyperosmotic environment. J Mol Endocrinol 12, 13-24.
Two forms of prolactin (tiPRLI and tiPRLII), with only 69% sequence identity, have been previously described in the cichlid fish tilapia (Oreochromis species). In the present study we have attempted to investigate the biological activity of these two prolactin forms during adaptation to a hyperosmotic environment. For this purpose, we have developed two highly sensitive (sensitivity: 0.05 ng/ml) and specific (cross-reactivity 0.04%) radioimmunoassays for tiPRLI and tiPRLII, using recombinant hormones. When fish were directly transferred from fresh to brackish water, the measured levels of plasma tiPRLI and tiPRLII dropped abruptly until 12 h after transfer. Thereafter, plasma tiPRLII remained stable (around 0.5 ng/ml) until the end of the experiment, whereas plasma tiPRLI continued to decrease to undetectable levels. These different patterns of change are reflected in the calculated ratio of plasma tiPRLII to tiPRLI, which increased from 2-3 in fresh water-adapted fish to over 10 in fish which had spent 3 days or more in brackish water. The pituitary contents of tiPRLI and tiPRLII varied in a qualitatively similar fashion after transfer to brackish water. The tiPRLI content dropped continuously after 12 h, reaching one- twelfth of its initial level after 2 weeks. The pituitary tiPRLII content, on the other hand, did not decrease significantly until day 7, and after a 2-week exposure to brackish water it had only decreased by 50%. When injected into tilapia adapted to brackish water, both ovine prolactin and recombinant tiPRLI induced a clear dose-dependent ion- retaining effect. In contrast, the effect induced by tiPRLII treatment was markedly smaller and not dose-dependent. Northern blot analysis of tiPRL mRNAs using either a tiPRLI or a tiPRLII cDNA probe indicated the presence of two mRNAs differing in size: a 1.7 kb mRNA coding for tiPRLI and a 1.3 kb mRNA coding for tiPRLII. After transfer to brackish water, levels of the two mRNAs decreased similarly. The present study indicates that, in O. niloticus, the two forms of prolactin have different osmoregulatory roles during adaptation to brackish water. Accordingly, their synthesis are differentially regulated after transfer to a hyperosmotic environment, presumably at a post- transcriptional level.
Auperin, B., Rentier-Delrue, F., Martial, J. A., and Prunet, P. (1995). Regulation of gill prolactin receptors in tilapia (Oreochromis niloticus) after a change in salinity or hypophysectomy. J Endocrinol 145, 213-20.
Prolactin (PRL) receptors in gill tissue have been analyzed in tilapia (Oreochromis niloticus) after transfer from fresh water (FW) to brackish water (BW). This study has indicated the presence of only one class of tilapia PRL (tiPRL) receptor whatever the salinity. After transfer, however, the percentage of specific binding of the two forms of tiPRL (tiPRLI and tiPRLII) increased significantly. Scatchard analysis of tiPRLI binding indicated an increase in receptor affinity, an effect which was not accompanied by any change in receptor specificity. Transfer to BW also caused the number of tiPRL receptors to increase rapidly, remaining high in fish adapted to BW for 28 days. Based on the sharp reduction in plasma tiPRLI and tiPRLII levels after transfer to BW, one possible explanation may be that tiPRL itself is an important factor regulating the number of free receptors. This hypothesis finds support in the fact that the number of tiPRL receptors also increased in hypophysectomized fish reared in FW. However, the absence of change in receptor affinity after hypophysectomy suggested that yet other factors are involved in tiPRL receptor regulation during the transfer from FW to BW. The paradoxically high numbers of tiPRL receptors in the gills of BW-adapted tilapia, even though PRL is known to be a FW-adapting hormone, is discussed with regard to the environment in which tilapia live.
Auperin, B., Leguen, I., Rentier-Delrue, F., Smal, J., and Prunet, P. (1995). Absence of a tiGH effect on adaptability to brackish water in tilapia (Oreochromis niloticus). Gen Comp Endocrinol 97, 145-59.
The aim of this study was to investigate the possible role of growth hormone in the adaptation of tilapia (Oreochromis niloticus) to brackish water and to analyze its interactions with prolactin in this process. Plasma levels of growth hormone do not change upon transfer to brackish water. Treatment of intact tilapia in fresh water with growth hormone prior to transfer did not enable the fish to preadapt to brackish water: the duration of the hydromineral imbalance after transfer was the same in treated animals and controls. The major osmoregulatory role of prolactin in fresh water led us to test the hypothesis that prolactin might antagonize the effect of growth hormone on adaptation to brackish water. Growth-hormone-treated hypophysectomized animals, however, exhibited no increased osmoregulatory capacity as compared to hypophysectomized controls, confirming the absence of a growth-hormone-related osmoregulatory effect. When prolactin and growth hormone were coinjected, growth hormone also proved unable to oppose the Na+ retaining effect of prolactin, in both brackish and fresh water. Surprisingly, hypophysectomized animals adapt better to brackish water than do sham- operated animals. This result is discussed in light of the effects of prolactin and cortisol on osmoregulation in brackish water and we suggest that an important event which allows O. niloticus to adapt to hyperosmotic environment is the reduction of plasma PRL upon transfer to brackish water.
Auperin, B., Baroiller, J. F., Ricordel, M. J., Fostier, A., and Prunet, P. (1997). Effect of confinement stress on circulating levels of growth hormone and two prolactins in freshwater-adapted tilapia (Oreochromis niloticus). Gen Comp Endocrinol 108, 35-44.
The aim of the present study was to assess a potential link between confinement stress and prolactin (PRL), the hormone responsible for adaptation to a hypoosmotic environment in freshwater-adapted tilapia (Oreochromis niloticus). The effect of stress on plasma levels of the two tilapia PRL forms, tiPRLI (or tiPRL188) and tiPRLII (or tiPRL177), was examined along with the effects on plasma levels of cortisol and growth hormone (GH). In a preliminary study, various sampling protocols (immediate sampling; sampling one by one; anesthesia at 0.5, 1, 2 ml/liter phenoxyethanol) were tested for their ability to modify basal plasma PRL and cortisol. In fish sampled within 1 min of capture (immediate sampling), no changes in the plasma levels of these hormones were observed, whereas when fish were sampled one at a time, PRL levels did not change but cortisol levels were modified. The immediate sampling protocol was used to study the effects of 1 hr confinement stress, which induced a large increase in plasma cortisol levels as well as increases tiPRLI and tiPRLII levels with kinetics similar to those of cortisol. In contrast, plasma tiGH levels significantly decreased after 1 hr confinement. When this stress situation was removed, plasma cortisol and tiPRL levels decreased and plasma GH levels increased. Two and one-half hours later, values were not significantly different from those measured in control fish. In tilapia exposed to 24 hr confinement stress, similar changes in hormone levels were observed. However, after 24 hr confinement, only cortisol levels were significantly different from those measured in control fish. None of these stress conditions significantly changed plasma chloride levels. Together, these results indicate that both PRL and GH have important roles in the adaptive response of freshwater-adapted tilapia to confinement stress. Copyright 1997 Academic Press.
Ay, O., Kalay, M., Tamer, L., and Canli, M. (1999). Copper and lead accumulation in tissues of a freshwater fish Tilapia zillii and its effects on the branchial Na,K-ATPase activity. Bull Environ Contam Toxicol 62, 160-8.
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Ayson, F. G., Kaneko, T., Tagawa, M., Hasegawa, S., Grau, E. G., Nishioka, R. S., King, D. S., Bern, H. A., and Hirano, T. (1993). Effects of acclimation to hypertonic environment on plasma and pituitary levels of two prolactins and growth hormone in two species of tilapia, Oreochromis mossambicus and Oreochromis niloticus. Gen Comp Endocrinol 89, 138-48.
Specific radioimmunoassays (RIAs) for the pair of tilapia prolactins (tPRLs) and growth hormone (tGH) were developed using antisera raised in rabbits. Anti-tPRL177 did not cross-react with tPRL188 and tGH. Anti- tPRL188 did not cross-react with tPRL177 and showed slight cross- reaction (3.1%) with tGH. Anti-tGH showed negligible cross-reactions with tPRL177 (0.4%) and tPRL188 (1.6%). Pituitary homogenates and plasma from Oreochromis niloticus exhibited displacement curves parallel to the standards in the three RIAs. Plasma from hypophysectomized O. niloticus showed no cross-reaction in any of the three RIAs. Plasma and pituitary levels of the two PRLs in O. mossambicus in freshwater did not differ significantly from each other, whereas in O. niloticus, the levels of PRL177 were significantly greater than those of PRL188 in both plasma and pituitary. After acclimation for 3-4 weeks in seawater (O. mossambicus) or 50% seawater (O. niloticus), the levels of both PRLs decreased significantly compared to their levels in freshwater. Acclimation to a hypertonic environment did not affect plasma and pituitary GH levels in either species. Immunocytochemical staining of the pituitary of O. niloticus revealed colocalization of both PRLs in rostral pars distalis. Our findings suggest that the synthesis and secretion of the two tPRLs could be independently regulated in the same cells.
Ayson, F. G., Kaneko, T., Hasegawa, S., and Hirano, T. (1994). Differential expression of two prolactin and growth hormone genes during early development of tilapia (Oreochromis mossambicus) in fresh water and seawater: implications for possible involvement in osmoregulation during early life stages. Gen Comp Endocrinol 95, 143-52.
The possible involvement of prolactin (PRL) and growth hormone (GH) in osmoregulation during early life stages of the tilapia (Oreochromis mossambicus) was examined by in situ hybridization and immunocytochemistry using synthetic oligonucleotide probes and homologous antisera to two tilapia PRLs (PRL188 and PRL177) and GH. Hybridization signals for PRL188 mRNA were detected for the first time in newly hatched larvae (5 days after fertilization), and were significantly greater in larvae in fresh water (FW) than those in seawater (SW) until 10 days after hatching. PRL177 mRNA was detected in the pituitary of embryos 1 day before hatching. Although PRL177 gene expression in the embryo and newly hatched larvae in FW was not significantly different from those in SW, the expression was significantly greater in FW than in SW from Day 2 until Day 10. Hybridization signals for GH mRNA were first detected in newly hatched larvae. No significant differences in GH mRNA expression were observed between larvae in FW and those in SW. A stronger immunoreaction, a significantly larger PRL cell size, and a pituitary area containing PRL cells were observed in larvae hatched and maintained in FW, in those transferred from SW to FW, compared to larvae hatched and maintained in SW, and in those transferred from FW to SW. No significant difference was observed in the activity of GH cells between larvae in FW and those in SW. These results suggest that both PRLs are involved importantly in FW adaptation, whereas GH does not seem to play a critical role in osmoregulation during early stages of tilapia.
Baker, D. A., and Smitherman, R. O. (1983). Immune response of Tilapia aurea exposed to Salmonella typhimurium. Appl Environ Microbiol 46, 28-31.
Tilapia aurea showed a specific immune response to Salmonella typhimurium. S. typhimurium was introduced into the gut of T. aurea by force-feeding. S. typhimurium was isolated from the fish viscera after 15 days, but at 30 days viable cells were not detected. T. aurea had an antibody titer to S. typhimurium after 30 days which was fivefold greater than the natural background antibody titer. An elevated antibody titer was not indicative of active bacterial infection.
Baker, D. A., Smitherman, R. O., and McCaskey, T. A. (1983). Longevity of Salmonella typhimurium in Tilapia aurea and water from pools fertilized with swine waste. Appl Environ Microbiol 45, 1548-54.
Salmonella typhimurium declined rapidly when inoculated into Tilapia aurea culture pools fertilized with fresh swine waste. Within the water column, a 95% decline of viable cells occurred during the first 6 h. Isolation of viable salmonellae was possible at 16 days post- inoculation, but not at 32 days. Similarly, salmonellae could be detected in the viscera and epithelium of T. aurea at 16 days, although not at 32 days. Salmonellae were not isolated from the fish flesh, nor was there evidence of septicemic infection.
Balavenkatasubbaiah, M., Rani, A. U., Geethanjali, K., Purushotham, K. R., and Ramamurthi, R. (1984). Effect of cupric chloride on oxidative metabolism in the freshwater teleost, Tilapia mossambica. Ecotoxicol Environ Saf 8, 289-93.
The freshwater teleost Tilapia mossambica was subjected to lethal (6.0 mg X liter-1 = LC50/48 hr) and sublethal (1.5 mg X liter-1 copper treatment for 1, 7, and 14 days. The whole animal oxygen consumption and the activity levels of succinate dehydrogenase and lactate dehydrogenase in liver and muscle were studied. The decrease in oxygen consumption and succinate dehydrogenase activity and significant increase in lactate dehydrogenase activity suggest that the stressed fish is meeting its energy requirements through anaerobic oxidation and these enzymes can be used as indicators in monitoring metal-induced toxicity in fish.
Balm, P. H., Groneveld, D., Lamers, A. E., and Wendelaar Bonga, S. E. (1993). Multiple actions of melanotropic peptides in the teleost Oreochromis mossambicus (tilapia). Ann N Y Acad Sci 680, 448-50.
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Balm, P. H., Pepels, P., Helfrich, S., Hovens, M. L., and Bonga, S. E. (1994). Adrenocorticotropic hormone in relation to interrenal function during stress in tilapia (Oreochromis mossambicus). Gen Comp Endocrinol 96, 347-60.
This study examines ACTH-like immunoreactivity in the pituitary pars distalis and pars intermedia of the freshwater teleost Oreochromis mossambicus (tilapia). Two products (tACTHA and tACTHB) were present in both lobes. These two products also accounted for the majority of the ACTH i.r. when in vitro pars distalis incubation medium was analyzed by HPLC. In a homologous bioassay the two tilapia ACTH-like molecules and human ACTH1-39 possessed similar corticotropic potency. The peptides were quantified using a newly validated radioimmunoassay, which was also used to measure ACTH in plasma of unstressed and stressed fish. Short-term ( 12 min) stress rapidly increased plasma cortisol, reaching levels of around 300 ng/ml in 5 min. Surprisingly, this initial elevation was not accompanied by a rise in plasma ACTH levels. A more prolonged (3 hr) confinement in pairs resulted in high plasma cortisol and ACTH levels in one fish of every pair. The second fish had control ACTH levels and only marginally elevated cortisol levels. Therefore, in this species social interactions seem to influence the reaction of the pituitary-interrenal axis to stress. The short-term cortisol response to disturbance could be abolished completely by pretreating fish in vivo with cortisol for 48 hr. This treatment did not alter circulating ACTH levels. It is concluded that tilapia did not rely on circulating ACTH for a rapid elevation of plasma cortisol levels. Both neuronal mechanisms and cortisol feedback may regulate the pituitary-interrenal axis at the level of the interrenal.
Balm, P. H., Hovens, M. L., and Wendelaar Bonga, S. E. (1995). Endorphin and MSH in concert form the corticotropic principle released by tilapia (Oreochromis mossambicus; Teleostei) melanotropes. Peptides 16, 463-9.
HPLC characterization of tilapia pituitary endorphins using an antibody specific for N-terminally acetylated endorphins yielded three major peaks in the neurointermediate lobe, but none in the pars distalis. The melanotropes secreted two of the immunoreactive products in vitro, one of which coeluted with Xenopus laevis N-ac-beta-END(1-8). This immunoreactive fraction also coeluted with diacetyl-alpha-MSH. Evidence is presented that the noteworthy corticotropic potency of this HPLC fraction, previously attributed to diacetyl-alpha-MSH, results from END and MSH acting in a coordinated fashion. Confinement stress had no effect on plasma N-ac-beta-END immunoreactivity, but led to a decrease in plasma alpha-MSH levels. Therefore, it seems unlikely that the corticotropic action of the peptides regulates the elevation of cortisol production that takes place during confinement, but it may play a role during other forms of stress that are known to activate the melanotropes.
Balm, P. H., van Lieshout, E., Lokate, J., and Wendelaar Bonga, S. E. (1995). Bacterial lipopolysaccharide (LPS) and interleukin 1 (IL-1) exert multiple physiological effects in the tilapia Oreochromis mossambicus (Teleostei). J Comp Physiol [B] 165, 85-92.
To gain insight in immuno-endocrine communication in teleosts the physiological effects of interleukin 1 and bacterial lipopolysaccharide in teleosts were investigated. Tilapia (Oreochromis mossambicus) were treated with murine interleukin 1 and E. coli lipopolysaccharide in vivo, and lipopolysaccharide was administered to pituitary lobes and head kidneys in vitro. The integument of the fish appeared to be a sensitive target for the preparations tested, since proliferation of chloride cells and of epidermal mucous cells was observed as well as an increase in epidermal thickness. These effects may relate to an acute phase-like reaction caused by the treatments. Lipopolysaccharide administration furthermore resulted in an increase in plasma free fatty acids levels. Lipopolysaccharide, but not interleukin 1, stimulated the interrenal axis of the fish, as judged by the increase in cortisol production measured in superfusion of head kidneys. In addition to these in vivo effects, lipopolysaccharide also displayed several effects in vitro. Pituitary adrenocorticotropic hormone, as well as alpha-melanocyte stimulating hormone, release was inhibited, and the head kidney responsiveness to adrenocorticotropic hormone was inhibited after pretreatment of the tissue with the E. coli product. This latter effect coincided with the release of an unidentified alpha-melanocyte stimulating hormone immunoreactive fraction by the head kidneys which could be stimulated by lipopolysaccharide. The data strongly support the notion that the immune system is involved in adaptive regulations in teleosts, and that immunoendocrine interactions are phylogenetically old mechanisms.
Balthazart, J. (1974). [Non-stationary and functional aspects of the agonistic behavior in Tilapia macrochir (Boulanger 1912) (Piscer: Cichlidae)]. Acta Zool Pathol Antverp 58, 29-40.
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Banerjee, S. K., Dastidar, G., Mukhopadhyay, P. K., and Dehadrai, P. V. (1978). Toxicity of cadmium: a comparative study in the air-breathing fish, Clarias batrachus (Linn.) & in the non air-breathing one, Tilapia mossumbica (Peters). Indian J Exp Biol 16, 1274-7.
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Barash, D. P. (1975). Behavioral individuality in the cichlid fish, Tilapia mossambica. Behav Biol 13, 197-202.
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Barcellos, L. J. G., Nicolaiewsky, S., de Souza, S. M. G., and Lulhier, F. (1999). Plasmatic levels of cortisol in the response to acute stress in Nile tilapia, Oreochromis niloticus (L.), previously exposed to chronic stress. Aquaculture Research 30, 437-444.
Many studies have been made about the physiological effects of isolated chronic or acute stress. However, few studies have been made to assess the combination of both responses. The fish submitted to chronic stress may be subjected to an additional acute stressor. The aim of the present work was to evaluate the acute stress response in Nile tilapia Oreochromis niloticus (L.) previously subjected to chronic stress. For this, two experiments were performed. In the first experiment, the fish were subjected to chronic stress followed by an additional acute stress, In the second experiment, the fish were submitted only to an acute stress, The data showed that Nile tilapia fingerlings can adapt to chronic stress situations, and this decreases, but does not eliminate, their capacity to respond to an additional acute stressor, In both experiments, plasma cortisol levers reached a peak 1 h after administration of the acute stressor. In fish previously submitted to chronic stress, the highest concentration of plasma cortisol measured was 196 ng mL(-1). This value was significantly different from the cortisol concentration obtained in the second experiment (267 ng mL(-1)) with non-chronically stressed fish, The data also suggest that the chronic stress response can provoke a reduction in performance and growth rates compared with non- stressed fish.
Bardakci, F., and Skibinski, D. O. (1994). Application of the RAPD technique in tilapia fish: species and subspecies identification. Heredity 73, 117-23.
Random Amplified Polymorphic DNA (RAPD) analysis was applied to three species of the tilapia genus Oreochromis and four subspecies of O. niloticus. Thirteen random 10-mer primers were used to assay polymorphisms within and between populations. Different RAPD fragment patterns were observed for different species, although not always for different subspecies. Evidence is presented that RAPD markers might be useful for systemic investigation at the level of species and subspecies.
Bardakci, F., and Skibinski, D. O. (1999). A polymorphic SCAR-RAPD marker between species of tilapia (Pisces: Cichlidae). Anim Genet 30, 78-9.
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Basha, S. M., Prasada Rao, K. S., Sambasiva Rao, K. R., and Ramana Rao, K. V. (1983). Differential toxicity of malathion, BHC, and carbaryl to the freshwater fish, Tilapia mossambica (Peters). Bull Environ Contam Toxicol 31, 543-6.
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Basha, S. M., Rao, K. S., Rao, K. R., and Rao, K. V. (1984). Respiratory potentials of the fish (Tilapia mossambica) under malathion, carbaryl and lindane intoxication. Bull Environ Contam Toxicol 32, 570-4.
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Basiao, Z. U., and Doyle, R. W. (1999). Test of size-specific mass selection for Nile tilapia, Oreochromis niloticus L., cage farming in the Philippines. Aquaculture Research 30, 373-378.
One generation of mass selection based on the collimation procedure (early culling of large fry) was applied on Nile tilapia, Oreochromis niloticus L., in net cages set in Laguna de Bay, Philippines. The objective was to test the effectiveness of a low-cost, small-scale broodstock improvement procedure in this culture environment. Directional selection was performed in two steps after initial removal of large fry at 21 days. Selection of parents and testing of the offspring were also conducted in hapa net cages set up in Laguna de Bay. The selection resulted in a significant positive response of 3% relative to the control, which represents a projected 34% gain over 5 years in Laguna cage culture. The realized heritability is approximate to 16%.
Basu, J., Nandi, J., and Bern, H. A. (1965). The homolog of the pituitary-adrenocortical axis in the teleost fish Tilapia mossambica. J Exp Zool 159, 347-55.
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Belal, I. E. H., and Al-Dosari, M. (1999). Replacement of fish meal with Salicornia meal in feeds for Nile tilapia Oreochromis niloticus. Journal of the World Aquaculture Society 30, 285-289.
We investigated the use of the halophyte salicornia Salicornia bigelovii as a replacement for fish meal in feeds containing 35% crude protein for Nile tilapia Oreochromis niloticus. Five isocaloric, isonitrogenous diets were formulated with salicornia meal to replace 0%, 20%, 40%, 60%, and 80% of the fish meal in the feed. Another diet was formulated entirely from salicornia meal. Diets were fed to three replicate groups of tilapia fingerlings (mean initial weight = 0.5 g/fish) for 6 wk in 40-L aquaria supplied with 22 C well water. Tilapia growth did not differ (P < 0.05) for fish fed diets in which 0%, 20%, or 40% of the fish meal in the diet was replaced with salicornia meal. Weight gain was reduced when fish were fed diets with higher levels of salicornia meal, and growth was slowest for fish fed diets formulated entirely from salicornia meal. Body fat was reduced and body moisture content was increased (P < 0.05) for fish fed diets in which more than 80% of the fish meal was replaced with salicornia meal. We conclude that saIicornia meal can replace up to 40% of the fish meal in O. niloticus feeds without affecting growth or body composition.
Belal, I. E. H. (1999). Replacing dietary corn with barley seeds in Nile tilapia, Oreochromis niloticus (L.), feed. Aquaculture Research 30, 265-269.
Four isocaloric-isonitrogenous rations containing 0%, 15%, 30% and 51% of ground barley seeds as a replacement for dietary corn were fed to three replicate groups of Oreochromis niloticus (Linnaeus) fingerlings with a mean initial weight of 3.5 g. The randomly selected fish were tested for 9 weeks in 60 L circular tanks. Each tank was considered as an experimental unit. The tanks were put together in a water recirculating system using filtered and aerated ground well water (24 +/- 3 degrees C). Tilapia weight gain, feed conversion, specific growth rate and protein efficiency ratio were similar in fish fed diets containing 15% and 30% barley and were superior to those fed diets containing 0% control and 51% barley, There were no differences between tilapia fed diets containing 0% and 51% barley. Body moisture, crude fat, crude protein and total ash did not change as the level of barley in the feeds was increased.
Ber, R., and Daniel, V. (1992). Structure and sequence of the growth hormone-encoding gene from Tilapia nilotica. Gene 113, 245-50.
We report here the nucleotide (nt) sequence of the growth hormone (GH)- encoding gene (GH) of the tilapia fish (Tilapia nilotica). The T. nilotica GH gene, similar to that of the salmonidae fish, Atlantic salmon and rainbow trout, contains six exons and five introns. However, despite the presence of an additional intron (intron V), the size of the primary transcript of T. nilotica GH (1666 nt) is significantly shorter than that of all other currently characterized fish GH genes. Comparison of sequences upstream from the transcription start point of the tilapia, carp, rainbow trout and Atlantic salmon GH genes shows a region of high homology preceding the typical TATA box. This homology does not seem to extend to the regions further upstream of the compared fish GH genes and is not observed to be present in the corresponding region of the mammalian GH genes. A sequences search for putative DNA- binding domains for transcription factors shows the presence of short nt stretches similar to those considered to be involved in the tissue- specific expression of mammalian GH genes.
Ber, R., and Daniel, V. (1993). Sequence analysis suggests a recent duplication of the growth hormone- encoding gene in Tilapia nilotica. Gene 125, 143-50.
The sequence of two growth hormone(GH)-encoding genes from tilapia fish (Tilapia nilotica) is reported. Our data indicate that the presence of two GH in the tilapia genome is a consequence of a relatively recent duplication event. The two genes are highly homologous, having a similar intron (five)/exon (six) arrangement, and both encode an identical polypeptide. Sequence similarity extends up to bp -628 upstream to the transcription start point, after which the sequences of the two genes are not related to each other. The presence of two GH in the tilapia genome is supported both by the nucleotide sequence and by genomic DNA blot hybridization analysis. Tilapias, like salmonids, contain an extra intron compared with the mammalian GH structure. We suggest that within the superorder Teleostei, the insertion of intron 5 into GH took place after the evolutionary separation of Cyprinoidea, but before Isospondyli (salmonids) and Acanthopterygii (tilapias) were separated. Thus, the additional intron which is probably present in many teleost fish GH may provide an excellent natural marker for evolution and classification studies.
Bhaskar, M., and Govindappa, S. (1985). Tissue compensatory metabolic profiles in Tilapia mossambica (Peters) on acclimation to sublethal acidic and alkaline media. Gill glycogen metabolism. Arch Int Physiol Biochim 93, 59-63.
Freshwater Fish, Tilapia mossambica (Peters) was acclimated to sublethal acidic and alkaline media and branchial tissue glycogen metabolism was studied. In acidic media, the glycogenolysis is elevated in the tissues and glycolysis is suppressed. In contrast, in alkaline media, the tissue glycolytic pathway is accelerated with accumulation of organic acids. In both the cases tissue had elevated G-6-PDH activity indicating stress conditions on the tissue metabolism. The tissue compensatory changes provided survival value to the fish under altered pH media.
Bhaskar, M., and Govindappa, S. (1986). Acclimation to sublethal acidic and alkaline media of Tilapia mossambica (Peters): changes in glycogen metabolism of red muscle. Bull Environ Contam Toxicol 37, 113-9.
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Bhattacharyya, A., Sarkar, S. K., Basu, S. K., and Ganguly, S. (1989). Lactate dehydrogenase as genetic marker enzyme in fish Tilapia mossambica. Indian J Exp Biol 27, 913-4.
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Bhujel, R. C. (2000). A review of strategies for the management of Nile tilapia (Oreochromis niloticus) broodfish in seed production systems, especially hapa-based systems. Aquaculture 181, 37-59.
Low egg production per spawning and lack of spawning synchrony are the major problems of mass seed production in mouthbrooding tilapias. Collection of eggs or fry from the mouths of incubating females reared in large hapas suspended in fertilized ponds and incubating them artificially has been found to be commercially viable. However, fouling of the hapa is a major problem causing inconsistent performance of broodfish. In addition, other factors influencing with the tilapia seed output in hapa within pond systems are age and the size of the broodfish, feeding and feed management, environmental factors and management techniques. However, information on the factors affecting tilapia seed output is limited and scattered; therefore, this paper discusses the various aspects of management strategies based on the present state of knowledge and explores areas for the future research. (C) 2000 Elsevier Science B.V. All rights reserved.
Bijvelds, M., Kolar, Z., Bonga, S., and Flik, G. (1997). Mg2+ transport in plasma membrane vesicles of renal epithelium of the Mozambique tilapia (Oreochromis mossambicus). J Exp Biol 200, 1931-9.
To elucidate the mechanisms involved in Mg2+ transport at the apical and basolateral poles of the renal tubular epithelium, apical and basolateral plasma membrane vesicle preparations were derived from kidney tissue of freshwater- and seawater-adapted Mozambique tilapia Oreochromis mossambicus. Brush-border preparations were enriched 15.8- fold in alkaline phosphatase activity and consisted almost exclusively of right-side-out membrane vesicles. Basolateral membrane preparations were enriched 7.5-fold in Na+/K+-ATPase activity and contained resealed vesicles and leaky membrane fragments. Mg2+ association with brush- border and basolateral plasma membranes, traced using radioactive 27Mg, occurred in an osmotically active space. In all instances, Mg2+ binding to the vesicular membrane was low compared with the vesicular uptake. Mg2+ equilibration across the vesicular membrane of brush-border preparations was rapid and sensitive to the presence of extravesicular Ca2+, suggesting that the apical membrane of the renal epithelium contains a transport pathway for divalent cations. Application of various ionic gradients did not affect vesicular Mg2+ transport in apical and basolateral membrane preparations, suggesting the presence of an ion-coupled transport mechanism. ATP or ATP--S did not stimulate Mg2+ fluxes, indicating that Mg2+ transport does not proceed via an ATP- driven or activated transporter. In these aspects, vesicular Mg2+ transport was similar in seawater and freshwater preparations. These results suggest that the apical membrane of renal epithelial cells lacks an active secretory Mg2+ transport mechanism. We propose that the Mg2+ conductivity of the apical membrane reflects a route for downhill Mg2+ entry and is involved in renal Mg2+ reabsorption.
Bocci, M. (1999). Modelling the growth of Nile Tilapia (Oreochromis niloticus) feeding on natural resources in enclosures in Laguna de Bay (Philippines). Ecological Modelling 119, 135-148.
Laguna de Bay (Philippines), one of the largest freshwater bodies in the Southeast Asia, is located near Metro Manila. The lake is an important resource for the local population because of fish production: fishing and aquaculture are relevant activities for the economy of the area. Nile Tilapia (Oreochromis niloticus) is one of the cultured species and it is grown within net cages in the lake. In this paper, a model is proposed to describe the growth of Nile Tilapia under natural conditions; food sources have been considered to be phytoplankton, zooplankton and suspended organic matter (detritus), without additional feed supply. The metabolic approach has been adopted to describe fish growth. The parameters characterising fish metabolism have been estimated for O. niloticus or similar species, according to literature information. The model has been applied to twelve growing conditions representative of increasing stocking densities and of different growing periods. Model results have been successfully compared with the experimental data reported in literature. This model has been used to estimate the amount of natural food (phytoplankton) exploited by the culture of O. niloticus with the final aim to quantitatively relate lake's water quality with fish growth and production. (C) 1999 Elsevier Science B.V. All rights reserved.
Bonga, S. E., and van der Meij, J. C. (1980). The effect of ambient calcium on prolactin cell activity and plasma electrolytes in Sarotherodon mossambicus (Tilapia mossambica). Gen Comp Endocrinol 40, 391-401.
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Borski, R. J., Yoshikawa, J. S., Madsen, S. S., Nishioka, R. S., Zabetian, C., Bern, H. A., and Grau, E. G. (1994). Effects of environmental salinity on pituitary growth hormone content and cell activity in the euryhaline tilapia, Oreochromis mossambicus. Gen Comp Endocrinol 95, 483-94.
Studies were undertaken to determine whether several indicators of growth hormone (GH) cell activity, namely GH content, fine structure, and volume of the GH region, differ in the pituitaries of freshwater (FW) and seawater (SW) tilapia, Oreochromis mossambicus. Tilapia raised from the stage of yolk-sac absorption for 7 months in SW contain significantly more GH in their pituitaries than in those of fish reared in FW. Pituitary growth hormone content in tilapia raised in FW for 7 months and transferred to SW for 49 days is greater than that in sibling tilapia retained in FW. Conversely, GH content is significantly lower in the pituitaries of SW-reared tilapia transferred to FW for 49 days than that in the pituitaries from fish retained in SW. Likewise, the volume of the GH region and activity of the GH cells are enhanced in pituitaries from SW-reared tilapia over that seen in pituitaries from FW fish. Taken together, all data indicate heightened GH cell activity in SW-raised tilapia and suggest that GH may play a causal role in the greater growth rates observed in SW tilapia compared to FW fish and/or that GH may be involved in SW osmoregulation. The latter suggestion is supported, in part, by our observation that in vivo oGH treatment (2 micrograms/g body wt) stimulated gill Na+,K(+)-ATPase activity.
Bury, N., Flik, G., Eddy, F., and Codd, G. (1996). The effects of cyanobacteria and the cyanobacterial toxin microcystin- LR on Ca2+ transport and Na+/K+-ATPase in tilapia gills. J Exp Biol 199, 1319-26.
The effects of cytotoxic substances from cyanobacteria on ionic transport processes in tilapia (Oreochromis mossambicus) were examined. Inhibitory effects on ionic transport including whole-body Ca2+ fluxes and P-type ATPases of the gill were found. The compounds tested were (1) purified microcystin-LR (MC-LR), a heptapeptide hepatotoxin produced by the cyanobacterium Microcystis aeruginosa, (2) extracts from M. aeruginosa strain PCC 7820, a strain producing MC-LR and other microcystin variants, and (3) extracts of M. aeruginosa CYA 43, a strain producing toxins including small quantities of MC-LR. Whole-body Ca2+ influx was inhibited by a 24 h exposure to extracts of M. aeruginosa CYA 43 and 7820, but not by exposure to an equivalent amount (90 mg l-1) of purified MC-LR. Shorter exposure times (4 h) were ineffective. Fish exposed to extracts from M. aeruginosa CYA 43 showed significant plasma hypocalcaemia. Both strains of M. aeruginosa inhibited Ca2+ uptake by basolateral plasma membrane vesicles (BLMVs), endoplasmic reticulum (ER) and mitochondria, as well as BLMV K+- dependent p-nitrophenol phosphatase (pNPPase) activity. The hydrophobic fractions of the cyanobacterial extracts were the most potent, inhibiting BLMV, ER and mitochondrial Ca2+ uptake by up to 99 %, but they were less inhibitory of BLMV K+-dependent pNPPase activity. Purified MC-LR was without effect on these preparations. In conclusion, cytotoxic substances from cyanobacteria have the potential to disrupt normal physiological processes dependent upon Ca2+ transport processes in tilapia gills.
Byamungu, N., Corneillie, S., Mol, K., Darras, V., and Kuhn, E. R. (1990). Stimulation of thyroid function by several pituitary hormones results in an increase in plasma thyroxine and reverse triiodothyronine in tilapia (Tilapia nilotica). Gen Comp Endocrinol 80, 33-40.
In this study, intravenous injection of several doses of porcine follicle stimulating hormone (pFSH: 0.002, 0.01, 0.05, and 0.5 micrograms/g body wt), bovine TSH (bTSH: 0.5 micrograms/g body wt), and ovine growth hormone (oGH: 0.04, 0.02, and 0.4 microgram/g body wt) stimulated an increase in plasma thyroxine (T4) and reverse triiodothyronine (rT3) in tilapia. This effect occurred in a dose- dependent manner. pFSH was the most potent in stimulating thyroid function. The dose of 0.002 microgram pFSH/g body wt increased plasma levels of T4 over control levels (2.59 +/- 0.16 ng/ml) about 2.5-fold within 4 hr, whereas a concentration of 0.5 micrograms/g body wt caused a great and prolonged increase of T4 and rT3 levels. Control levels (2.59 +/- 0.16 ng/ml for T4 and 40.37 +/- 8.60 pg/ml for rT3) were increased 19- and 22-fold respectively, over 24 hr. An increase of T4 and rT3 levels occurred also after injection of total hypophyseal extract and Con A II glycoprotein fraction of a tilapia pituitary homogenate, whereas the protein fraction failed to alter plasma concentrations of T4 and rT3. rT3 levels were also significantly increased at 2 hr, but not at 1 hr, after injection of T4. Basal T3 levels (1.90 +/- 0.22 ng/ml) were reduced by half over 24 hr in all experiments. These results suggest the existence, in tilapia, of a 5-D pathway deiodination of T4 which is pituitary independent. Stimulation of T4 release is always followed by an increase in plasma rT3 levels.
Byamungu, N., Darras, V. M., and Kuhn, E. R. (1991). Purification of tilapia thyrotropin from a crude pituitary homogenate by immunoaffinity chromatography using a matrix of antibodies against porcine follicle-stimulating hormone. Gen Comp Endocrinol 84, 183-91.
An immunoadsorbent matrix using antibodies against porcine follicle- stimulating hormone (pFSH), a high heterothyrotropic stimulant in tilapia, was used to purify tilapia thyrotropic hormone (t-TSH) from crude pituitary extracts. A homologous bioassay monitored TSH bioactivity during the purification. Thyroid hormones (thyroxine, T4; triiodothyronine, T3; and reverse triiodothyronine, rT3) and testosterone were measured in vivo in Tilapia nilotica. TSH activity eluted as one major peak at pH 2.8 using a PBS-glycine buffer. The TSH fraction increased plasma T4 and plasma rT3. The potency of tTSH was comparable to that of pituitary extract or its Con A II fraction; however, pFSH was a stronger thyroid stimulant. tTSH had no effect on plasma T3 levels and was free of gonadotropic activity, as indicated by its failure to alter plasma testosterone concentrations. Chromatographic and electrophoretic analyses demonstrated a high degree of purity. Like other vertebrate TSHs, the tTSH appeared to have a subunit structure with a possible microgeneity in one subunit.
Byamungu, N., Mol, K., and Kuhn, E. R. (1991). Somatostatin increases plasma T3 concentrations in Tilapia nilotica in the presence of increased plasma T4 levels. Gen Comp Endocrinol 82, 401-6.
An injection of ovine growth hormone, porcine follicle stimulating hormone, and bovine thyrotropin stimulating hormone increased in Tilapia nilotica plasma concentrations of thyroxine (T4) and reverse triiodothyronine (rT3) after 4 and 8 hr, whereas plasma concentrations of T3 were unaffected. An injection of somatostatin (SRIF) alone did not influence thyroid hormone levels. If, however, SRIF was injected together with these hormones, which raised plasma T4, or together with T4 itself, an increase in plasma concentrations of T3 could be observed, whereas the increase in rT3 was less pronounced. It is concluded that SRIF may change the normal 5-deiodinase (5-D) activity and increased rT3 during hyperthyroxinemia into a 5'-D activity and a rise in T3, respectively, in T. nilotica.
Callard, G. V., Specker, J. L., Knapp, J., Nishioka, R. S., and Bern, H. A. (1988). Aromatase is concentrated in the proximal pars distalis of tilapia pituitary. Gen Comp Endocrinol 71, 70-9.
Aromatase has been identified in the telostean, avian, and mammalian pituitaries, although its cellular location(s) is not yet certain. To address this question, experiments were performed in tilapia (Oreochromis mossambicus), a species which has been well characterized with respect to the intraglandular distribution of the different pituitary cell types. To estimate aromatase, glands were microdissected into rostral pars distalis (RPD), proximal pars distalis (PPD), and neurointermediate lobe (NIL) and organs were cultured in the presence of [3H]androstenedione for 16-24 hr. [3H]Estrogen products were isolated and quantified after ether extraction, hydrolysis with glucuronidase-sulfatase, thin-layer chromatography, and phenolic partition. Authentic estrone or estradiol-17 beta were produced by all pituitary regions and also by the urophyseal region of the spinal cord. Aromatase was two to five times higher in PPD than in RPD or NIL and similar to activity in adjacent hypothalamus-preoptic area (HPOA). Much lower estrogen yields were obtained in cultures of cerebellum, urophysis, and other cord regions. Since the PPD contains most of the somatotropes, these data are consistent with earlier studies implicating GH3/GH4 cell strains as an enriched enzyme source, although its presence in other cell types cannot be ruled out. The unusually high and localized aromatase in tilapia pituitary renders this species a useful model for studying the targets and functional importance of estrogen as a parahormone in the pituitary.
Camargo, L. d. A., and Belda Neto, F. M. (1969). [Chemical and nutritional aspects of "Tilapia Melanopleura, Dumeril, 1859"]. Rev Fac Farm Odontol Araraquara 3, 259-65.
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Carrasco, L. A. P., Penman, D. J., and Bromage, N. (1999). Evidence for the presence of sex chromosomes in the Nile tilapia (Oreochromis niloticus) from synaptonemal complex analysis of XX, XY and YY genotypes. Aquaculture 173, 207-218.
A cytogenetic analysis of chromosome synapsis was carried out during the first meiotic prophase of the Nile tilapia, Oreochromis niloticus. Three different genotypes were studied: XX sex-reversed males, 'wild-type' (XY) males and YY 'supermales'. TEM analysis of synaptonemal complex (SC) spreads revealed the presence of 22 fully paired bivalents during pachytene in both homogametic genotypes. In the heterogametic genotype, an incompletely paired segment was frequently observed during the process of meiotic synapsis in the terminal region of the longest bivalent. The presence of this unpaired segment, together with several features characteristic of sex- chromosome behaviour during meiosis, suggests the existence of a non-homologous region in this chromosomal pair in the heterogametic genotype, and provides cytological evidence for the chromosomal basis of sex determination in O. niloticus. The usefulness of SC analysis for the understanding of sex determination and its relevance in the management of species of aquacultural importance are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.
Carrieri, M. P., and Volpato, G. L. (1991). Does snatching frequency really indicate food ingestion in the Nile tilapia? Physiol Behav 50, 489-92.
The fitness of the snatching frequency as an indicator of food intake in Nile tilapia fingerlings, Oreochromis niloticus (L), was studied. Five groups of four individuals each were used after a two-day starvation period. The hierarchical rank among individuals in the same group was registered. Food in the form of tiny pellets (ranging from 1.30 to 1.95 mm in diameter) was offered, and the individual snatching frequency was observed during a 20-min period. The animals were then sacrificed for evaluation of stomach contents. It was concluded that snatching frequency is not a good parameter to indicate individual food intake in this species when fed as a group with pellets crushed into tiny particles. This raises a problem for investigations that require evaluation of the cumulative effect of competition on food intake, such as growth or conversion efficiency studies. Furthermore, a very low correlation between snatching frequency and food intake was shown in the third hierarchical rank. It is suggested that the linearity assumed in such hierarchies should be reconsidered.
Caruso, D., and Lazard, J. (1999). Subordination stress in Nile tilapia and its effect on plasma lysozyme activity. Journal of Fish Biology 55, 451-454.
Dominant Nile tilapia had significantly higher lysozyme activity than did subordinate fishes (alpha = 0.05). Plasma lysozyme level was not correlated with sex, parental origin, rearing length, weight, condition factor or rearing density. (C) 1999 The Fisheries Society of the British Isles.
Chan, K. M. (1994). PCR-cloning of goldfish and tilapia metallothionein complementary DNAs. Biochem Biophys Res Commun 205, 368-74.
Metallothionein (MT) is believed to be a sensitive and effective "biomarker" for monitoring metal contamination in fish. Comparison of amino acid sequences between flounder MT and trout MT revealed that there is a conserved region at their N-terminals. Using oligonucleotides derived from this conserved region, reverse transcription- polymerase chain reaction (RT-PCR) was performed to obtain MT complementary DNAs (cDNAs) from goldfish, Carassius auratus, and tilapia, Tilapia mossambica. These cDNA probes would be useful in developing sensitive PCR-based methods to detect MT gene expression for monitoring metal pollution in local waters.
Chan, W. L., Chan, C. H., and Chan, T. Y. (1999). Vibrio vulnificus septicaemia and necrotizing fasciitis after a prick from the dorsal fin of a tilapia. Trans R Soc Trop Med Hyg 93, 174.
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Chan, W. L., Chan, C. H. S., and Chan, T. Y. K. (1999). Vibrio vulnificus septicaemia and necrotizing fasciitis after a prick from the dorsal fin of a tilapia. Transactions of the Royal Society of Tropical Medicine and Hygiene 93, 174-174.
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Chang, C. U., and Liao, C. F. (1994). Characterization of beta-adrenoceptors of tilapia erythrocytes with hydrophobic and hydrophilic radioligands. Chin J Physiol 37, 153-9.
Tilapia are widely used for to investigate stress physiology, and beta- adrenoceptors in fish erythrocytes play important roles in response to hypoxia and other environmental stresses. As the beta-adrenoceptor in tilapia erythrocytes has never been investigated, we characterized beta- adrenoceptors in intact red blood cells of a tilapia (Oreochromis mossambicus) in this study by radioligand binding assay with a hydrophobic beta-adrenoceptor antagonist, 1-[4,6-propyl- 3H]dihydroalprenolol ([3H]DHA), and a hydrophilic ligand (-)-4-(3-t- butylamino-2-hydroxypropoxy)-[5,7-3H] benzimidazol-2-one ([3H]CGP- 12177). The equilibrium dissociation constant (KD) for [3H]CGP-12177 calculated from kinetic experiments (KD = 5.8 +/- 4.8 nM) was comparable to that obtained from Scatchard analysis (KD = 1.22 +/- 0.18 nM). However, the KD for [3H]DHA obtained from kinetic studies (KD = 0.41 +/- 0.12 nM) was much smaller than that from a Scatchard plot (KD = 7.8 +/- 1.6 nM). The hydrophobic [3H]DHA bound to two sites (KD = 7.8 nM, Bmax = 12,500 sites/cell and KD = 77.4 nM, Bmax = 70,550 sites/cell), whereas the hydrophilic [3H]CGP-12177 bound to one site (KD = 1.2 nM, Bmax = 1,900 sites/cell). The results indicate that high- affinity beta-adrenoceptors are located both on the surface of and inside tilapia erythrocytes, and low-affinity receptors exist only inside erythrocytes.
Chang, C. F., and Lin, S. J. (1995). Immersion in bovine insulin stimulates growth of tilapia. Reprod Nutr Dev 35, 95-103.
The objective of this study was to investigate the effects of bovine insulin on growth responses in tilapia. Juvenile hybrid male tilapia (Oreochromis niloticus x O aurea; n = 135) were subjected to 1 of 3 treatments. Each treatment was subdivided into 3 replicates of 15 fish each. The fish were immersed into 1 of 2 doses (10 and 100 micrograms/100 ml water) of insulin or no hormone for 15 min per week for 8 weeks. Body weight, growth and feed conversion efficiency were significantly higher as a result of the first 4 weeks of insulin treatment as compared to control fish. The lower dose of insulin had a better stimulation effect than that of the higher doses. Insulin also stimulated feed consumption. Liver protein and protein/DNA ratio were higher in both insulin-treated groups than in the control group. Muscle proximate composition and hepatosomatic index were similar in the insulin-treated and control groups. The experimental findings suggest that insulin administered by immersion can enhance growth, feed consumption, food utilization and liver cell size in tilapia.
Chang, X. T., Kobayashi, T., Kajiura, H., Nakamura, M., and Nagahama, Y. (1997). Isolation and characterization of the cDNA encoding the tilapia (Oreochromis niloticus) cytochrome P450 aromatase (P450arom): changes in P450arom mRNA, protein and enzyme activity in ovarian follicles during oogenesis. J Mol Endocrinol 18, 57-66.
A cDNA clone encoding the complete tilapia (a teleost fish, Oreochromis niloticus) cytochrome P450 aromatase (P450arom) was isolated from an ovarian follicle cDNA library. The deduced amino acid sequence (522 amino acid residues) had 72.2% and 59.5% homology with rainbow trout and catfish P450arom respectively, and about 50% homology with mammalian and avian P450arom. Expression of this cDNA in COS-7 cells produced a protein that converted exogenous testosterone to estrogens. Northern blots using a tilapia P450arom cDNA fragment and Western blots using an antiserum against a tilapia P450arom polypeptide fragment revealed a single P450arom mRNA (2.6 kb) and a single protein (59 kDa) in tilapia ovarian tissue respectively. These analyses also revealed that the levels of both P450arom mRNA and protein were low in early vitellogenic follicles, increased in midvitellogenic follicles, and declined to non-detectable levels in post-vitellogenic follicles. Changes in the ability of follicles to convert exogenous testosterone to estrogens (aromatase activity) were similar to those of P450arom mRNA and protein. These observations indicated that the capacity of tilapia ovarian follicles to synthesize estradiol-17 beta is closely related to the contents of P450arom mRNA and protein within them.
Chang, M. H., Lin, H. C., and Hwang, P. P. (1998). Ca2+ uptake and Cd2+ accumulation in larval tilapia (Oreochromis mossambicus) acclimated to waterborne Cd2+. Am J Physiol 274, R1570-7.
The present study compares the rates of Ca2+ uptake and Cd2+ accumulation in tilapia (Oreochromis mossambicus) between larvae preexposed to Cd2+ and naive larvae. Preexposure to Cd2+ induces some form of adaptation that attenuates the effects of Cd2+ later on. Exposure to Cd2+ decreased the uptake of Ca2+ but did not suppress the accumulation rate of Cd2+. A 12-fold increase in 96-h half-maximal lethal concentration was found in tilapia larvae preexposed to 0.45 microM Cd2+ from hatching for 3 days in comparison with naive 3-day-old larvae. The effects of Cd2+ on Ca2+ influx kinetics in larvae preexposed to 0.18 microM Cd2+ for 3 days were examined. The Michaelis constant for Ca2+ in the 0.18 microM Cd2+ preexposed larvae did not change significantly in the presence of Cd2+, whereas maximal velocity increased by approximately 23%. An enhanced Ca2+ uptake efficiency ( approximately 18%) was found in these Cd2+-acclimated larvae. The criterion that determines the survival of tilapia larvae encountering Cd2+ challenge is the degree of interference with Ca2+ homeostasis instead of the absolute amount of Cd2+ accumulated.
Chang, X. T., Kobayashi, T., Todo, T., Ikeuchi, T., Yoshiura, M., Kajiura-Kobayashi, H., Morrey, C., and Nagahama, Y. (1999). Molecular cloning of estrogen receptors alpha and beta in the ovary of a teleost fish, the Tilapia (Oreochromis niloticus). Zoological Science 16, 653-658.
Estrogen receptors (ER) in mammals have recently been shown to be encoded by two distinct genes, ER alpha and ER beta. In this study, cDNAs encoding two tilapia ER subtypes, tER5.1 and tER4.3, were cloned from an ovarian cDNA library of a teleost fish, the tilapia Oreochromis niloticus. The tER5.1 and tER4.3 contain complete open reading frames encoding 585 and 557 amino acid residues, respectively. The two receptors share about 12% homology in the A/B domain, 96% in the DNA binding domain (C domain), 12% in the D domain, 57% in the ligand binding domain (E damain), and 20% in the F domain. Phylogenetic analysis of ER proteins from various vertebrate species indicated that vertebrate ERs consist of two major groups (ER alpha and ER beta); tER5.1 and tER4.3 belong to ER alpha and ER beta subtypes, respectively. Thus, we consider tER5.1 and tER4.3 to be the tilapia homologs of ER alpha (tER alpha) and ER beta (tER beta), respectively. In transient transfection assays using mammalian COS-7 cells, both tER alpha and tER beta showed estradiol-17 beta dependent activation of transcription from the estrogen-responsive ERE-Luc promoter. This is the first report of the presence of ER alpha and ER beta within a single non-mammalian vertebrate species.
Change, X. T. (1999). Molecular cloning of estrogen receptors alpha and beta in the ovary of a teleost fish, the Tilapia (Oreochromis niloticus) (vol 16, pg 653, 1999). Zoological Science 16, 853-853.
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Chen, J. D., Yew, F. H., and Li, G. C. (1988). Thermal adaptation and heat shock response of Tilapia ovary cells. J Cell Physiol 134, 189-99.
The growth of tissue culture TO-2 cells derived from the warm water fish Tilapia, the induction of thermotolerance, and protein synthesis profiles of these cells in response to temperature changes were examined. TO-2 cells can grow between 15 to 34 degrees, with an optimal growth temperature of 31 degrees. There is no apparent killing of the cells when the temperature is lowered to 4 degrees for up to 3 days. Survival of TO-2 cells at 43 degrees was studied after various preheat treatments: 1) acute heating at 40 degrees for 15 min followed by 31 degrees incubation, 2) chronic exposure at 37 degrees for several hr, or 3) long-term thermal adaptation at 34 degrees. The cells acquire thermotolerance from pre-exposure to 37 degrees for as short as 6 hr. Preheating at 40 degrees followed by incubation at 31 degrees also induces thermotolerance against a subsequent 43 degrees heat challenge. In addition, 34 degrees thermal adapted cells are resistant to 43 degrees heating. One- and two-dimensional gel electrophoresis of proteins after heat treatments show that three major heat shock proteins with molecular weights around 87, 70, and 27 kD are preferentially synthesized. The synthesis of two additional proteins with an isoelectric point of 6.9 and molecular weights of 60 and 44 kD are significantly enhanced in 34 degrees thermal-adapted and 37 degrees chronic heated cells, but not in cells subjected to an acute heat shock at either 40 degrees or 43 degrees. On the other hand, the 27 kD heat shock proteins are mainly present in the 43 degrees, 40 degrees, and 37 degrees heat-shocked cells, but not in the 34 degrees thermal-adapted cells.
Chen, J. D., and Yew, F. H. (1988). DNA replication and repair of Tilapia cells. II. Effects of temperature on DNA replication and ultraviolet repair in Tilapia ovary cells. J Cell Sci 89, 263-72.
TO-2 is a fish cell line derived from the Tilapia ovary. It grows over a wide range of temperature (15-34 degrees C). While most fish cells lack DNA excision repair and are hypersensitive to ultraviolet light (u.v.), Tilapia cells are more u.v.-resistant than mammalian cells. In this paper we report the effects of temperature on DNA replication and u.v. repair in TO-2 cells. When the cells were moved from 31 degrees C to the sublethal high temperature of 37 degrees C, the rate of DNA synthesis first decreased to 60%, then speedy recovery soon set in, and after 8 h at 37 degrees C the rate of DNA synthesis overshot the 31 degrees C control level by 180%. When moved to low temperature (18 degrees C) Tilapia cells also showed an initial suppression of DNA synthesis before settling at 30% of the control level. u.v. reduced but could not block DNA synthesis completely. The inhibition was overcome in 3 h at 37, 31 and 25 degrees C, but not at 18 degrees C. Initiation of nascent DNA synthesis was blocked at 4 J m-2 in TO-2 cells compared with less than or equal to 1 J m-2 in mammalian cells. After 9 J m-2 u.v. irradiation, low molecular weight DNA replication intermediates started to accumulate, and they could be chased into high molecular weight DNA with little delay. TO-2 cells showed low levels of u.v.- induced excision repair; but this was prominent compared with other fish cells. The u.v.-induced incision rate has been measured at various temperatures, and the activation energy of incision estimated to be 13 kcal mol-1 (1 cal approximately equal to 4.184 J).
Chen, J. Y., Chang, C. Y., Chen, J. C., Shen, S. C., and Wu, J. L. (1997). Production of biologically active recombinant tilapia insulin-like growth factor-II polypeptides in Escherichia coli cells and characterization of the genomic structure of the coding region. DNA Cell Biol 16, 883-92.
Insulin-like growth factor-II (IGF-II) is a fetal growth factor in humans, but has not been clearly identified in fish up to now. For a detailed understanding of the physiological response of fish IGF-II, the first step was to clone tilapia IGF-II cDNA from the brain cDNA library, coding the region of genomic DNA, and also expressing tilapia IGF-II polypeptides from Escherichia coli. Tilapia cDNA sequences total 1,977 bp, and predicted nucleotide sequences and amino acid sequences of tilapia share 77.9% and 90.7% homology identity with rainbow trout IGF-II, respectively. The genomic structure of the tilapia prepro-IGF- II coding region is very difficult to sequence in mammals and birds. The cloned tilapia IGF-II gene coding region appears much more complex than in other vertebrates. In tilapia IGF-II, the first coding exon I encoding part of the signal peptide sequence is 25 amino acids shorter than the first coding exon of mammals and birds. The other 23 amino acids of the signal peptide, and the first amino acids of the B domain and C domain are encoded by tilapia coding exon 2. The C, A, and D domains, and the first 20 amino acids of the E peptide are encoded by tilapia coding exon 3. The other E peptides and the 3' untranslated region (UTR) region are encoded by tilapia coding exon 4. These data show that the IGF-II genes have significantly differing structures in vertebrate evolution, and there are differences of interrupting introns in the IGF-I genomic structure compared with mammals. To obtain recombinant biologically active polypeptides, tilapia IGF-II B-C-A-D domains were amplified using the polymerase chain reaction (PCR), then ligated with glutathione S-transferase (GST, pGEX-2T vector). Tilapia recombinant IGF-II protein was purified and characterized in E. coli. The fusion protein was also digested with thrombin and appeared as a recombinant IGF-II polypeptide single band with a molecular mass of 7 kD. The recombinant tilapia IGF-II protein biological function was measured by stimulation of [3H]thymidine incorporation. The assay concentration was set up from 0 to 120 nM to stimulate tilapia ovary cell line (TO-2) significantly to uptake thymidine. The results suggest that the recombinant IGF-II protein was dose dependent.
Chen, J. Y., Tsai, H. L., Chang, C. Y., Wang, J. I., Shen, S. C., and Wu, J. L. (1998). Isolation and characterization of tilapia (Oreochromis mossambicus) insulin-like growth factors gene and proximal promoter region. DNA Cell Biol 17, 359-76.
To understand the molecular mechanism which controls the transcription of the insulin-like growth factors (IGFs) gene, we have cloned and sequenced the cDNA for the proximal promoter region of the tilapia IGFs gene and have characterized its activity by chloramphenicol acetyltransferase (CAT) transient transfected expression assays. Tilapia (Oreochromis mossambicus) IGF-I cDNA (549 bp) was amplified by PCR from single-stranded cDNA of growth hormone (GH)-induced liver RNA using a pair of oligonucleotides specific for fish IGF-I as amplification primers. Tilapia IGF-I and IGF-II 5' termini were analyzed by rapid amplification of cDNA 5' ends (5'RACE). Analysis of the 5'RACE results revealed two transcription start sites in IGF-I and one transcription start site in IGF-II. Different fragments of the 5' flanking region were transfected into human lung adenocarcinoma cells. In the cell line, maximum promoter activity was located in the distal 657 basepairs of the IGF-I 5' flanking region and in the distal 450 basepairs of the IGF-II 5' flanking region. The in vivo actions of the IGFs promoter on developmental stage expression were investigated further in transgenic zebrafish in which an IGFs promoter-driven green fluorescent protein (GFP) encoding the cDNA transgene was microinjected into embryos. Morphologic and RT-PCR studies of the transgenic zebrafish indicated that IGF-I promoter-driven GFP transcripts appeared for the first time in the 1-K-cell stage and the IGF-II promoter-driven GFP transcripts appeared for the first time in the 32-cell stage. Fluorescent (GFP) distribution was apparent within 48 h in IGF-II- transgenic zebrafish embryos, especially in eye, muscle, corpuscle, floor plate, horizontal myoseptum, yolk sac extension, and yolk sac. These results indicate that the IGF-I and IGF-II promoters are active in tissue and in a development-specific manner. Our findings also indicate that the IGF-II promoter influences the growth of fish embryos earlier than does IGF-I, and IGF-II has higher levels of expression than does IGF-I. These results suggest that the IGF-II promoter plays a growth factor role in teleost embryo development.
Chiayvareesajja, J., Roed, K. H., Eknath, A. E., Danting, J. C., De Vera, M. P., and Bentsen, H. B. (1999). Genetic variation in lytic activities of blood serum from Nile tilapia and genetic associations with survival and body weight. Aquaculture 175, 49-62.
A study was carried out on lysozyme activity and spontaneous haemolytic (SH) activity of blood serum from 388 individuals of Nile tilapia (Oreochromis niloticus) coming from 42 full-sib groups within 21 paternal half-sib groups. The lysozyme activity was measured at both 15 degrees C and 30 degrees C incubation temperatures, whereas SH activity was measured at 30 degrees C incubation temperature, Significant variation in lysozyme activity was detected between half-sib groups at 30 degrees C incubation temperature, but not at 15 degrees C incubation temperature and not for SH activity. Significant variation was found between full-sib groups for all parameters. The estimated heritabilities of lysozyme activity were relatively high (0.6-0.7) at 30 degrees C incubation temperature and intermediate (about 0.3) at 15 degrees C incubation temperature. The heritability estimate of SH activity was zero according to estimates based both on the sire component of variance and on variance components from an individual animal model, whereas the estimate based on the dam component of variance was about 0.7 and highly significant, Survival and growth were recorded after a grow-out period of 120 days in individuals from a parallel set of samples from the same sib families. Significant negative correlations were found between least-squares means in the parallel sib groups for lysozyme activity and survival rates for both half-sib groups (r = -0.53; P = 0.01) and full-sib groups (r = -0.32; P = 0.04). No significant correlations were found between SH activity and survival rate nor between lytic activities and body weight at harvest. (C) 1999 Elsevier Science B.V. All rights reserved.
Chimbari, M. J., Ndamba, J., and Madsen, H. (1996). Food selection behaviour of potential biological agents to control intermediate host snails of schistosomiasis: Sargochromis codringtoni and Tilapia rendalli. Acta Trop 61, 191-9.
The food selection behaviour of two fish species indigenous to Zimbabwe (Tilapia rendalli and Sargochromis codringtoni) was studied under laboratory conditions with a view to considering them as biological agents for snail control. Six glass aquaria were set up and divided into two sets each with two aquaria. One S. codringtoni was introduced into each aquarium of the first set while one T. rendalli was introduced into each aquarium of the other set. In one of the aquaria of each set the fish were supplied with snails and trout food. Snails and weeds were provided, but trout food was excluded in the second aquarium of each set while the third aquarium for each set was provided with trout food, snails and weeds. A fourth aquarium with weeds and snails but no fish was set up as a control. Data collected over 9 weeks showed that T. rendalli was primarily herbivorous while S. codringtoni was shown to be malacophagous. Presence of trout food made no difference in the snail-eating habit of S. codringtoni or the weed- eating behaviour of T. rendalli. However, trout food seemed to be a good protein supplement to T. rendalli as the fish with access to trout food gained more weight and length.
Chistova, M. N. (1971). [Hormonal effects on vitellogenesis and fertility rates in tilapian fish, Tilapia mossambica Peters]. Dokl Akad Nauk SSSR 200, 1479-82.
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Chmilevskii, D. A., and Ivoilov, A. A. (1978). [Effect of irradiation on early gametogenesis in Tilapia]. Tsitologiia 20, 1264-8.
The 10 day old fries of Tilapia mossambica Peters were irradiated with 350 R dose. Dynamics of germ cells in control and after irradiation was studied. In 10 day old fry primordial germ cells and gonial cells were observed; in 15 days--mainly gonial cells were seen; in 20 days part of gonial cells move in the early prophase of meiosis; in 25 days gonial cells and oocytes of early prophase of meiosis are seen; in 30 days oogonial cells, oocytes of early prophase of meiosis and of previtellogenesis are observed. After irradiation of 13--14 day old fries some anomalies of mitosis were observed. But mass destruction of germ cells took place during the pachytene stage in 25 day old fries. The causes of the destruction of germ cells are discussed.
Chmilevskii, D. A., and Mel'nikova, I. V. (1988). [Effect of X-rays on the oogenesis of tilapia (Oreochromis mossambicus Peters.). IV. Irradiation of fish at the age of 30 and 60 days]. Ontogenez 19, l56-64.
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Chou, B. S., and Shiau, S. Y. (1999). Both n-6 and n-3 fatty acids are required for maximal growth of juvenile hybrid tilapia. North American Journal of Aquaculture 61, 13-20.
An 8-week feeding experiment was conducted to provide preliminary information on essential fatty acid requirements of hybrid tilapia (female Nile tilapia Oreochromis niloticus x male blue tilapia O. aureus). Seven semipurified diets containing 30% crude protein from casein with 3.2 kcal available energy/g were supplemented with 5% of either lard (L), corn oil (C), cod liver oil (F), lard and corn oil (1:1, L-C), lard and cod liver oil (1:1, L-F), corn oil and cod liver oil (1:1, C-F), or lard, corn oil, and cod liver oil(1:1:1, L- C-F). Each diet was fed to three replicate groups of fish initially weighing 0.84 +/- 0.02 g (mean +/- SD) in 60-L aquaria connected as a closed recirculating-water system containing freshwater at 25 +/- 1 degrees C. Results indicate that significantly (P < 0.05) higher weight gain, feed efficiency (FE), protein efficiency ratio (PER), and protein deposition (PD) were associated with fish fed the diet supplemented with F. Among groups fed diets containing F, weight gain was significantly higher in fish fed L-C-F than in fish fed L-F and F. Fish fed L-C-F had significantly higher FE and PER values than those fed F, LF or C-E Protein deposition was significantly better in fish fed GC-F than in fish fed L-E Fatty acid compositions of liver and muscle in fish generally reflected the composition of the diet. These data suggest that n-3 highly unsaturated fatty acid as well as n-6 fatty acid are essential for maximum growth of juvenile hybrid tilapia.
Chrappa, V., and Sabo, V. (1999). Feeding meals of housefly larvae and pupae to the Nile tilapia (Oreochromis niloticus). Czech Journal of Animal Science 44, 81-85.
Two trials were conducted to study the feeding of meals made of housefly larvae and pul,ne to the Nile tilapia (Oreochromis niloticus) as a fifty-percent and full replacement of fish meal in granular isoprotein feed mixtures. Formulations of these feeds ate shown in Tabs. I and II. Trial No. I (started on 28th May 1996) involved 25 tilapias in a group of average live weight of 46.7 g and body length 105 nm. The trial lasted 28 weeks. Trial No. ? (started on 18th July 1996), lasting 46 weeks. involved fish with initial live weight of 16.6 g and body length 60 mm. The group comprised 30 individuals. Each group was kept in a 200-liter aquarium. Water temperature ranged from 23 to 25 degrees C. The aquaria were filled with new water. in about 10-day intervals. The feeding of both types of meals at both replacements did not significantly influence the live weight and body length of Fish (P > 0.05); a trend of higher live weight was observed in experimental groups (Figs. 1 and 7). Feed conversion was lower in the meal of housefly larvae (by 12.0 and 4.7%) and higher iii that of housefly pupae (by 28.6 and 21.1%). Fish mortality was not influenced by feeding these meals. Caress analyses showed that gill weight significantly (P < 0.05) decreased as a result of feeding the meal of housefly larvae (by 21.9 and 13.7%) while the weight of inedible viscera increased (P < 0.05) after applications of both meals: by 16.9 and 22.0% in trial 1 and by 55 and 26.7% in trial 2.
Clarke, W. C. (1973). Sodium-retaining bioassay of prolactin in the intact teleost Tilapia mossambica acclimated to sea water. Gen Comp Endocrinol 21, 498-512.
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Clarke, W. C. (1973). Disc-electrophoretic identification of prolactin in the cichlid teleosts Tilapia and Cichlasoma and densitometric measurement of its concentration in Tilapia pituitaries during salinity transfer experiments. Can J Zool 51, 687-95.
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Clarke, W. C., Farmer, S. W., and Hartwell, K. M. (1977). Effect of teleost pituitary growth hormone on growth of Tilapia mossambica and on growth and seawater adaptation of sockeye salmon (Oncorhynchus nerka). Gen Comp Endocrinol 33, 174-8.
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Cockson, A. (1970). Some polysaccharides in the mucus-cells in the gills of Tilapia shirana chilwae Trewavas Pisces, Cichlidae). Cellule 68, 205-10.
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Colombo, L., Bern, H. A., Pieprzyk, J., and Johnson, D. W. (1972). Corticosteroidogenesis in vitro by the head kidney of Tilapia mossambica (Cichlidae, Teleostei). Endocrinology 91, 450-62.
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Cuvin-Aralar, M. L., and Aralar, E. V. (1993). Effects of long-term exposure to a mixture of cadmium, zinc, and inorganic mercury on two strains of tilapia Oreochromis niloticus (L.). Bull Environ Contam Toxicol 50, 891-7.
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Dadzie, S., and Hyder, M. (1976). Compensatory hypertrophy of the remaining ovary and the effects of methallibure in the unilaterally ovariectomized Tilapia aurea. Gen Comp Endocrinol 29, 433-40.
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Dange, A. D. (1986). Branchial Na+ -K+ -ATPase activity in freshwater or saltwater acclimated tilapia, Oreochromis (Sarotherodon) mossambicus: effects of cortisol and thyroxine. Gen Comp Endocrinol 62, 341-3.
The ability of cortisol to stimulate branchial Na+ -K+ -ATPase activity in tilapia was further augmented by thyroxine. The effects of hormonal treatments were greater in the saltwater acclimated fish than in the freshwater acclimated ones.
Dauder, S., Young, G., and Bern, H. A. (1990). Effect of hypophysectomy, replacement therapy with ovine prolactin, and cortisol and triiodothyronine treatment on prolactin receptors of the tilapia (Oreochromis mossambicus). Gen Comp Endocrinol 77, 378-85.
The effects of hypophysectomy and subsequent replacement therapy with ovine prolactin (oPRL) on specific binding of 125I-oPRL to gill, kidney, and liver membranes of male tilapia were examined. The possible control of prolactin receptors by cortisol (F) and triiodothyronine (T3) was also studied using intact animals. In gill and kidney, hypophysectomy resulted in a significant decrease in specific binding that was partially restored (threefold increase) by three injections of oPRL, suggesting a role of the pituitary in the control of prolactin receptors. However, removal of the pituitary and replacement therapy with oPRL had no effect on binding by liver membranes. Cortisol and T3 treatment, alone or in combination, did not significantly affect prolactin binding by any of the tissues tested.
Dauder, S., Young, G., Hass, L., and Bern, H. A. (1990). Prolactin receptors in liver, kidney, and gill of the tilapia (Oreochromis mossambicus): characterization and effect of salinity on specific binding of iodinated ovine prolactin. Gen Comp Endocrinol 77, 368-77.
Specific binding of 125I-ovine prolactin (oPRL) to microsomal fractions from gill, kidney, and liver of adult tilapia was determined. Specific binding varied among tissues, the highest values being displayed by kidney membranes. In the liver, the binding of oPRL was not strongly displaced by tilapia prolactins (tPRL177 and tPRL188), although tPRL177 was six times more potent than tPRL188. On the other hand, in kidney and gill membranes, the two tPRLs were equipotent. Tilapia PRLs showed low potency in competing for oPRL-binding sites when pregnant rat liver membranes were utilized. Tilapia growth hormone (tGH) and human growth hormone (hGH) displaced 125I-oPRL from liver as well as did tPRL177 but were not recognized well by renal or branchial receptors. Two 125I-oPRL- binding sites were detected in every tissue tested. These binding sites are subject to physiological regulation since adaptation to seawater resulted in a significant decrease in specific binding.
Davies, W., and Jackson, H. (1977). Chemosterilant action of niridazole on Tilapia mossambica (Sarotherodon mossambicus). Gen Pharmacol 8, 31-5.
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de la Fuente, J., Guillen, I., Martinez, R., and Estrada, M. P. (1999). Growth regulation and enhancement in tilapia: basic research findings and their applications [In Process Citation]. Genet Anal 15, 85-90.
Growth manipulation in fish is one of the targets of gene transfer experiments. The aim is to produce strains with improved growth performance. The transfer of growth hormone transgenes has been successful in many fish species. Now detailed knowledge of the molecular events that control growth in fish is necessary in order to efficiently manipulate this process. We have selected tilapia for our studies because these species are suitable for basic research as well as for the development of improved strains for aquaculture. Here we review the results of basic and applied research in the field of growth control and manipulation in tilapia. Our experiments produced new scientific results on growth control in tilapia. These results were used to develop a new aquacultured line with improved growth performance. Many of these results are probably applicable to other teleosts.
de la Fuente, J., Guillen, I., Martinez, R., and Estrada, M. P. (1999). Growth regulation and enhancement in tilapia: basic research findings and their applications. Genetic Analysis-Biomolecular Engineering 15, 85-90.
Growth manipulation in fish is one of the targets of gene transfer experiments. The aim is to produce strains with improved growth performance. The transfer of growth hormone transgenes has been successful in many fish species. Now detailed knowledge of the molecular events that control growth in fish is necessary in order to efficiently manipulate this process. We have selected tilapia for our studies because these species are suitable for basic research as well as for the development of improved strains for aquaculture. Here we review the results of basic and applied research in the field of growth control and manipulation in tilapia. Our experiments produced new scientific results on growth control in tilapia. These results were used to develop a new aquacultured line with improved growth performance. Many of these results are probably applicable to other teleosts. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
de Vera, M. P., and Pocsidio, G. N. (1998). Potential protective effect of calcium carbonate as liming agent against copper toxicity in the African tilapia Oreochromis mossambicus. Sci Total Environ 214, 193-202.
The lipid peroxidative effects of copper sulfate singly (4 mg/l CuSO4.5H2O) and in combination with calcium carbonate (4 mg/l CuSO4.5H2O + 50 mg/l CaCO3) were determined in the liver of the African tilapia Oreochromis mossambicus following exposures of the fish to the chemicals for 24, 48, 72, 96 and 168 h. Lipid peroxidative effects of the treatment with calcium carbonate (50 mg/l CaCO3) and with a known hepatotoxicant, carbon tetrachloride (0.25 ml/l CCl4) were also determined. Fish not exposed to any chemical served as negative controls. The extent of lipid peroxidation was based on hepatic malondialdehyde (MDA) levels as assayed using the thiobarbituric acid reaction test. Results suggested the lipid peroxidative property of the copper salt which was associated with the toxic nature of the heavy metal, although, this effect was not as potent as that of CCl4. Findings also indicated a measure of protection against copper hepatotoxicity provided by the addition of calcium carbonate as a liming agent in the water.
Delicio, H. C., and Vicentini-Paulino, M. L. (1993). 2-deoxyglucose-induced food intake by Nile tilapia, Oreochromis niloticus (L.). Braz J Med Biol Res 26, 327-31.
The alimentary and glycemic responses to cytoglycopenia were studied in thirty-one Nile tilapia alevins of indeterminate sex and age, measuring on average 10.67 +/- 0.82 cm. The cytoglycopenia was provoked by ip injection of 60 mg/kg 2-deoxy-D-glucose (2-DG, N = 16). The control group (N = 15) was submitted to ip injection of 0.2 ml saline. Blood samples for glucose determination were obtained before and three hours after drug administration by cardiac puncture. Food was then offered ad libitum. One hour later the animals were sacrificed and their stomachs removed. The difference in wet weight between full and empty stomach was utilized to quantify the food intake. Median food intake was 0.3877 g for the fish treated with 2-DG and 0.107 g for the animals injected with saline. This difference was statistically significant by the Mann- Whitney test (P 0.05). The median values of blood glucose levels before drug injection were 46.19 mg/100 ml in the 2-DG-treated fish and 44.54 mg/100 ml in the control group. Three hours after drug administration, the values were 48.64 mg/100 ml in the experimental group and 56.90 mg/100 ml in the control group. The difference between the values of blood glucose before and after the drug was not significant for either group. We conclude that glucoprivation provokes food intake in fish and that the same glucoprivation was not sufficient to provoke hyperglycemia.
Desai, A. K., Joshi, U. M., and Ambadkar, P. M. (1984). Histological observations on the liver of Tilapia mossambica after exposure to monocrotophos, an organophosphorus insecticide. Toxicol Lett 21, 325-31.
The histological changes in the liver of Tilapia mossambica were observed after exposure to a sublethal level (2.5 ppm) of monocrotophos. The changes observed after 2 days of exposure were characterized by necrosis and vacuolation of hepatocytes. Fatty degeneration was observed after 10 days of exposure. However, normalization of histological picture was evident after 15 days of treatment, though some patches of degenerating zones were also found to exist concomitantly. A wave of secondary intensively degenerative changes was observed from 30 days up to 45 days of experimentation. The possible significance of histological lesions and adaptation to exposure after sublethal doses as well as continuous exposure are discussed.
Dharmamba, M., Handin, R. I., Nandi, J., and Bern, H. A. (1967). Effect of prolactin on freshwater survival and on plasma osmotic pressure of hypophysectomized Tilapia mossambica. Gen Comp Endocrinol 9, 295-302.
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Dharmamba, M., and Nishioka, R. S. (1968). Response of "prolactin-secreting" cells of Tilapia mossambica to environmental salinity. Gen Comp Endocrinol 1, 409-20.
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Dharmamba, M. (1970). Studies of the effects of hypophysectomy and prolactin on plasma osmolarity and plasma sodium in Tilapia mossambica. Gen Comp Endocrinol 14, 256-69.
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Dharmamba, M., and Maetz, J. (1972). Effects of hypophysectomy and prolactin on the sodium balance of Tilapia mossambica in fresh water. Gen Comp Endocrinol 19, 175-83.
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Dharmamba, M., Mayer-Gostan, N., Maetz, J., and Bern, H. A. (1973). Effect of prolactin on sodium movement in Tilapia mossambica adapted to sea water. Gen Comp Endocrinol 21, 179-87.
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Dharmamba, M., Bornancin, M., and Maetz, J. (1975). Environmental salinity and sodium and chloride exchanges across the gill of Tilapia mossambica. J Physiol (Paris) 70, 627-35.
10 Freshwater-(FW)-adapted, one-third seawater (1/3 SW)-adapted and seawater (SW) adapted Tilapia mossambica were compared for their branchial Na+ influx and efflux as well as Cl- efflux. Na+ and Cl- effluxes were identical. Rates of effluxes were in 1/3 SW- and in SW- adapted fish 10 times and 200 times higher respectively than in FW specimens. 20 Shock due to handling and transfer to small experimental chambers induced, within 20 to 45 min., a considerable increase in Na+ efflux and a more discrete augmentation of the Na+ influx. 30 Branchial Mg++-and Na+-K+ activated ATPase activities increased significantly upon adaptation from FW to 1/3 SW. No significant increase was apparent upon adaptation from 1/3 SW to SW. 40 The trans-branchial potential observed in SW Tilapia resembled the pattern previously described in other species of teleosts.
Dharmamba, M., and Maetz, J. (1976). Branchial sodium exchange in seawater-adapted Tilapia mossambica: effects of prolactin and hypophysectomy. J Endocrinol 70, 293-9.
The effects of exogenous prolactin and hypophysectomy were tested on Na exchange across the gills of Tilapia mossambica adapted to sea-water. Exogenous prolactin produced a 75% decrease of both total Na influx and Na efflux. Total Na influx was measured simultaneously with the drinking rate. Water ingestion stopped almost completely in prolactin- treated fish. Thus branchial net excretion flux of Na was reduced 75% by prolactin. Hypophysectomy produced a 50% inhibition of Na efflux across the gill.
Dickson, B. C., Yang, H., Pohajdak, B., and Wright, J. R., Jr. (1998). Quantification of tilapia islets: a direct relationship between islet cell number and body mass. Transplant Proc 30, 621-2.
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Ding, J. L., Hee, P. L., and Lam, T. J. (1989). Differential susceptibility of a fish, tilapia Oreochromis mossambicus (Teleostei, Cichlidae) to hepatocarcinogenesis by diethylnitrosamine and methylazoxymethanol acetate. Carcinogenesis 10, 493-9.
Oreochromis mossambicus, commonly known as tilapia, is a freshwater teleost with a wide tolerance to environmental conditions. Multiple focal lesions in the liver were observed 2 months after cessation of a one-month long treatment with 100 p.p.m. diethylnitrosamine. Cells were small and compact and arranged in sheets. Ultrastructurally, these cells have abundant endoplasmic reticulum, round mitochondria, less conspicuous golgi apparatus and fat droplets. Other organs like the intestines, spleen, kidneys, ovaries and pituitary appeared normal. Two liver inducible enzymes, gamma-glutamyl transferase and tyrosine aminotransferase were elevated by 5- and 3-fold respectively. Aggressive migration of hepatocytes was observed in tumorigenic liver explants. Vitellogenesis and early embryological development appeared unaffected as the female fish spawned during hepatocarcinogenesis. However, their fry were stunted and short-lived. To compare the susceptibility of tilapia to another hepatocarcinogen, the fish were also treated with methylazoxymethanol acetate at 10 p.p.m. for 0.5-1 h. However, methylazoxymethanol acetate was too toxic and 75% of the fish succumbed 1 day after treatment. Moreover, after 2 months post- treatment, neither tumors nor change in enzyme activities were observed in any organ. These results suggest that tilapia could be a useful model for screening and differentiating carcinogens since they could develop liver tumors within only 2 months after treatment with diethylnitrosamine.
DiStefano, J. J., 3rd, Ron, B., Nguyen, T. T., Weber, G. M., and Grau, E. G. (1998). 3,5,3'-Triiodothyronine (T3) clearance and T3-glucuronide (T3G) appearance kinetics in plasma of freshwater-reared male tilapia, Oreochromis mossambicus. Gen Comp Endocrinol 111, 123-40.
Distribution and metabolism of the thyroid hormone 3,5, 3'-l- triiodothyronine (T3) were studied in several ways to gain insights into these processes in the warm water fish tilapia Oreochromis mossambicus. Trace doses of 125I-labeled T3 (T*3)1 were injected intraarterially, extraarterially, or intraperitoneally in freshwater- reared male tilapia to explore plasma clearance kinetic responses to these different input modalities. Multicompartmental analysis of the plasma clearance data indicated a kinetic distribution of T*3 much like that reported for the rat and human, with about 2% of total body T*3 in plasma, 5% in rapidly exchanging tissues such as kidney and liver, and 93% in slowly exchanging tissues such as muscle. However, plasma clearance rates (PCR, 5.37 mL/h . 100 g body wt) and plasma appearance rates (PAR3 = PCR x [T3] plasma = 36.3 ng/h . 100 g body wt) were quite different than these indices in rat and human and 5 to 50 times larger than values reported for rainbow trout. On a whole-body basis, normalized for body weight, the tilapia we studied produced and accumulated much more T3 than rat, human, or rainbow trout. Enzymatic and chromatographic analyses of the plasma clearance data samples indicated substantial production of labeled glucuronide, but not sulfate, conjugates of iodothyronines (TiG) of unknown origin appearing in plasma. The TiG appeared beginning a few hours postinjection, peaked at 6 hours, and yielded a predicted steady-state TiG level of 8.3% of the T3 level in plasma. In contrast, in published studies, no conjugates were detected in rainbow trout plasma from 2 to 24 h after iv injection of T*3, T*4, or reverse-T*3, although conjugates of all were present in bile. To our knowledge, although T3 and T4 sulfate conjugates are present in the sera of several mammals, this is the first quantification of iodothyronine glucuronides reported in blood of any species under normal conditions. This might have physiological significance for the tilapia, with T3G providing a reversible storage form of T3 in blood, as has been suggested for sulfate conjugates of T3 and T4 in blood of several mammals. Copyright 1998 Academic Press.
Drakenberg, K., Sara, V. R., Lindahl, K. I., and Kewish, B. (1989). The study of insulin-like growth factors in Tilapia, Oreochromus mossambicus. Gen Comp Endocrinol 74, 173-80.
Whole and acid-separated serum samples from fed, starved, and refed Tilapia were analyzed for insulin-like growth factors 1 (IGF-1) and 2 (IGF-2) using human fetal brain radioreceptorassay (RRA-IGF-1), rat liver membrane radioreceptorassay (RRA-IGF-2), and radioimmunoassay (RIA-IGF-1). Triidothyronine (T3) and thyroxine (T4) levels were measured by commercial kits for RIA. For serum separation, acid Sephadex G-50 and G-100 and neutral Sephadex G-200 columns were used. Whole serum and separated serum cross-reacted in RRA-IGF-1, but only slightly in RRA-IGF-2. IGF activity eluted in two peaks after acid G-50 chromatography. Peak I eluted at the void volume, and peak II eluted with an apparent molecular weight of approximately 7 kDa. The 7 kDa activity did not cross-react in RIA-IGF-1 excluding identity with human intact or truncated IGF-1, but did suggest the presence of an IGF-1 variant form. Whole serum was separated over a neutral G-200 column, and all activity eluted at the void volume indicated an apparent molecular weight equal to or greater than 250 kDa. No IGF-binding activity was displayed by either whole serum or peak I after acid G-50 chromatography. Despite significant changes in body weight, an influence of starvation and refeeding on serum IGF activity could not be established. No correlation was seen between serum IGF and T3 and T4 levels.
du Preez, H. H., and van Vuren, J. H. (1992). Bioconcentration of atrazine in the banded tilapia, Tilapia sparrmanii. Comp Biochem Physiol C 101, 651-5.
1. The bioconcentration of atrazine was determined in the liver, muscle, heart, gonads and brain of Tilapia sparrmanii exposed to high concentrations of atrazine. 2. The highest concentrations were recorded in the ovaries (50.6 micrograms/g) and in the liver (40.1 +/- 5.5 micrograms/g). This may be attributed to the higher lipid content of these organs, while the liver also accumulates atrazine as a result of its detoxification function. 3. The bioaccumulation factors for atrazine in the liver, muscle, heart, gonads and brain ranged from 0.9 to 20.0. Bioconcentration of atrazine in banded tilapia was found to be low, even after exposure to external atrazine concentration much higher than detected in natural surface water.
du Preez, H. H., van Rensburg, E., and van Vuren, J. H. (1993). Preliminary laboratory investigation of the bioconcentration of zinc and iron in selected tissues of the banded tilapia, Tilapia sparrmanii (Cichlidae). Bull Environ Contam Toxicol 50, 674-81.
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Duponchelle, F., Cecchi, P., Corbin, D., Nunez, J., and Legendre, M. (1999). Spawning season variations of female Nile Tilapia, Oreochromis niloticus, from man-made lakes of Cote D'Ivoire. Environmental Biology of Fishes 56, 375-387.
The spawning season of Oreochromis niloticus females was studied over two annual cycles in 6 small agropastoral and 2 large hydroelectric reservoirs of Cote d'Ivoire (Ayame and Kossou), situated between 5 and 10 degrees N of latitude. Reproduction occurred during a marked season in the agropastoral reservoirs and in Lake Ayame, whereas it was continuous in Lake Kossou. Spawning season differed between reservoirs and among years within the same reservoir. Seasonal changes in temperature, rainfall, day length, chlorophyll a concentration and water level often corresponded with changes in the annual spawning cycle. However, annual periodicity of O. niloticus reproduction was more likely influenced by the ephemerides cycle.
Eckstein, B. (1970). Metabolic pathways of steroid biosynthesis in ovarian tissue of a teleost, Tilapia aurea. Gen Comp Endocrinol 14, 303-12.
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Eckstein, B., and Katz, Y. (1971). Steroidogenesis in post- and pre-spawned ovaries of a cichlid fish, Tilapia aurea. Comp Biochem Physiol A 38, 329-38.
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Edery, M., Young, G., Bern, H. A., and Steiny, S. (1984). Prolactin receptors in tilapia (Sarotherodon mossambicus) tissues: binding studies using 125I-labeled ovine prolactin. Gen Comp Endocrinol 56, 19-23.
The binding of 125I-labeled ovine prolactin (oPRL) to membrane preparations of tissue from freshwater-adapted tilapia (Sarotherodon mossambicus) was examined. Liver, ovary, and testis showed a relatively high specific binding (5-10%). A lower specific binding occurred consistently in intestine and gill tissue, and inconsistently in urinary bladder and kidney preparations. Desaturation experiments with MgCl2 indicated that a majority of the PRL receptors were already occupied by endogenous PRL. Scatchard analysis of liver binding gave a dissociation constant of 0.6 X 10(-9) M and a capacity of 207 fmol/mg protein.
El Gamal, A. R. A., Davis, K. B., Jenkins, J. A., and Torrans, E. L. (1999). Induction of triploidy and tetraploidy in Nile tilapia, Oreochromis niloticus (L.). Journal of the World Aquaculture Society 30, 269-275.
Induction of triploidy and tetraploidy in Nile tilapia, Oreochromis niloticus, was investigated by heat shock, cold shock, hydrostatic pressure, and/or chemicals (cytochalasin A, B, and D). Additionally, efficacy of combined protocols was determined. Heat shock 10 min after fertilization induced triploidy when incubation temperature was 24 C but not when incubation temperature was 31 C. Heat shock of 40-41 C at 4-6 min after fertilization was effective in inducing up to 100% triploidy with hatchability similar to controls. Cold shock at 13 C for 45 min five min after fertilization induced 85-100% triploids. Heat shock and multiple heat shocking were the most effective treatments for the induction of tetraploidy. Two heat treatments of 41 C applied at 65 and 80 min after fertilization for 5 min each produced approximately 80% tetraploidy in hatched fry. Immersion of fertilized eggs in cytochalasin A, B, or D at concentrations up to 10 mu g/L applied at various times and durations was ineffective in inducing triploidy or tetraploidy.
el Safi, S. H., Haridi, A. A., and Rabaa, F. M. (1985). The food of the larvivorous fish Gambusia affinis (Baird and Girard) and Oreochromis (formerly Tilapia) niloticus (Linnaeus) in Gezira irrigation canals. J Trop Med Hyg 88, 169-74.
The food of both Gambusia affinis and Oreochromis niloticus was studied. Organisms eaten by both species of fish are tabulated, together with the amounts eaten during the various months of the year. G. affinis larger than 25 mm are carnivorous and become more so with age. Food selection by G. affinis depends on the availability of food items rather than choice. It showed a marked preference for mosquito larvae. O. niloticus smaller than 150 mm were markedly carnivorous, but this decreased with age. Only small fish of this species are useful for the biological control of mosquitoes. Fish larger than 150 mm showed a marked preference for higher aquatic macrophytes.
el-Bedawey, A. E., el-Sherbiny, A. M., Zaki, M. S., and Khalil, A. H. (1985). The effect of certain antibiotics on the keeping quality of bolti fish (Tilapia nilotica). Nahrung 29, 665-70.
Fresh bolti fish (Tilapia nilotica), caught in the river Nile was immersed in 10 and 20 ppm tetracycline (TC) solutions for 10 and 15 min respectively and in 500 and 1000 R.U. nisin/g fish for 20 and 30 min respectively. Total volatile bases (TVN) showed in both fish treated with TC and nisin a slow increase at the first stage and after that a fast increase. There was an increase in trimethylamine (TMA) during the storage period, but the fish treated with TC and nisin contained less TMA than the control. Starting from 6 h the residual TC decreased gradually till the third day, when it disappeared completely. There is no change in pH values in both control and treated fish. Optical density (OD) of gills extract increased gradually as the storage period progresses. The treated fish showed lower OD values than the controls. The refractive index of muscle fluids and the OD of muscle extract showed no significant differences between the control and treated fish.
el-Bedawey, A. E., Zaki, M. S., el-Sherbiney, A. M., and Khalil, A. H. (1985). The effect of certain antibiotics on bolti fish (Tilapia nilotica) preservation. Nahrung 29, 303-8.
The shelf life of bolti fish (Tilapia nilotica) caught in the river Nile, has been successfully prolonged for about 9 days by dipping in tetracycline (TC) or nisin solution followed by refrigeration, although the initial microbial contamination in the fresh fish was very high. The caught fish were gutted and treated with 10 and 20 ppm TC solutions for 10 and 15 min by dipping, and with 500 and 1000 R.U. nisin/g fish for 20 and 30 min. The treated and control fish samples, were stored and refrigerated at (4 +/- 1) degree C for 12 days. Total bacterial counts, the most probable number of coliform bacteria and lactic acid bacteria in the fish treated with TC or nisin, were lower than those of the control, especially at 20 ppm TC, 15 min dipping, and 1000 R.U. nisin/g, 30 min. Further more TC was more effective against yeasts and moulds. This result suggest that antibiotics would help in transporting chilled fish from the highdam lake in Aswan to Cairo (about 900 km). According to the present results it may be recommended to use the antibiotic TC, with the concentration of 20 ppm for 15 min dipping, for prolonging the shelflife of bolti fish. The presence and increase of coliform bacteria in fish, draw the attention to the necessity of hygienic measures when dealing with such fish until to the consumption.
El-Demerdash, F. M., and Elagamy, E. I. (1999). Biological effects in Tilapia nilotica fish as indicators of pollution by cadmium and mercury. International Journal of Environmental Health Research 9, 173-186.
Fish samples of Tilapia nilotica obtained from Lake Maryout were used to investigate the relationship between heavy metals and biological effects due to the industrial contaminations in the lake. Samples were examined for the activities of acetylcholinesterase, alkaline phosphatase and glutathione S- transferase. Meanwhile, levels of cadmium (Cd) and mercury (Hg) were determined in both fish and water. Also, the electrophoretic patterns of proteins were presented as well as the amino acid composition of fish proteins. Results obtained revealed that the activities of all studied enzymes were markedly inhibited. Maryout samples contained higher concentrations of Hg and Cd than Nozha samples. Marked differences in electrophoretic patterns of proteins prepared from Maryout and Nozha fish samples were found. The nutritional quality of Maryout fish proteins was lower than that of Nozha samples due to the lower content of essential amino acids. Results obtained from field and laboratory exposures can give a useful indication for a proper use of biochemical responses as biomarkers in monitoring heavy metal pollution.
El-Dib, M. A., El-Elaimy, I. A., Kotb, A., and Elowa, S. H. (1996). Activation of in vivo metabolism of malathion in male Tilapia nilotica. Bull Environ Contam Toxicol 57, 667-74.
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el-Elaimy, I. A., Sakr, S. A., el-Saadany, M. M., and Gabr, S. A. (1993). Electron microscopic study of the liver of Tilapia nilotica exposed to neopybuthrin. Bull Environ Contam Toxicol 50, 682-8.
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el-Gendy, K. S., Aly, N. M., and el-Sebae, A. H. (1998). Effects of edifenphos and glyphosate on the immune response and protein biosynthesis of bolti fish (Tilapia nilotica). J Environ Sci Health B 33, 135-49.
The effects of 1/1000 field recommended concentration of the organophosphorus compounds; edifenphos and glyphosate on the immune response and protein contents were investigated after different time intervals. The cell mediated immune response assessed by proliferative response of splenocytes to mitogens; phytohemagglutinin (PHA) and concanavalin A (Con A) for T cell and lipopolysaccharide (LPS) for B cell decreased significantly in tems of the level of stimulation index in the treated fish and reached maximal depression after 4 weeks. Humoral immunity assessed as splenic antibody plaque forming cells (PFC) measured after 5 days in vitro immunization to sheep erythrocytes (SRBC's) were suppressed in a concentration dependent pattern by the two compounds. The estimated ED50 for the PFC/10(6) cells of edifenphos and glyphosate were 1.48 x 10(-2) uM and 1.65 x 10(-2) uM respectively. The data also showed that serum antibody titres in the treated fish were decreased in a time dependent manner. The total protein content of serum treated with the two pesticides was decreased after different time periods compared with control. The blood serum of treated and untreated Tilapia nilotica were analyzed electrophoretically for protein components and the percentage of proteins in each fraction was determined.
el-Sayed, M. M., Ezzat, A. A., Kandeel, K. M., and Shaban, F. A. (1984). Biochemical studies on the lipid content of Tilapia nilotica and Sparus auratus. Comp Biochem Physiol [B] 79, 589-94.
Seasonal variations of total lipids, free fatty acids, triglycerides, phospholipids and cholesterol content of the freshwater fish Tilapia nilotica and the marine fish Sparus auratus were investigated. Male fish of S. auratus showed higher muscular and hepatic total lipids and hepatic free fatty acids than those of T. nilotica (P less than 0.05). The mean differences in gonadal male lipids of the two species were not significant. Tilapia nilotica female fish showed a significantly higher content of hepatic free fatty acids, phospholipids and cholesterol (P less than 0.01, 0.01, 0.05 respectively) and gonadal total lipids, triglycerides, and cholesterol (P less than 0.05) than those of S. auratus females. In contrast S. auratus females exhibited higher muscular total lipids, triglycerides, phospholipids and cholesterol content (P less than 0.01, 0.05, 0.02, 0.05, respectively) and gonadal phospholipids (P less than 0.05) than those of the T. nilotica females. In general hepatic and gonadal lipids of freshwater fish T. nilotica were higher than those of the marine fish S. auratus, and in contrast the marine fish contained higher muscular lipids than the freshwater fish.
El-Sayed, A. F. M. (1999). Alternative dietary protein sources for farmed tilapia, Oreochromis spp. Aquaculture 179, 149-168.
Tilapia are widely cultured in the tropical and subtropical regions of the world and constitute the third largest group of farmed finfish, only after carps and salmonids, with an annual growth rate of about 11.5%. Global production of farmed tilapia has increased more than three-fold since 1984, from 186,544 m to 659,000 m, representing about 4.48% of total farmed finfish in 1995, with a value of US$925 million. Feeding represents over 50% of the operational costs of aquaculture. The shortage in world production of fish meal (the main conventional protein source), coupled with increased demand for fish meal in feeds for livestock and poultry is likely to reduce the dependence on fish meal as a single protein source in aquafeeds. Therefore, fish nutritionists have made several attempts to partially or totally replace fish meal with less expensive, locally available protein sources. The present review presents alternative dietary protein sources for tilapia, with emphasis on fishery by-products, terrestrial animal by-products, oilseed plants, aquatic plants, single cell proteins, grain legumes, plant protein concentrates and cereal by-products. The nutritive values, inclusion levels, constraints and economic evaluation of these sources are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.
El-Sharouny, H. M., and Badran, R. A. (1995). Experimental transmission and pathogenicity of some zoosporic fungi to Tilapia fish. Mycopathologia 132, 95-103.
Seventeen fungal species belong to sex genera were recovered from the four organs of Tilapia fish and the most common were Saprolegnia ferax, S. diclina, Achlya dubia, A. americana, A. racemosa and A. flagellata, Dictyuchus sterile, Pythium undulatum and Aphanomyces sp. Severe infection followed by death of all fish was incited by S. parasitica and S. ferax through experiment I. 30-70% of T. nilotica and T. galileae were killed through experiment II by S. parasitica and S. ferax. T. galileae was more susceptible to fungal infection than T. nilotica.
el-Zanfaly, H. T., and Ibrahim, A. A. (1980). Boulti (Tilapia nilotica Linn.) fish paste. 2. Bacteriological studies of the raw fish and the produced paste. Z Ernahrungswiss 19, 163-5.
Total viable bacterial count reached 10(9) per gram of raw fish. It was decreased to 10(7) in fish paste and increased to 10(8)-10(9) after storage at 2-4 degrees C for 5 weeks. It was observed that fish paste showed higher counts when preserved in polyethylene bags than in aluminum tubes.
El-Zanfaly, H. T., and Ibrahim, A. A. (1982). Occurrence of bacterial pollution indicators in Boulti (Tilapia nilotica Linn.) fish. Z Ernahrungswiss 21, 246-53.
A study was made for the occurrence of colifor