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Santos A.I.,State University of Maringa | Nguyen N.H.,Worldfish Center | Nguyen N.H.,University of The Sunshine Coast | Ponzoni R.W.,Worldfish Center | And 3 more authors.
Aquaculture Research | Year: 2014

The strain by nutrition interaction in body weight and survival rate was examined by testing three genetic groups (Selection and Control lines of the GIFT strain, and Red tilapia) at two levels of protein in the diet (28% and 34%). The GIFT strain of Nile tilapia (Oreochromis niloticus) has been selected for high-breeding values for body weight, whereas the Control was contemporaneously maintained and selected for breeding values of body weight close to the population mean. The Red tilapia (Oreochromis spp) was unselected at the time of the experiment. There were a total of 6000 fish at stocking in the study (2000 fish per genetic group). During the grow-out period of 147 days, within each genetic group, the fish were randomly assigned to either a 28% or a 34% protein diet. Survival rate during grow-out averaged 72%. A total of 4335 fish were harvested, with individual body measurements and survival recorded. The effect of genetic group accounted for the largest proportion of variation in body weight and survival, followed by sex and protein level. Across the two dietary protein levels, the GIFT strain had the highest growth. The difference in body weight between the Control and Red tilapia was not statistically significant (P > 0.05). Responses in growth to dietary protein levels also differed between genetic groups. No differences (P > 0.05) in body weight were found in the GIFT selection and Control fish fed 28% or 34% protein diets. However, body weight of Red tilapia was greater in the high- than in the low-protein diet. In contrast to body weight, survival rate from stocking to harvest was affected by protein level. The high-protein diet significantly improved survival rate, averaging 24% across the three strains. The overall results indicate significant effects of genetic group and dietary protein level on both body weight and survival rate; however, the interaction between strain and dietary protein levels was small and possibly unimportant for these traits. It is concluded that the 28% protein diet used in the selection programme for the GIFT strain results in the selection of genotypes that can perform well under commercial feeds. © 2012 John Wiley & Sons Ltd. Source


Lind C.E.,WorldFish | Safari A.,WorldFish | Agyakwah S.K.,CSIR Water Research Institute | Attipoe F.Y.K.,CSIR Water Research Institute | And 11 more authors.
Aquaculture Reports | Year: 2015

Abstract Many tilapia (Oreochromis spp.) farmers produce all-male populations because of the superior growth rate of males compared to females. To investigate differences in body weight at harvest of males and females among different tilapia strains, we analyzed data from 62,787 individuals collected from pedigreed breeding programs of O. niloticus (GIFT from Malaysia, the Abbassa line from Egypt, and the Akosombo line from Ghana), O. shiranus (the Bunda College-Domasi selection line), O. aureus (a selection line under development in Abbassa, Egypt, and a selection line from Israel) and a synthetic selection line of Red tilapia under development in Jitra, Malaysia, derived from stock from Malaysia, Taiwan and Thailand (O. sp.). Mixed models were separately fitted to the data from each selection line. There was a significant sex effect in all strains (P < 0.001). A significant (P < 0.001) sex by generation interaction was observed in all strains (scale effect, not reversal of rankings), except Red tilapia and O. shiranus. Least squares means showed a large range in the magnitude of body weight differences between sexes across the seven strains. The largest percentage difference between females and males was in O. aureus from Egypt (female body weight was 52.2% that of males at harvest), whereas the smallest difference was observed in the GIFT strain of O. niloticus (female body weight 84.7% that of males). Female to male body weight percentages for Red tilapia, O. shiranus, Egypt O. niloticus, Israeli O. aureus and Ghana O. niloticus were 81.3, 81.0, 69.1, 61.7 and 61.0, respectively. We discuss the results in relation to the potential productivity improvements due to superior growth rates of all-male culture compared to mixed-sex culture in tilapia populations differing in the female to male body weight ratio. © 2015 The Author. Source


Nguyen N.H.,Worldfish Center | Ponzoni R.W.,Worldfish Center | Yee H.Y.,Worldfish Center | Abu-Bakar K.R.,Worldfish Center | And 2 more authors.
Aquaculture | Year: 2010

The quantitative genetic basis of fatty acid composition was examined in the Genetically Improved Farmed Tilapia (GIFT) strain of Nile tilapia selected for high breeding value for body weight and in the contemporaneous control selected for average breeding value. Gas chromatography analysis of 514 frozen fillet samples, obtained from the offspring of 104 sires and 154 dams from two generations in 2006 and 2007, showed that the fish possess all important fatty acids (FA), with the amount of omega-3 polyunsaturated fatty acids being 3.6%. The ratio of unsaturated to saturated fatty acids was greater than one (1.4) in the GIFT fillets, which is in line with the current dietary recommendation. Genetic analysis of FA was combined with 5532 performance and fillet records, and 2000 fillet samples analyzed for flesh composition and flesh quality attributes. A restricted maximum likelihood method applied to bivariate or trivariate mixed model was carried out in a full pedigree comprising a total of 18,970 animals to estimate genetic parameters and correlated responses in FA composition to the selection program. The estimates of heritability for individual FA varied from zero to medium, suggesting that FA composition of the GIFT fillet can respond to selection. Genetic correlations among FA within the same group (saturated, monounsaturated or polyunsaturated FA) were generally synergetic, but were antagonistic between groups. There were also both favourable and unfavourable genetic associations between important high chain polyunsaturated fatty acids and performance, fillet and flesh quality traits. Correlated changes in FA composition were measured by comparing least square means of the selection and control lines. Overall, selection for high growth resulted in very little change in FA composition. One notable change was that the content of heptadecanoic acid (C17:0) decreased in the selection relative to control line, which is beneficial for human health. In summary, the set of genetic parameters estimated and the response realized in the GIFT strain indicate that FA composition of tilapia or fish in general can be altered by genetic means. © 2010 Elsevier B.V. Source


Nguyen N.H.,Worldfish Center | Ponzoni R.W.,Worldfish Center | Abu-Bakar K.R.,Worldfish Center | Hamzah A.,National Prawn Fry Production and Research Center | And 2 more authors.
Aquaculture | Year: 2010

A data set consisting of 5532 slaughter records collected over three generations from a selection program for increased harvest body weight in the GIFT strain of Nile tilapia (Oreochromis niloticus) was used to estimate genetic parameters and correlated responses in body (live weight, standard length, body width and body depth) and carcass (fillet weight and fillet yield) traits. A multi-trait model using restricted maximum likelihood method was applied to a full pedigree comprising a total of 18,970 animals. The estimates of heritability for body and carcass traits were of moderate magnitude (0.20 to 0.33). The proportions of variance explained by the maternal and common environmental effects were small, ranging from 4 to 8% for body traits and fillet weight, but were negligible for fillet yield. Genetic correlations among body traits were high (0.78 to 0.95), except between standard length and body width (0.56). High genetic correlations (0.78 to 0.96) were also obtained between body traits and fillet weight, whereas those between body traits and fillet yield were generally low (0.35 to 0.44). Genetic changes were measured as the difference in least squares means between the selection and control lines. The correlated increase in fillet weight was 23% in the latest generation studied or 0.97 phenotypic standard deviation units (σP). The correlated response in fillet yield was negligible. In conclusion, selection for high growth significantly increased fillet weight. Strategies for the improvement of fillet yield in the GIFT strain are discussed. © 2010 Elsevier B.V. Source


Hamzah A.,Universiti Sains Malaysia | Hamzah A.,National Prawn Fry Production and Research Center | Nguyen N.H.,Worldfish Center | Nguyen N.H.,University of The Sunshine Coast | And 7 more authors.
Aquaculture Research | Year: 2016

The effect of selection for greater growth rate in the GIFT strain on traits related to female reproduction (weight at spawning, number of eggs, number of fry, total weight of fry and number of dead fry) was studied. Available records comprised 10 generations of data from a total of 935 breeding females with known pedigree. Female body weight at spawning was 255 g, whereas the averages for number of eggs, number of live fry at hatching, number of dead fry and total fry weight per spawning were 1444, 908, 64.90, and 7.24 g respectively. Heritabilities for reproductive traits were low to moderate (0.20 for number of eggs, 0.16 for number of hatched fry and 0.11 for fry weight per female at spawning). The genetic correlations between female body weight at spawning and reproductive traits were very low to low (0.01 to 0.31) and not significantly different from zero. The genetic correlations among reproductive traits (i.e. number of eggs, number of hatched fry and fry weight) were high (0.75 to 0.92). Phenotypic correlations were consistent with the genetic correlations, ranging from 0.56 to 0.85. Correlated responses in reproductive traits measured as differences in least squares means between Selection and Control lines were positive and significant (except for the number of dead fry) when age of females at spawning was fitted as a covariate. However, there were no significant differences in all studied traits when body weight of the female at spawning was fitted as a covariate within lines. This indicates that the greater reproductive rate was due to the greater size of females in the Selection line, but the efficiency of reproduction per unit weight of female did not change as a consequence of selection for growth. © 2016 John Wiley & Sons Ltd. Source

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