Genetic parameters for survival during the grow‐out period in the GIFT strain of Nile tilapia (Oreochromis niloticus) and correlated response to selection for harvest weight |
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| Authors: | Azhar Hamzah Wagdy Mekkawy Hooi Ling Khaw Nguyen Hong Nguyen Hoong Yip Yee Khairul Rizal Abu Bakar Siti Azizah Mohd Nor Raul W Ponzoni |
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| Institution: | 1. School of Biological Sciences, University Science Malaysia, Minden, Penang, Malaysia;2. National Prawn Fry Production & Research Center, Kota Kuala Muda, Kedah, Malaysia;3. World Fish, Penang, Malaysia;4. Faculty of Agriculture, Animal Production Department, Ain Shams University, Cairo, Egypt;5. School of Science, Education and Engineering, University of the Sunshine Coast, Maroochydore, QLD, Australia;6. Facultad de Agronomia, Departamento de Produccion Animal, Universidad de la República, Montevideo, Uruguay |
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| Abstract: | The aims of this study were the estimation of genetic parameters for survival rate from tagging until harvest and the evaluation of the correlated response in survival rate to selection for harvest weight in the genetically improved farmed tilapia (GIFT) strain. The heritability for survival rate was low (0.038), and so was its genetic correlation with harvest weight (0.065), suggesting that selecting for the latter trait would have had no effect on survival. The calculation of the probability of survival by spawning season and line, fitting a model that included the random effects of individual animal and common environment, confirmed this prediction. There were very small and variable between line differences in the probability of survival, which generally favoured the selection line. We conclude that the focus of the GIFT programme on improving harvest weight was not detrimental to the survival of the fish during the grow‐out phase. |
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| Keywords: | survival
GIFT
heritability genetic correlation selection response |
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