Comparative Performance of Mixed-Sex and Hormonal-Sex-Reversed Nile Tilapia Oreochromis Niloticus and Hybrids (Oreochromis Niloticus × Oreochromis Urolepis Hornorum) Cultured in Concrete Tanks
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Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
Springer Link
Abstract
Uncontrolled breeding and precocious maturity in Nile tilapia, Oreochromis niloticus can be avoided by using all-male population. This study compared the growth performance, survival rate, condition factor and final fish tank biomass (yield) of mixed-sex and hormonal-sex-reversed O. niloticus and hybrids (O. niloticus × O. urolepis hornorum) cultured in tanks. Sex-reversed males were produced by feeding newly hatched fry with a diet containing 60 mg of 17α-methyltestosterone for 28 days. Fourteen O. niloticus with initial mean weight (±standard error) of 0.50 ± 0.04, 0.48 ± 0.06 and 0.46 ± 0.01 g for mixed-sex, sex-reversed and hybrids, respectively, were separately stocked in triplicate tanks at a density of two fish m−2 and fed a 300 g kg−1 crude protein diet for 12 weeks. Results showed that hybrids had significantly higher final mean weight (31.41 ± 0.33 g) than hormonal-sex-reversed (25.82 ± 1.51 g) and mixed-sex O. niloticus (19.50 ± 1.26 g; p < 0.05). Similarly, sex-reversed O. niloticus had significantly higher final mean weight than mixed-sex (p < 0.05). The condition factor of hybrids (1.71 ± 0.05) was significantly higher than that of sex-reversed (1.46 ± 0.01; p = 0.001) and mixed-sex O. niloticus (1.43 ± 0.01; p = 0.001). Survival rate was not significantly different among treatments (p = 0.445). The final fish tank biomass was significantly higher in hybrids (535.24 ± 31.67 g tank−1) and hormonal-sex-reversed (486.52 ± 33.70 g tank−1) than mixed-sex O. niloticus (330.05 ± 17.08 g tank−1; p < 0.05). This study demonstrates that hybrids have superior growth performance and condition factor than sex-reversed and mixed-sex but have similar yields to hormonal-sex-reversed O. niloticus. These results suggest that O. niloticus farmers can improve growth rate and yield by rearing hybrids without affecting survival rate.
Description
Keywords
All-male tilapia, Precocious maturity, Heterosis, Androgenic effect, Anabolic effect
Citation
Mbiru, M., Limbu, S.M., Chenyambuga, S.W., Lamtane, H.A., Tamatamah, R., Madalla, N.A. and Mwandya, A.W., 2016. Comparative performance of mixed-sex and hormonal-sex-reversed Nile tilapia Oreochromis niloticus and hybrids (Oreochromis niloticus× Oreochromis urolepis hornorum) cultured in concrete tanks. Aquaculture International, 24(2), pp.557-566.