Effects of 17-Alpha Methyl testosterone on survival of tilapia (Oreochromis mossambicus)

Objective: In the present study, effect of different dose rates of synthetic androgen 17 alpha methyl testosterone (MT) i.e. 50, 75 and 100 MG of hormone in per kg of feed, on sex reversal, growth performance and mortality of Mozambique tilapia was evaluate. Also, we studied affect of hormone on percent of survival. Method & Materials: MT was administrated orally by using pellet dry starter and Ethanol Alcohol, diet to tilapia fry for 21 days in glass aquaria. The fry also were kept 2 weeks after feeding to monitor its growth performance, at the End of experiment the sex ratio was determined by examining gonads after dissecting the fish. Growth performance was monitored by recording the morphometric characteristics; mortality was monitored by recording, i.e. wet body weight and total length of fish on start of feeding End of feeding and two weeks after feeding. Results & Conclusion: The results of the present study showed that all MT receiving treatment showed a significantly higher male proportion than control. No significant difference was between control group, dose 50 and dose 75 but survival in dose 100 mg/kg MT was significantly higher than other groups. Control group gave 51.96% male population and 0.95% mortality. Dose rate of 50 mg/kg of MT showed 74.29% male population and 0% mortality. Dose rate of 75 Mt mg/kg of feed resulted in maximum male population (98.09%) with 1.1% sterilized fish. Mortality in this group was 0%. Dose rate of 100 mg/kg hormone showed 79.38 % male population, 20.61% sterilized fish with 7.62% mortality.

کلیدواژه ها:

feeding method ، tilapia fry ، sterilized ، male ، female fishes ، dose rate ، mortality