Optimization of 17α-methyltestosterone dose to produce quality mono-sex Nile tilapia Oreochromis niloticus

The 17α-methyltestosterone is the most common synthetic hormone used in male mono-sex production of Nile tilapia, Oreochromis niloticus. The current research aimed at finding out the most effective dose of 17α-methyltestosterone to produce quality Nile tilapia fry. Soon after absorbing the yolk sac, Nile tilapia fry was fed with a mixture of commercial fish feed and 17α-methyltestosterone for 28 days. Five doses of 17α-methyltestosterone, i.e., 0 mg, 50 mg, 60 mg, 70 mg, and 80 mg per kg feed, were used to treat tilapia that has been reared for additional 90 days to compare sex reversal, development, and survival rates. Both gonad histology and Squash test were performed to expose the sex percentage of O. niloticus accurately. The highest male 94.44% was obtained at 60 mg 17α-MT/kg feed dose followed by 91.67%, 88.89%, 86.11%, and 47.22% at 70, 80, 50, and 0 mg 17α-MT/kg feed dose. The groups treated with 17α-methyltestosterone hormone showed superior growth performance in comparison to the control group. The highest weight (14.62 ± 0.59 g) and length (92.18 ± 3.01 mm) were found at 60 mg dose whereas the lowest weight (8.64 ± 0.38 g) and length (70.17 ± 3.75 mm) were in the control group. The group given 60 mg 17α-MT feed represented the highest survival rate (84.10%) among other hormone-treated groups. The study disclosed that 60 mg 17α-MT/kg feed might be treated as the optimal dose for producing quality mono-sex male tilapia in the commercial hatchery.