COMPARISON OF IMMERSION AND ORAL ADMINISTRATION OF 17Α-METHYLTESTOSTERONE HORMONE ON MALE SEX RATIO OF NILE TILAPIA (Oreochromis niloticus)

Abstract

Nile tilapia (Oreochromis niloticus) is one of the most important freshwater aquaculture commodities. The production of all-male populations is considered beneficial due to the faster growth rate of male fish. This study aimed to compare the effectiveness of immersion and oral administration of 17α-methyltestosterone (MT) hormone on male sex ratio in Nile tilapia. A Completely Randomized Design (CRD) consisting of five treatments and three replications was used: P0 (control), P1 (immersion MT 2 mg/L), P2 (oral MT 50 mg/kg feed), P3 (oral MT 60 mg/kg feed), and P4 (oral MT 70 mg/kg feed). Seven-day-old larvae were reared for 50 days. Parameters observed included male sex ratio, survival rate, weight gain, length gain, specific growth rate, and water quality. The results showed that MT treatment significantly increased the percentage of male fish compared to the control. The highest male percentage was observed in P4 (87.8%), followed by P1 (86.7%), P3 (76.7%), and P2 (72.2%), while the control produced only 52.2% males. Hormonal treatments had no significant effect on survival rate, weight gain, length gain, or specific growth rate (P>0.05). It can be concluded that both immersion and oral administration methods were effective in increasing male sex ratio in Nile tilapia with relatively similar effectiveness.