The present study was conducted to examine the ability of papaya (Carica papaya) seeds in reducing the reproductive performance of Nile tilapia through gonadal sterilization. In the first phase, 9 days fry of Nile tilapia were reared in 50-L size aquaria and fed with normal feed (T1) and papaya seed powder mixed feed @ 50 (T2), 100 (T3), and 150 (T4) g/kg diet at the rate of 5 percent of body weight for 30 days. After 30 days of treatment, 50 fish from each group were reared in outdoor hapa for 6 months with normal feed, and gonadal status was observed. In the second phase, matured fish from both the control and papaya seed treated group (T4@150 g/kg diet) were reared in two separate hapas for the next 3 months to observe their reproductive performance. Results showed that papaya seed feeding had no adverse effect on growth, survival, and water quality during the treatment period. The gonadosomatic index of both males and females was significantly lower in the papaya seed treated group (0.1±0.0 percent) than control (0.2±0.01 percent). The number of fish spawned per week was significantly lower in the papaya seed treated group (1.2±0.2) compared to the control group (3.6±0.3). The number of eggs per g female was significantly lower in the papaya seed treated group compared to the control group. The fertilization rate was significantly lower in the papaya seed treated group (93.6±1.1 percent) compared to the control group (98.2±1.3 percent) (P˂0.05). This study demonstrated that feeding papaya seeds at the dose of 150 g/kg diet (15 percent) can reduce the reproductive performance of Nile tilapia.
Keywords: Papaya seed powder, a non-steroid aromatase inhibitor, masculinization.