EFFECT OF FEEDING RATE AND FREQUENCYON GROWTH PERFORMANCE, SEX CONVERSION RATIO AND PROFITABILITY OF NILE TILAPIA (OREOCHROMIS NILOTICUS) FRY IN HAPA AT COMMERCIAL HATCHERIES

This trial was conducted for twenty one days to evaluate the efficacy of feeding rate and frequency on growth performance, sex conversion ratio and profitability of monosex tilapia (Oreochromis niloticus) fry followed by a 45 days feeding trial to determine sex conversion ratio. A total of 360000 fry of three days- old (weight 10.99±0.01mg in average) were stocked in twelve hapa (2×4×1 m) at the rate of 30000 fry/hapa. The hapas were divided into six treatments on the basis of feeding rates and frequencies viz. changeable rates 30>20>10 and 4 times/day (T1), rate 30>20>10 and 6 times/day (T2), constant rate 20% for 4 times/day (T3), rate 20% for 6 times/day (T4), rate 15% for 4 times/day (T5) and rate 15% for 6 times/day (T6) having two replications. Fry were fed mixed feed with 17α-methyltestosterone (MT) hormone at a rate of 100 mg/kg diet and supplemented with mixture of vitamin C and selenium. The water quality parameters were within suitable ranges for proper growth of O. niloticus. After ending the trial period, significant variations (P≤0.05) were observed in six treatments and T2 showed the best performance in case of all parameters studied such as final weight, weight gain, feed conversion ratio, specific growth rate, sex conversion ratio and profitability. The lowest values were obtained with T5 (feeding rate 15% and 4 times/day).