Evaluation of Different Sex Reversal Treatments in Red Tilapia Hybrid

Abstract

Effects of dietary inclusion of Tribulus terrestris and 17 α-methyltestosterone on sex reversal, growth performance, feed utilization, and survival rates of red tilapia were evaluated in this study. Red tilapia fry with an average weight of 0.02 ±0.003 g and an average length of 0.6 ±0.012 cm were subjected to six different sex reversal treatments. The experiment lasted for 112 days. Two T. terrestris extract treatments (1and 2 g/kg diet); three hormonal treatments with 17 α-methyltestosterone ( 30,60 and 100 mg/kg diet), were applied in this experiment plus a control group. The results of this study revealed that all plant and hormonal treatment showed significantly higher male percentages (p≤0.05) than the control. The highest male percentage of (90%) was achieved at the dose of 60 mg 17 α-methyltestosterone/kg followed by T. terrestris extract at 2 g/kg with a male percentage of (84.4%). Growth performance and feed utilization of red tilapia were better in the two treatments of T.terrestris extract, followed by the hormonal dose 60 mg/kg diet, than other treatments. A significantly higher survival rate of 85.44%, 83.33%, and 83.11% was achieved at 1 and 2 g T. terrestris extract/kg and the control respectively. The lowest survival (71.56%) was observed at the 100 mg 17 α -MT/ kg diet (p ≤ .05). Testes weight was significantly higher at 2 g T. terrestris extract/kg diet treatment compared with the other treatments and the control. The highest male gonado-somatic index records were found at the control and 2 g T. terrestris extract/ kg diet treatments. Conclusively, the addition of T. terrestris extract and 17 α –MT into red tilapia hybrid fry diets contributes in producing almost all-male tilapia population and enhancing growth performance and feed utilization of the fish.