Production of Monosex All-Male Nile Tilapia Using Ethanol Extract of Tribulus terrestris Seeds

Mixed sex juveniles of Nile tilapia (mean weight 0.025 ± 0.009 g; mean length 1.25 ± 0.012 cm) were subjected to dietary treatment (commercial fish feed, Tokyu, Japan, 30% crude protein) with ethanolic extract of Tribulus terrestris seeds at different concentrations (0.0, 2.0, 2.5, 3.0 g/kg feed) to evaluate the efficacy of the plant seed extract for induction of masculinisation in fish. Treatment with plant extract at different concentrations have resulted in significantly higher (P < 0.05) survival percentage compared to control indicating no adverse health effect of the plant extract. Fish fed diets containing the plant extract showed significantly higher (P < 0.05) percentage of males compared to fish fed control diet. Dietary supplementation with the plant extract at the concentration of 2.0 g/kg feed showed the highest percentage (91.53 ± 0.38) of males and may be considered to be the best concentration among the selected concentrations for monosex tilapia production with T. terrestris seeds extract. The result of the study indicates that ethanolic extract of T. terrestris seeds may have potential for inducing sex reversal in fish and this biodegradable natural plant material may be used for monosex tilapia production instead of synthetic steroids.