Effects of Tribulus terrestris extract and 17 α-methyl testosterone on masculinization, growth, economic efficiency and health assessment of Nile tilapia (Oreochromis niloticus)

Monosex (male) Nile tilapia had three times better growth than the female. The excessive and unobservable use of hormones for fish production and sex reversal negatively affects fish production, profitability, fish, and human health but the optimum MT and TTE intake has a favorable impact on fish growth, health and profitability. Fish sex reversal has been significantly affected by phytochemicals, which are currently being investigated as a natural alternative agent. Thus, this study aimed to investigate the effects of dietary inclusion of Tribulus terrestris extracts (TTE) and 17 alpha-methyl testosterone on sex reversal, growth performance, survivability, and adaptability for Nile tilapia. A 66-day trial was conducted with four formulated diets: T1 (40 mg/kg of 17 alpha-MT + TTE), T2 (50 mg/kg of 17 alpha-MT + TTE), T3 (60 mg/kg of 17 alpha-MT + TTE) and a control diet (T4). The fish were fed 36% dietary protein and daily ration of feed ranged from 10 to 14% of their body weight and feeding frequency up to eight times a day. Eight hundred healthy seeds (0.02 +/- 0.01 g initial weight) were randomly distributed (2000 fish/tank) in four concrete tanks (548 cm x 213 cm x 100 cm) each; length x width x depth). The maximum weight gain (WG), final body length (FBL), final body weight (FBW), average daily weight gain (ADWG), survival rate (SR), specific growth rate (SGR), sex reversal, profitability and lower feed conversion ratio (FCR) of Nile tilapia were recorded in T2, significantly varied compared to the other treatments (p < 0.05). The highest percentage (100%) of tilapia males was observed in T2, which was significantly different from other treatments (p < 0.05). T2 (50 mg kg(-1) of 17 alpha-MT + TTE) showed the highest growth in Nile tilapia and had a major impact on fish health, blood, and morphological indices. The phenomenal regression also indicated that the T2 dose is optimum for 100% Oreochromis niloticus mono-sex seed production.