Effect of three natural phytochemicals supplementation on growth performance, testosterone level and feed utilization of Nile tilapia ( Oreochromis niloticus )

An 84‐day feeding experiment was conducted to determine the effects of dietary ginseng extract ( GE ), tribulus extract ( TE ) and date palm pollen grains ( DPPG ) on growth, testosterone level and nutrient utilization of Nile tilapia, Oreochromis niloticus , fingerlings. Seven experimental treatments were conducted in three replicates: control fed basal diets without any supplementations, GE 0.2 (supplemented with 0.2 g  GE /kg diet), GE 0.4 (supplemented with 0.4 g GE /kg diet), TE 0.6 (supplemented with 0.6 g TE /kg diet), TE 1.2 (supplemented with 1.2 g TE /kg diet), DPPG 3 (supplemented with 3 g DPPG /kg diet) and DPPG 6 (supplemented with 6 g DPPG /kg diet). The results indicated that all dietary phytochemicals significantly increased growth compared to the control. Plasma testosterone levels were improved by 86.27%, 64.58%, 57.35% and 24.58% with TE 1.2 , GE 0.4 , TE 0.6 and DPPG 6 , respectively, more than the control. The relationship between testosterone and final body weight showed a significant simple linear regression with a positive correlation. The nutrient utilization imprxoved with higher doses of phytochemical supplementations. Moreover, protein content increased and ether extract decreased with phytochemical supplementation. The present results concluded that higher doses of GE , TE and DPPG could be used as growth promoters and testosterone boosters for Nile tilapia fingerlings.