The study aimed to investigate the effect of replacing soybean meal (SBM)protein by treated Jojoba seed meal (JSM) in diets of Nile tilapia (Oreochromis niloticus) on growth performance, nutrient utilization, carcass traits, body chemical composition and digestibility of nutrients of Nile tilapia,reared under semi-intensive conditions in fiber glass tanks. The experimental tanks (1m x 2m x 0.5m) each contains one m3 water volume, were used in this study. The three tanks represented three dietary treatments, the first tank served as a control, where the experimental fish were fed on the control diet containing soybean meal (SBM) as a source of plant protein with fish meal as a source of animal protein. Fish of the second and third tanks were fed on diets containing the Jojoba seed meal (JSM) to replace 25 and 50% of SBM protein, respectively. The experimental tanks were stocked with Nile tilapia fingerlings at a density of
50 individuals in each tank. The experimental period lasted 18 weeks after start. The initial weight of the experimental fish ranged between 7.20 ± 0.09 g and 7.5 ± 0.08 g and they were allotted randomly into the experimental tanks. The
experimental rations contained 30% crude protein and 4500 kcal gross energy/kg diet and the experimental diets were formulated to be almost isonitrogenous isocaloric. The experimental diets were fed at a rate of 3% of tank fish biomass 6 days a week, in two portions, at 9:00 a.m. and 3:00 p.m.The results of this study revealed that, the highest (P<0.05) final weights, specific growth rate, protein and nutrient utilization were recorded by JSM 25% group followed by the control group and the JSM 50% groups, respectively. The same trend was observed in apparent digestibility coefficients.
Therefore, these results suggest that up to 25% of soybean meal can be replaced by treaded Jojoba seed meal protein in Nile tilapia diets without any adverse effect on growth performance, feed and protein utilization, body composition
and digestibility of nutrients.