The present work aimed to investigate the effect of incorporation of increasing levels of Biogen in tilapia diets on growth performance and feed utilization of Nile tilapia (Oreochromis niloticus).The experimental diets were formulated and Biogen was incorporated in five different doses, 0, 0.1, 0.2, 0.3 and 0.4% for the diets D1, D2, D3, D4 and D5, respectively and tested in 15 glass aquaria (3 replicates for each treatment). The experimental period lasted after 90 days. At the end of this experiment (90 days) the highest average body weight (BW) was recorded for fish group fed the diet D2 followed in descending order by those in groups D4, D2, D5 and control group D1 with significant differences between the different diets and the same trend was also observed for body length (BL), weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER). Feed intake during the entire period found to be 28.15, 32.30, 26.33, 27.49 and 26.93 g for the diet enriched by, 0, 1, 2, 3, and 5 g Biogen/kg diet, respectively and the differences between the FI values were significant (P