Abstract

The effect of replacing fish protein with soya protein in tilapia (Oreochromis niloticus) diets was examined. Three isoproteic (35%) diets containing 0% (FD); 50% (MD) and 100% (SD) fish protein substituted by soya protein were formulated. Fish (initial weight = 11.56 ± 4.22 g) was fed with experimental diets for 180 days. Results showed that the best growth was achieved with fish fed FD. Growth parameters such as final body weight, body weight gain and specific growth rate decreased with increased dietary soya protein. In contrast, no significant differences were found in feed and protein utilization parameters. For carcass trait, ash, crude fat, and energy varied significantly with soya protein incorporation in fish diet. Concerning organoleptic characteristics, odour and texture in mouth were not affected by incorporation of soya protein in diet. In contrast, texture, flavour, and general appreciate note were affected by dietary treatment. Partial substitution of fish protein by soya protein gave more pronounced sweet flavour.

Key words: Oreochromis niloticus, fish protein, soybean meal, growth, proximate composition, organoleptic characteristics.