A two month feeding trial was conducted with Sobaity seabream juvenile (4.7 g) to determine the effect of soy protein in diet on growth and digestive enzyme activities. Fish were fed isonitrogenous (50%) and isoenergetic formulated (23 MJ/Kg) diets in which dietary protein was supplied by Kilka fish meal as control (0%) and a mixture of soybean meal, isolated soy protein and the fish meal by progressively increasing soy product inclusion in which 15%, 30%, 45%, 60% and 75% of fish meal protein was replaced in a way that marine protein dependency (MPDR) decreased significantly (p<0.05) in all treatments. The enzyme activities significantly decreased in all parts of the intestine with increasing dietary soy protein level this is probably due to the smaller digestibility coefficient of diets containing more level of soy protein.

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