The suppression in overall growth performance in fish fed diet four, where fish meal was replaced with soybean meal without phytase supplementation, might be attributed to the presence of antinutritional factor in soybean meal (
Linener, 1994; Vaintraub and Bulmaga, 1991) and an adverse effect of phytate on growth performance and bioavailability of various dietary components (Satoh et al., 1989; Richardson et al., 1985).