Fish meal replacement by soybean products in aquaculture feeds for white snook, Centropomus viridis: Effect on growth, diet digestibility, and digestive capacity

Abstract

A feeding trial was conducted to evaluate the effect of the partial replacement of fish meal (FM) by either soybean meal (SBM) or soybean protein concentrate (SPC) on growth, feed utilization, apparent digestibility (AD), and digestive capacity in the white snook, Centropomus viridis. Seven experimental diets were formulated by replacing 0, 15, 30, or 45% of FM protein with either SBM or SPC; the control diet contained FM as the primary protein source. Juvenile fish (3.35 ± 0.24 g average initial body weight) were fed the experimental diets (n = 45 per diet) twice a day for 109 days. Fish fed the SBM-30 diet showed the highest weight gain, while those fed the SPC-45 diet showed lower body weight compared to the control group. Fish fed the SBM diets showed higher protein efficiency ratio and lower feed conversion ratio (FCR) than fish fed the SPC diets. Body fat content of fish fed the SBM or SPC diets was higher than the control group. Moreover, a reduction in pepsin activity in SPC-15 group, as well as a decrease in intestinal α-amylase activity and total alkaline proteases of pyloric caeca from SBM-30 and SPC-45 groups compared to control diet was observed. These results confirm those obtained in the AD assay, where apparent digestibility coefficients (ADC) in the experimental groups were higher than in the control group. Our results indicate that a 15–45% replacement of FM by SBM can be made in aquafeeds for juvenile C. viridis without affecting its growth, digestibility, or digestive capacity.