The effect of substituting fish meal with soybean meal on growth, feed efficiency, body composition and blood chemistry in juvenile spotted rose snapper Lutjanus guttatus (Steindachner, 1869)

Abstract

The purpose of this study was to evaluate the replacement of fish meal (FM) with soybean meal (SBM) in diets for juvenile spotted rose snapper with the overall goal of identifying practical diet formulations for commercial production of the spotted rose snapper. The response of spotted rose snapper to diets contained graded levels of FM was evaluated by measuring weight gain, feed efficiency, body composition and blood chemistry during a 12-week period. Four diets were formulated (43.7% crude protein, 14% crude lipid and 19.6kJg−1 gross energy) with 0, 20, 40 or 60% SMB protein replacing FM in diets. Diets were fed to juvenile spotted rose snapper (mean initial weight 17.75±0.03g) for 12weeks, and weight gain, feed efficiency, body composition and blood chemistry were assessed at the end of the feeding trial. Compared to the FM diet, there were no significant differences in weight gain, individual feed intake, specific growth rate or protein efficiency ratio (PER) of fish when 20% of the FM was replaced compared to fish fed the FM control diet. However, fish performance was reduced at higher levels of FM replacement, significantly so at the 60% replacement level. Hematological parameters were similar among the treatments. Fish fed the 60% SBM diet had significantly lower lipid levels than fish fed the other diets. There was no significant difference in survival of fish fed the different diets. A second order polynomial regression revealed maximum growth of the spotted rose snapper fed up to 19.4% SBM inclusion. The results of this study show that SBM is an acceptable ingredient to supply 20% of protein in spotted rose snapper diets, but that higher dietary levels reduce fish performance.