Effect of dietary lipid level on juvenile black sea bassCentropristis striatafed two protein sources

Abstract

A 10-week feeding trial was conducted with juvenile black sea bass Centropristis striata fed isonitrogenous diets (46% CP) with four lipid levels (7, 10, 13 and 16%) to identify dietary lipid levels supporting maximum weight gain and efficiency. Menhaden fish meal (FM) and animal protein concentrate (APC) were used in a 2×4 factorial experiment to evaluate effects of protein quality and lipid level on production. Weight gain, thermal growth coefficient, protein and energy retention, proximate composition and hepatic indices were evaluated. Weight gain was higher (P<0.05) in FM treatments and no protein sparing effect was observed. All growth, efficiency and retention parameters, except apparent net protein utilization (ANPU) among FM diets, were independent of dietary lipid. Based on proximate composition, diets should be restricted to no more than 13% lipid in 46% CP diet, and can be reduced to 7% without loss of growth and efficiency. Second order polynomial regressions on ANPU indicated 10–12% dietary lipid in a 46% CP diet is appropriate depending on protein quality. Reducing dietary lipid in current commercial feeds fed to black sea bass could represent a substantial cost savings in feed production.