Growth, Nutrient Deposition, Plasma Metabolites, and Innate Immunity Are Associated with Feeding Rate in Juvenile Starry Flounder ().

A 10-week feeding trial was conducted to evaluate the effects of different feeding rates on growth performance, nutrient deposition, plasma metabolite, and immunity of juvenile starry flounder. Fish (initial mean body weight, 183.6 ± 2.3 g) were subjected to eight feeding rates (0.4, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, and 3.2% body weight/day [BW/d]) with a commercial diet containing 53.5% crude protein and 10.2% crude lipid. After the feeding trial, fish growth increased significantly ( < 0.05) from 0.4% to 2.0% BW/d, with no significant differences being observed beyond 2.0% BW/d. Protein and lipid gains in the whole body and liver of the fish fed 2.0-3.2% BW/d were significantly ( < 0.05) higher than those of the fish fed 0.4% and 0.8% BW/d. Conversely, protein retention in the whole body and the liver decreased with an increased feeding rate. Lysozyme activity was significantly ( < 0.05) higher in the fish fed 1.6-2.8% BW/d than in those fed 0.4-1.2% BW/d. The best-fit model analyses for optimum feeding rate (OFR) revealed that the estimate for each parameter varied between 0.7% (feed conversion ratio) and 3.1% (lipid gain in carcass) BW/d. The OFR for productivity (weight gain) and enhanced innate immunity (lysozyme) were estimated at 2.4% and 1.7% BW/d, respectively.