Determination of optimal feeding rates for juvenile lake sturgeon ( Acipenser fulvescens) fed a formulated dry diet

Two 3-week growth trials were performed to determine the optimum feeding rate of juvenile lake sturgeon (Acipenser fulvescens) fed with a semi-purified dry diet (protein, 440 g; lipid, 130 g/kg) at different feeding rates: 5, 10, 20, 30, and 40 g/kg body weight per day (BW/.d-1), for 36 g-sized fish; and 2.5, 5, 10, 20, and 30 g/kg BW/.d-1, for 80 g sized fish. Feeding rates significantly influenced growth performances, feed conversion ratio, wholebody lipid and moisture contents, energy and protein retention, and fasted blood glucose levels (p < 0.05). The ratio of total C/total N measured in whole fish was positively correlated to the feeding rates and the lipid contents of whole fish. Suboptimal feeding significantly depressed growth performance and protein synthesis based on the measurement of RNA/DNA ratio in white muscle. Based on polynomial regression models, an optimal feeding rate to support the maximum growth, protein and energy retention was 34.5, 22 and 27.3 g/kg BW/.d-1, respectively, for fish sized at 36-72 g; and 29.0, 16.9 and 19.9 g/kg BW/.d-1, respectively for fish sized at 80-140 g. Results of this study will benefit future research to develop practical feeds to replace frozen live feed and feed management for lake sturgeon.