Growth, Survival, and Body Composition of Largemouth Bass Fed Various Commercial Diets and Protein Concentrations

Aquaculturists often intensively culture fish species before the nutrient requirements of the species are known. Largemouth bass Micropterus salmoides have been cultured on pelleted diets since the 1960s, but growth and survival of fish on these diets have not been evaluated. We examined growth rate, survival, and body composition of largemouth bass (initial total length, 110 mm) fed six commercial diets for 56 d. Largemouth bass fed diets for coolwater (W-16) and coldwater (Biodiet Grower) species grew faster than those fed diets formulated for bass (Black Magic Bass Food and Biosponge Bass Grower). Whole body protein, lipid, moisture, and ash were affected by the type of commercial diet. Lipid levels were higher for fish fed Biodiet Grower than for fish fed all other diets. Based on this evaluation, we recommend either W-16 or Biodiet Grower for rearing largemouth bass. Because protein is one of the most important components affecting performance of pelleted diets, we conducted a second set of experiments over a 51-d period to evaluate growth rate, survival, and body composition of largemouth bass (initial total length, 98 mm) fed four diets that ranged in protein concentration from 31 to 40%. Growth rate varied with protein level, and fish fed the two diets highest in protein grew faster than those fed the two diets lowest in protein. Lipid and moisture, but not protein and ash, were affected by diet type. Lipid content decreased and moisture content increased as dietary protein increased. Specific growth rate was greatest at a protein level of 37%, which was judged to be the optimum dietary level for these sizes of largemouth bass when the dietary energy level is 3.27 kcal/g.