Use of hempseed meal, poultry by-product meal, and canola meal in practical diets without fish meal for sunshine bass (Morone chrysops x M. saxatilis)

In an effort to reduce fish meal (FM) use in diets for sunshine bass, a feeding trial was conducted. Four practical floating diets were formulated to contain 40% protein, similar energy levels, and without FM. A fifth diet was formulated to contain 30% FM and served as the control diet. Ten fish were stocked into each of 20 110-l aquaria and were fed twice daily (0730 and 1600 h) amounts of diet similar to that of the aquarium consuming the most diet at that feeding. Diets were formulated to contain as major protein sources: Diet 1, 35% soybean meal (SBM) and 35% meat-and-bone meal (MBM); Diet 2, 27% SBM + 27% MBM + 20% hempseed meal (HSM); Diet 3, 30% SBM and 30% poultry by-product meal (PBM); Diet 4, 27% SBM + 27% MBM + 20% canola meal (CM). The control diet (Diet 5) had 30% SBM and 30% FM. At the conclusion of the feeding trial, percentage weight gain of sunshine bass fed Diet 1 was significantly (P < 0.05) higher (299%) compared to fish fed Diet 3 (197%) and Diet 4 (226%), but not different from fish fed Diets 2 and 5. Specific growth rate (SGR) of fish fed Diet 1 was significantly higher (1.97%/day) compared to fish fed Diet 3 (1.52%/day), but not different compared to fish fed all other diets. Percentage survival and the amount of diet fed were not significantly different among all treatments and averaged 95% and 111 g diet/fish, respectively. Feed conversion ratios (FCRs) of fish fed Diets 3 and 4 were significantly higher (2.71 and 2.88, respectively) compared to fish fed the other diets. Percentage fillet weight and hepatosomatic index (HSI) were not significantly different among treatments and averaged 22.7% and 2.04%, respectively. Proximate compositions of fillets were not different among fish fed all diets and averaged 23.9%, 19.6%, and 2.0% for moisture, protein (wet weight basis), and lipid (wet weight basis), respectively. Results from the present study indicate that diets without FM can be fed to juvenile sunshine bass without adverse effects on growth, survival, and body composition. Further research needs to be conducted in ponds on the diet formulations used in the present study to verify results.