Evaluation of supplemental carbohydrase and protease in plant-based diets for hybrid striped bass (Morone saxatilis ♀ x M. chrysops ♂)

A 12-week digestibility trial and an 8-week growth trial were conducted to evaluate supplemental carbohydrase and protease additives in plant-based diets for hybrid striped bass (HSB). The additives were supplemented to soybean meal (SBM; S) or SBM/dried distiller's grains with solubles (SD)-based diets. In the digestibility trial, carbohydrase and protease were supplemented to S diets at 1X of manufacturer's recommended levels (MRL) and to SD diets at 1X and 2X MRL. The apparent digestibility coefficients (ADCs) of dietary dry matter, protein, and energy were unaffected by the supplemental enzymes, but the ADC of neutral detergent fiber increased from < 0.10 to 0.34 (1X MRL) and to 0.27 (2X MRL) in S and SD diets, respectively. No effects of supplemental carbohydrase were detected in the growth trial. While future studies should focus on assessing optimum levels of enzyme additives in feeds, our findings indicate that supplemental carbohydrase can increase fiber digestibility in HSB.