Improved digestibility of plant ingredient-based diets for European seabass (Dicentrarchus labrax) with exogenous enzyme supplementation

This study evaluated the effect of supplementation of a plant ingredients-based diet with two levels of commercially digestive enzyme products: Synergen™ and Natugrain® on the apparent digestibility coefficients (ADCs) of nutrients and on digestive enzyme activities in European seabass (Dicentrarchus labrax) juveniles. A control diet was formulated with 450 g/kg CP (200 g/kg from fish meal + 800 g/kg from plant protein) and 180 g/kg CL (fish oil), and four other diets were made similar to the control but supplemented with 0.2 g/kg or 0.4 g/kg of Synergen™ and Natugrain®. Digestive enzyme activities were not affected by dietary treatments. Nevertheless, chyme pH along the intestine of fish fed the Natugrain®-supplemented diets was reduced. The ADC of nutrients increased with exogenous digestive enzyme supplementation, with the highest ADC values being observed for the 0.4 g/kg Natugrain® diet. The ADC of dry matter, protein, lipids, energy and phosphorus in this diet were 26%, 6%, 4%, 16% and 63% higher, respectively, than in the control diet. Overall, diet supplementation with exogenous enzyme complexes seems to have high potential for improving the utilization of plant feedstuff-rich diets for seabass juveniles. This study revealed that Natugrain® was more effective than Synergen™ in improving the ADC of nutrients and energy in European seabass juveniles.