Digestive enzymes of meagre (Argyrosomus regius) and white seabream (Diplodus sargus). Effects of dietary brewer's spent yeast supplementation

• Digestive physiology of two new species for aquaculture was assessed.
• Potential of brewer's spent yeast as a probiotic was evaluated.
• Digestive enzymatic profile of two species mirrors its feeding habits.
• Brewer's spent yeast supplementation increases fish digestive function.

Characterization of the major classes of digestive enzymes (amylase, protease and lipase) in the pyloric caeca and intestine of an omnivorous, white seabream (Diplodus sargus) and a carnivorous, meagre (Argyrosomus regius) fish species was assessed in response to dietary brewer's spent yeast (BSY, Saccharomyces pastorianus) supplementation. For that purpose, three isonitrogenous (50%) and isolipidic (12%) diets were formulated: unsupplemented (control) or supplemented with BSY at 1 or 2%. White seabream exhibited lower proteolytic but higher amylase and lipase activities than meagre. In white seabream, BSY administration enhanced amylase and protease activities in the pyloric caeca and the intestine and lipase activity in the pyloric caeca, while in meagre, improvement on amylase activity in the pyloric caeca was observed with the 2% BSY diet. The results of the current study indicate that white seabream has higher ability to digest non-protein energy sources than meagre and that diet supplementation with BSY improved digestive capacities in both species.