Sanz A*,Furné M,Hidalgo MC,Domezain A,García-Gallego M
This work provides a comparative study between sturgeon (Acipenser naccarii) and trout (Oncorhynchus mykiss) on the utilization of diets in which protein is partially replaced by carbohydrates and/or lipids, examining the fish growth and the possible adaptive response of the digestive enzymes. Positive relationship between amylase secretion and carbohydrate level in the diet for trout and between lipase secretion and lipid level in the diet in sturgeon were found. In this study we proved, once more, that sturgeon show a more favourable performance than trout when fed on diets with lower protein/energy ratios. This difference enables sturgeon to be fed diets with a lower protein content (approximately 10% lower) than that of the diets used to feed strictly carnivorous fish. The reduction of the dietary protein level could mean both a lower feed cost, and a lower nitrogenous wastage to the environment.