Development of some digestive enzymes in Eurasian perch larvae Perca fluviatilis

The activities of some digestive enzymes were investigated in Eurasian perch Perca fluviatilis larvae fed live preys during the first month of life. Activities of pancreatic and intestinal enzymes displayed a pattern characteristic of developing animals. Pancreatic enzymes were efficient at the time of hatching. Trypsin and amylase specific activities increased during the first developmental days, then decreased even though segmental activities increased continuously as the larvae grew. The increase of chymotrypsin specific activity was proportional to fish growth. From day 21 after hatching to the end of experiment, the strong increase in the activities of alkaline phosphatase, leucine-aminopeptidase N, maltase and gamma-glutamyl transpeptidase reflected the development of brush border membranes of enterocytes. This phenomenon occurred concurrently with a decrease in a cytosolic enzyme, the leucine-alanine peptidase. These opposite patterns indicate a maturation of enterocytes and the acquisition of an adult mode of digestion within the first month of live.