STUDIES ON THE DIGESTIVE ENZYMES OF GRASS CARP, CTENOPHARYNGODON-IDELLA (VAL)

Three groups of grass carp fingerlings and one batch of adult fish were fed with different artificial and natural diets. To destroy the digestive tract microflora, which may have digestive functions, an antibiotic was used in the diets of one group of carp fingerlings. The activities of cellulase, amylase, protease and lipase were determined during postmortem examination. The pattern of distribution and activity of the digestive enzymes were found to depend on the type of diet ingested by the fish. Both endogenous and bacterial cellulase were found in grass carp. The presence of cellulase activity suggests the necessity for providing cellulose as an ingredient in the diet of grass carp. The presence of high amylase and protease activity in fish from the culture pond suggests that incorporation of animal protein, e.g. fish meal, is necessary for the preparation of a diet which would suit the enzyme pattern of the grass carp. Similar to previous research on this species, lipase activity was recorded to be the highest in the hepatopancreas.