Digestive Enzyme Activities in Different Size Groups and Segments of the Digestive Tract in Labeo Rohita (Day, 1878)

Abstract

Variations in the activities of some digestive enzymes were studied in the different size groups of Indian major carp, Labeorohita. Regional distribution of digestive enzymes was also investigated from four intestinal segments of adult fish. The activities of amylase, trypsin, total protease and chymotrypsin increased along with increase in length and weight of the fish, having its highest value in the size group with 35.44 ± 3.2 cm and 549.67 ± 117.0 g compared to smaller and bigger fish. Hepatosomatic index and digestive somatic index declined with increase in fish size. Relative gut length showed an increasing trend up to size group with 26.22 ± 2.7 cm and 227.3 ± 44.5 g and thereafter stabilised. Activity of amylase was the highest (at both pH 4.5 and 7) in proximal intestine as compared to other segments. Cellulase activity was the highest in distal intestine and absent in hepatopancreas. The proximal intestine exhibited the highest activity for all the proteases, followed by anterior bulb and the rest of the segments; hepatopancreas recorded the least proteases activity.