Microflora in the alimentary tract of gray mullet, 4: Estimation of enzymic activities of the intestinal bacteria

Polyacrylamide gel electrophoresis was used to compare the enzymic activities of the bacteria in the intestine of gray mullet, Mugil cephalus , an amphidromous fish with an undeveloped stomach. These bacteria may help the digestion of high molecular weight compounds in the intestine. It was found that most of the isolates possessed strong proteolytic activity, in which the gelatioblytic activity was stronger than the caseinolytic activity. Almost all Vibrio and Enterobacter isolated from the intestine possessed strong protease and amylase isozymal electrophoretic bands. Clear differences between the protease and amylase isozyme zymograms were noticed with Vibrio, Enterobacter , and the other isolates. Some of the isolates possessed chitinase and lecithinase activities.