The role of proteases of food objects and enteral microbiota in nutritive and thermal adaptations of the digestive system in fishes

Abstract

The review presents the data on the activity and some thermal characteristics of proteases in the potential food objects of fishes and some enteral microbiota representatives that provide an induced autolysis and symbiotic digestion. It is shown that during the active feeding period the total protease activity in the prey tissues exceeds that in the fish gastric mucosa by 5–10 times. At low temperature, the relative activity of the prey tissue lysosomal hydrolases (20–35%) and enteral microbiota enzymes (up to 45%) may exceed that of proteases synthesized by the hepatopancreas and acting in the consumers’ intestinal mucosa (less than 10% of maximal activity). The data presented indicate the important role of proteases of food objects and enteral microbiota in nutritive adaptations of the fish digestive system.