ABSTRACT
Bacteria capable to secrete enzymes hydrolyzing proteins and carbohydrates proved to be associated with the digestive-transport surfaces of the bream intestine and tegument of cestode Caryophyllaeus laticeps. Apparently, the contribution of symbiotic digestion to the hydrolysis of polymers increases during active feeding of fishes, while at low feeding rate, bacteria can compete with the host and its parasite for the available monomers. Secretion of bacterial enzymes hydrolyzing both complex carbohydrates and disaccharides reduces the metabolic expenditures of the macroorganisms for the synthesis of their own hydrolases. Glucose resulting from hydrolytic activity of bacterial enzymes can be used by all members of the established community. While bacteria colonizing the digestive-transport surfaces of the host and parasite were generally similar, some specific features were also observed probably due to the structural peculiarities of the intestinal mucosa and cestode tegument.
