A comparative histochemical survey of enzymes associated with the processes of digestion in Ostrea edulis and Crassostrea angulata (Mollusca: Bivalvia)


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    Zoology Department, University College, Galway, Eire.


No major differences in either concentration or location of enzymes were noted between the two species. An increase in enzyme production was noted in “fed” individuals–this being a direct response to the presence of food material. The gastric shield of both species was found to possess enzymic activity. The epithelium responsible for secretion of the crystalline style was also seen to secrete digestive enzymes which would be incorporated into the matrix of the style. Exopeptidases were identified in the walls of blood vessels and are attributed with the role of continued digestion of food material, prior to transport around the body. The mid-gut contains a number of enzymes in high concentrations and serves a digestive as well as an absorptive role. Lipid is seen to be an important storage product, especially in the connective tissue surrounding the digestive diverticula.