A Comparative Analysis of the Effect of Intestinal Cestodes in Different Fish Species on Proteolytic Enzyme Activity

We found that all the six cestode species, Proteocephalus torulosus (Batsch, 1786), P. sagittus (Grimm, 1872), P. cernuae (Gmelin, 1790), Eubothrium rugosum (Batsch, 1786), Triaenophorus nodulosus (Pallas, 1781), and Caryophyllaeus laticeps (Pallas, 1781), which parasitize in the intestines of fish, such as the dace Leuciscus leuciscus L., stone loach Barbatula barbatula L., ruffe Gymnocephalus cernuus L., zope Ballerus ballerus L., burbot Lota lota L., pike Esox lucius Linnaeus, and bream Abramis brama L., alter the activity of proteolytic enzymes in the host intestinal mucosa. The infestation reduced the proteolytic activity level in some host species or enhanced it in the others. Whatever the direction of these changes, all the studied tapeworms were able to inhibit mucosal protease activity (as well as that of commercial trypsin). In some cestode species, the inhibitory effect was comparable to that of the synthetic serine protease inhibitor PMSF.