Fluke worm Azygia lucii and pike Esox lucius: features of the relationship

The effect of Azygia lucii fluke infection on the activity of proteolytic enzymes functioning in the stomach of the host pike and the ability of worms to suppress this activity was studied. The activity of a wide range of proteases was detected in the pike’s stomach. In extracts of marita A. lucii, both pepsin-like activity and activity of alkaline proteases, a significant part of which are metal-dependent proteases, were determined. Even with a low intensity of invasion, trematodes cause an increase in the activity of pepsinlike proteases in the host’s stomach. Worm extract suppresses the activity of commercial pepsin, but neither the incubation medium nor the trematode extract have a statistically significant inhibitory effect on the activity of pepsin-like proteases of the gastric mucosa of pike.