The Flukeworm Azygia lucii and the Pike Esox lucius: Features of Their Relationship

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