Lysozyme Content in Organs and Blood Serum in Various Species in the Volga River

The results of study of lysozyme content in kidney, liver, spleen, and blood serum of 12 fish species in the Volga River, which belong to six different orders, are presented. It has been established that the lysozyme level in the organs and blood serum is different in representatives of different taxons. The highest enzyme content was observed in sterlet (order Acipenseriformes), while the lowest content, in burbot (order Gadiformes). The enzyme content and its distribution in visceral organs depended on fish phylogeny, but not on the type of feeding (vegetarian or predatory) and the place of the constant habitation (fresh river or salted sea water). There were seasonal and yearly variations of the lysozyme concentration in fish organs and tissues. The many-year studies have established the regularity in enzyme distribution in sturgeon fish: kidney > spleen > liver > blood serum, this regularity being independent of the sturgeon species and constant during intra- and inter-year variations.