Variability of the lysozyme content in bream from the Rybinsk Reservoir in different seasons of the annual cycle

Abstract

The seasonal variability of the lysozyme content has been detected in the liver, kidney, and spleen of bream. It is manifested in a higher lysozyme content in cold winter months and lower values in other seasons. It is shown that the enzyme activity is absent in blood serum of the studied fish regardless of its amount in immunocompetent organs. A high content of lysozyme in organs in the cold season of the year is not the result of the immunomodulatory effect of water temperature on this parameter but can be determined by physiological factors that do not depend on seasonal variations of the environmental temperature. It has been established that the blood serum in fish does not indicate the entire dynamics of the enzyme in the organism.