Protective systems of immunocompetent organs in fishes from different ecological and systematic groups

This article presents the results of analysis of parameters of the immune, antioxidant, and monooxygenase systems in the immunocompetent organs (pro- and mesonephros, spleen, and liver) of species belonging to different systematic and ecological groups, namely, northern pike Esox lucius, zander Sander lucioperca, and bream Abramis brama. Although having the same features in the functioning of homeostatic mechanisms in the species under study, significant differences were revealed between bream and another two species with respect to the parameters of the nonspecific immunity of tissues and enzyme systems that perform protective functions. In all the three species, the basic role in processes of immunopoesis and nonspecific protection is played by the kidneys and spleen, while the greatest values of the parameters of antioxidant defenses and ethoxyresorufin-O-deethylase activity were recorded in the liver.