Effect of Ellagotanins and Probiotic “Ecoflor” on Sterlet Nonspecific Immunity Indices

Abstract

The experimental study of the effect of feed additive based on ellagotanins and immobilized probiotic “Ecoflor” on some parameters of non-specific immunity of sterlet Acipenser ruthenus was carried out. Feed additives based on ellagotannins are one of the numerous preparations of natural origin. They have antibacterial and immunostimulating properties. Biologically active additive “Ecoflor” is a consortium of live antagonistically active strains of bifido- and lactobacilli immobilized on enterosorbent. During the experiment, control and experimental groups were kept in flow-through plastic pools. Sterlets were fed 6 times a day. Drugs were added to the feed according to the instructions. Sampling was carried out before the start of the experiment, on 7, 14, 30, 45 and 60 days. Material for the study was taken from 5 individuals from each group. Peripheral blood was taken from the tail vein. After autopsy, tissue pieces of immunocompetent organs (kidney, spleen and liver) were taken from the fish into dry sterile tubes. Blood coagulation and clot retraction were waited for to obtain serum. The serum was then withdrawn with a syringe with a fine needle and transferred into an Eppendorf tube. For further studies, the homogenate was prepared from kidney, spleen and liver with physiological solution in the ratio of 1:6. The level of bacteriostatic activity, C-reactive protein and nonspecific immune complexes was determined in blood serum samples. In homogenates of kidney, spleen and liver the content of immune complexes was determined. The study established high indices of antimicrobial properties of blood serum in all studied fish and the absence of immunodeficient individuals. Lower indices of bacteriostatic activity in experimental groups and zero percent of immunodeficient individuals indicate insignificant influence of preparations on nonspecific antibacterial defense. The majority of the studied fish had a positive level of C-reactive protein, which indicates the presence of inflammatory processes in the body. The content of nonspecific immune complexes in the liver was several times higher than in other tissues, which may be due to the neutralization of components included in the preparations.