Immune response of rainbow trout (Oncorhynchus mykiss) to selected antigens of Yersinia ruckeri.

摘要

This study was conducted to determine the effects of Yersinia ruckeri antigens on the immune mechanisms of rainbow trout (Oncorhynchus mykiss). 120 fish, 20-30 g, were used in the study. After injecting 1 mg of formalin-inactivated whole cells (FKC) and O-antigen (Ag-O) intraperitoneally, blood was taken from the caudal vein of anaesthetized fish and metabolic activity of leukocytes (Nitroblue tetrazolium (NBT) activities), phagocytic activity (PA), phagocytic index (PI), serum protein and serum total immunoglobulin (TIg) levels were determined on day 30 after the first immunization. The same procedure was conducted in the control group. In all the experimental groups, considerable increases in the immune indicators were found and significant differences detected between the control and experimental groups (p<0.05). Metabolic activity of leukocytes decreased significantly (p<0.05) during the following treatment with antigens when compared with the control fish group. It is suggested that FKC and O-antigen directly activate the phagocytic activity. However, further studies should be performed on the specific and non-specific immune indicators of rainbow trout exposed to Yersinia ruckeri and other bacterial antigens.