THE IMMUNE-RESPONSE OF RAINBOW-TROUT (ONCORHYNCHUS-MYKISS) INJECTED WITH 5 RENIBACTERIUM-SALMONINARUM BACTERINS

Five bacterins consisting of formalin-killed, heat-killed, pH-lysed, S treptococcus bacterin (formalin-killed cells)-mixed, or ultraviolet (U V)-killed cells of Renibacterium salmoninarum were tested for the immu ne responses elicited in rainbow trout (Oncorhynchus mykiss). Low leve ls of agglutinating antibody titres were formed in vaccinated fish and in some fish these were undetectable. Phagocytosis was significantly increased in vaccinated fish, except with the Streptococcus-mixed bact erin, and the chemiluminescent responses of leucocytes were stimulated only with the pH-lysed and UV-killed bacterins. However, no significa nt protection was observed in the fish when they were experimentally c hallenged.