Vaccination Trials in the Japanese Flounder against Edwardsiellosis

Abstract

The Japanese flounder (Paralichthys olivaceus) were vaccinated with formalin-killed cells (FKC) of Edwardsiella tarda by intramuscular injection, immersion and oral administration. Fish were also immunized by injection with diluted extracellular products (ECP) and intracellular components (ICC) of the bacterium, both of which were found lethal to flounder. As a result, mean serum agglutinating antibody titers against FKC rose in all the immunized fish groups except those vaccinated by immersion with FKC. When the immunized and control fish were challenged by injection and immersion with live cells, death was delayed in most of the immunized groups. However, clear protection was not observed in any group immunized either with FKC, ECP or ICC.