VACCINATION TRIALS IN THE JAPANESE FLOUND ER AGAINST EDWARDSIELLOSIS

The Japanese flounder (Paralichthys olivaceus) were vaccinated with fo rmalin-killed cells (FKC) of Edwardsiella tarda by intramuscular injec tion, immersion and oral administration. Fish were also immunized by i njection with diluted extracellular products (ECP) and intracellular c omponents (ICC) of the bacterium, both of which were found lethal to f lounder. 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 challenge d by injection and immersion with live cells, death was delayed in mos t of the immunized groups. However, clear protection was not observed in any group immunized either with FKC, ECP or ICC.