Giza.

In the present study Edwardsiella tarda isolated from local Clarias gariepinus was highly pathogenic and effective when experimentally inoculated in Oreochromis niloticus fish. So formalized inactivated bacterin, outer membrane protein and lipopolysaccharide (LPS) vaccines were prepared from this isolate and injected intraperitoneally (IP) in three groups of Clarias gariepinus fish. The quality control analysis proved that the prepared vaccines were free from any contaminant. The safety tests illustrated that the prepared vaccines did not show any abnormalities or adverse reactions among the injected fish during the observation days. Antibody titers to Edwardsiella tarda vaccines were estimated using microagglutination and ELISA methods. The agglutinating and ELISA antibody titers of fish vaccinated with outer membrane protein were 2560 and 2570 at 4 weeks post vaccination, respectively, followed by LPS ( 1280 and 2132) and formalin-inactivated vaccine ( 1040 and 1382), respectively. The laboratory challenge study showed that the protection rates of Outer membrane protein, formalin-inactivated and Lipopolysaccharide vaccines were 100%, 96 % and 92%, respectively. SDS-PAGE profiles analysis of the prepared vaccines illustrated that, the sonicated Edwardsiella tarda cells had 1