넙치(Paralichthys olivaceus)에서 Edwardsiella piscicida의 자연감염과 인위감염 특성에 관한 연구

Abstract

The purpose of this study is to find out the difference in the characteristics of natural and artificial infections of Edwardsiella piscicida in olive flounder (Paralichthys olivaceus). Natural infected group were collected from olive flounder aquaculture farm, and artificial infected group were tested for 14 days after Intraperitoneal (IP) injection to histopathological and blood chemical analysis. As a result, symptoms of exophthalmos in the natural infection group and peritonitis and intestinal congestion in the artificial infection group were specifically observed. Especially, histopathological results showed that hepatic abscesses were frequently generated from the inside of hepatocytes in the natural infection group, while peritonitis was preceded in the artificial infection group, necrosis of hepatocytes was lesser than in the natural infection group. These results are due to the outflow of blood components from peritoneal or barrier blood vessels to prevent sepsis in which bacteria that penetrated into the abdominal cavity spread throughout the body during abdominal vaccination, resulting in an immune response. Blood chemical results show that AST, ALT, and BUN values increased with the degree of infection, and that the BUN levels representing kidney function increased with the degree of infection, which is considered to have worsened kidney function due to damage to real tissue in the kidney. Therefore, it was confirmed that IP injection of E. piscicida against olive flounder showed a insignificant effect of sepsis compared to natural infection, showing lesser pathogenicity in artificial infected fish.