Faculty of Fisheries, Nagasaki University, Nagasaki, Nagasaki 852-8521, Japan
Cu, Zn-superoxide dismutase (Cu, Zn-SOD) activities were compared in Japanese flounder Paralichthys olivaceus for four different kinds of bacterial infections. A significant increase in Cu, Zn-SOD levels was recorded in hepato-pancreas (approximately 6-fold activity of control fish) at the initial stages of Edwardsiella tarda infection, which decreased progressively to normal levels in the following 2 days. On the other hand, in fish infected with Vibrio anguillarum and Streptococcus iniae, activity of Cu, Zn-SOD was almost the same level as that in the control fish. Therefore, it was suggested that the remarkable change of Cu, Zn-SOD activities was a characteristic phenomenon of E. tarda infection.