銅処理によるウナギのEdwardsiella tarda及びPseudomonas anguillisepticaに対する感受性の増大

抄録

The 24, 48, 96h and 14 d-TLm (median tolerance limit) values of copper to Japanese eel Anguilla japonica in extremely soft water at 25C°C were 750, 550, 510 and 340 μg-Cu/ι, respectively. Japanese eels were exposed to sublethal concentrations of copper (100 and 250 μg-Cu/ι)and challenged with Edwardsiella tarda, Pseudomonas anguilliseptica and Vibrio anguillarum. Copper exposure resulted in an increase in the susceptibility of eels to E. tarda and P. anguilliseptica, but not to V. anguillarum. When the eels were exposed to copper for 24 or 48 h, the effect was manifested most strongly, but reduced in the eels exposed for 96h. From the fact that corticosteroids admministration also enhanced the susceptibility of eels to the pathogens, it was deduced that increased susceptibility was a result of stress response to copper.