FATE OF 4 FISH PATHOGENS AFTER EXPOSURE TO FISH SILAGE CONTAINING FISH FARM MORTALITIES AND CONDITIONS FOR THE INACTIVATION OF INFECTIOUS PANCREATIC NECROSIS VIRUS

Exposing three bacterial fish pathogens (Aeromonas salmonicida, Yersin ia ruckeri and Renibacterium salmoninarum) to a commercial fish silage caused their rapid destruction. However, it was found that infectious pancreatic necrosis virus survived in silage for long periods at the prevailing ambient temperature in Scotland. Native levels of virus cou ld be inactivated by heating the silage preparation to a temperature o f 60-degrees-C for 2 h or by the addition of the virucidal agent Virko n to 1/100 w/v dilution. As Divosan Forte only inactivated IPN virus s lowly in silage acids, Virkon would be the better terminal disinfectan t for silage. The practice of ensiling fish farm wastes to hygienicall y dispose of infected materials such as mortalities and infected offal s is discussed.