Biological Control of Fish Viral Diseases by Anti-Viral Substance Producing Bacteria

Abstract

Many bacteria producing anti-viral substances were isolated from the aquatic environment. Fish intestinal bacteria such as Aeromonas spp. And Vibrio spp. Producing anti-viral substances were isolated from intestinal contents of masu salmon (Oncorhynchus masou), Japanese flounder (Paralichthys olivaceus) and barfin flounder (Verasper moseri). These Aeromonas strains produced anti-infectious hematopoietic necrosis virus (IHNV) substances and Vibrio strains showed anti-IHNV, Oncorhynchus masou virus (OMV) and barfin flounder nervous necrosis virus (BF-NNV) activities. ′ When Aeromonas spp. Strains M-26 and M-38 were mixed with food pellets and fed to rainbow trout (O. Mykiss) and masu salmon, both bacteria became dominant in the intestinal microflora and anti-IHNV activity was observed in homogenates of intestinal contents. These rainbow trout and masu salmon fed the Aeromonas spp. Showed more resistance to the artificial IHNV challenge test. Barfin flounder fed Vibrio sp. Strain 2IF6a with a Item ia salina showed the anti-OMV and BF-NNV activities in the intestinal contents. Larvae fed the Vibrio sp. Showed a higher survival rate than the fish cultured using the virus free sea water. © 1999, Japanese Society of Microbial Ecology & The Japanese Society of Soil Microbiology. All rights reserved.