Field Trials of a Vaccine with Water-soluble Adjuvant for Bacterial Coldwater Disease in Ayu Plecoglossus altivelis

Abstract

The efficacy of a vaccine with watersoluble adjuvant (Montanidae IMS 1312) for bacterial coldwater disease was examined in ayuPlecoglossus altivelisunder field conditions. Ayu injected intraperitoneally with formalin-killed bacterin ofFlavobacterium psychrophilummixed with the water-soluble adjuvant were reared in concrete ponds with river water from April to September in 2000 and 2001. Cold water disease occurred spontaneously from the middle of May to the middle of June (2000) and to the middle of July (2001). The mortalities of twice-vaccinated ayu were significantly lower than non-vaccinated ayu in both years and relative percent survivals (RPS) were 33.0% in 2000 and 39.6% in 2001.