Biological control of Flavobacterium psychrophilum infection in ayu (Plecoglossus altivelis altivelis) using a bacteriophage PFpW-3

Abstract

The efficacy of using a bacteriophage (phage) to control Flavobacterium psychrophilum (F. psychrophilum)infection of ayu (Plecoglossus altivelis altivelis) was evaluated in this study. Intramuscular challenge failed to inducesufficient infection levels; therefore, a newly designed net-scratch challenge method was also used to induce bacterialinfection. Administration of phage PFpW-3 in F. psychrophilum-infected ayu showed notable protective effects, increasedsurvival rates and mean times to death. Additionally, the fate of inoculated bacteria and phage in ayu were investigated. Our results suggest that the phage PFpW-3 could be considered an alternative biocontrol agent against F. psychrophiluminfections in ayu culture.