DAO 55:261-264 (2003)  -  doi:10.3354/dao055261

Efficacy of oral vaccine against bacterial coldwater disease in ayu Plecoglossus altivelis

Motoki Kondo1, Kenji Kawai1, Masaya Okabe2, Nobuyasu Nakano3, Syun-ichirou Oshima1,*

1Fish Disease Laboratory, Department of Aquaculture, Kochi University, Nankoku, Kochi 783-8502, Japan
2Kochi Prefectural Freshwater Fisheries Center, Tosayamada, Kochi 782-0000, Japan
3Kochi Freshwater Fisheries Association, Yoshikawa, Kochi 781-5214, Japan
*Corresponding author. Email:

ABSTRACT: The development of a practical vaccination method against bacterial coldwater disease (BCWD) in ayu Plecoglossus altivelis and the efficacy of oral administration of formalin-killed cells (FKCs) of Flavobacterium psychrophilum was investigated. The FKC was administrated at a dose of 0.1-0.2 g kg-1 body weight to juvenile ayu (0.5 g body weight) every day for 2 wk or on 5 days over 2 wk. Experimental immersion challenge at 3 and 7 wk after vaccination showed significantly higher survival rates than the controls. The results show the effectiveness of oral vaccination against BCWD in ayu.

KEY WORDS: Oral vaccine · Immunization · Ayu · Flavobacterium psychrophilum · Bacterial coldwater disease · BCWD

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