ABSTRACT: Japanese pearl oysters (akoya oyster: Pinctada fucata martensii) are currently suffering mass mortalities from akoya-virus infection. In the present study, akoya oysters were injected with an anti-viral, recombinant feline interferon-w (rFeIFN-w) in an attempt to confer resistance to this virus. In infectivity experiments, oysters were twice injected with rFeIFN-w at 1 mega unit kg^-1 of the meat weight. They were challenged with a single inoculation of cultured akoya-virus and held for 20 to 30 d at 25°C. Control oysters received only the viral challenge without rFeIFN-w administration. In prophylactic experiments, oysters that were given the akoya-virus on Days 1 to 5 after rFeIFN-w administration showed lower mortalities. Furthermore, the survivors had fewer muscular lesions resulting from the virus infection than the controls. In treatment experiments, the virus was inoculated on Days 1 to 3 before rFeIFN-w administration. None of the treated oysters died within a 30 d experimental period. Survivors displayed repaired lesions with fibrous tissues that were produced by enhanced agranulocytes in the body musculature. Moreover, rFeIFN-w was not toxic to akoya oysters. Thus, rFeIFN-w administration is efficacious in preventing mortality of akoya oysters with akoya-virus infection.

KEY WORDS: Japanese pearl oyster · Akoya-virus infection · Recombinant feline interferon-w · Efficacy in enhancement · Agranulocyte · Collagen fiber production

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Published in DAO Vol. 43, No. 1 (2000) on October 25
ISSN: 0177-5103. Copyright © Inter-Research, Oldendorf/Luhe, 2000