Probiotic activity of Aeromonas media on the Pacific oyster, Crassostrea gigas, when challenged with Vibrio tubiashii

The ability of BUS-(bacteriocin-like inhibitory substance)-producing Aeromonas media, strain A199, to act as a probiotic was assessed on the host animal, Crassostrea gigas, by testing whether or not strain A199 could prevent death of the oyster larvae when challenged with Vibrio tubiashii. Whereas larvae, challenged with the Vibrio, died within 5 days, the presence of both the pathogen and the probiotic strain, together, did not affect the viability of the larvae over the same time period. The viability of larvae challenged with A199 alone was also unaffected. In addition, A199 exhibited antagonistic activity against a wide range of fish/shellfish pathogens in vitro. These findings have important, economic implications for those engaged in the oyster producing industry where heavy losses can be experienced as a result of an infectious outbreak. (C) 1998 Published by Elsevier Science B.V. All rights reserved.