Abstract
Oyster larvae reared in hatcheries on the U.S. West coast often experience severe Vibrio coralliilyticus-related mortalities early in their development. Current treatment options for these molluscs are not available or feasible; however, for decades, probiotics have been successfully used in finfish and crustacean shellfish culture. Consequently, the objectives of this work were to 1) isolate marine bacteria from oysters and evaluate their protective activity against Vibrio coralliilyticus infection of Pacific oyster (Crassostrea gigas) larvae, and 2) to determine the long-term effects of probiotic additions on growth and metamorphosis of larval Pacific and Kumamoto oysters (C. sikamea). A combination of three probiotic strains applied once 24 hours post-fertilization was more effective in improving survival of larval C. gigas exposed to lethal concentrations of V. coralliilyticus strain RE22, compared with separate additions of individual probiotics. In addition, a single application of the probiotic combination to one-day-old larvae increased the larval metamorphosis success of C. sikamea and both the Midori and Myiagi stocks of C. gigas. These results suggest that probiotics are effective at preventing disease and can significantly improve performance of oyster larvae, using a single application early in their development.
Highlights
A novel treatment of three combined marine probiotic bacterial isolates improved acute survival of early Pacific oyster larvae exposed to a lethal concentration of the highly virulent V. coralliilyticus strain RE22.
A single dose of combined probiotics added to one-day-old Pacific oyster larvae improved their subsequent growth at 14 days post egg-fertilization.
Metamorphosis success was increased in two stocks of the Pacific oyster, Crassostrea gigas, as well as the Kumamoto oyster, C. sikamea, after a single dose of the combined probiotics was added to one-day-old larvae.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
↵1 JL. Trans Balauring, Desa Merdeka, Kecamatan Lebatukan, Kab. Lembata, 86681 NTT, Indonesia
