Development and evaluation of a formulation of probiont Phaeobacter inhibens S4 for the management of vibriosis in bivalve hatcheries

• Published in: bioRxiv
• Main Authors: Takyi, Evelyn, Laporte, Jason, Sohn, Saebom, Stevick, Rebecca J, Witkop, Erin M, Gregg, Lauren, Chesler-Poole, Amanda, Small, Jessica, White, Meredith M, Giray, Cem, Rowley, David C, Nelson, David R, Gomez-Chiarri, Marta
• Format: Paper
• Language: English
• Published: Cold Spring Harbor Cold Spring Harbor Laboratory Press 28.12.2022
• Subjects: Cell culture; Cell viability; Data collection; Fertilization; Hatcheries; Larvae; Pathogens; Probiotics; Shellfish; Vibriosis
• DOI: 10.1101/2022.12.27.522043

Larval eastern oysters (Crassostrea virginica) grown in shellfish hatcheries are susceptible to bacterial diseases, particularly vibriosis. Probiotics are microbes that confer health benefits to the host and have been identified as promising tools to manage diseases in aquaculture. The marine bacterium Phaeobacter inhibens S4 (S4) protects larval eastern oysters against challenge with the bacterial pathogen Vibrio coralliilyticus RE22 (RE22). A concentrated liquid formulation of probiont S4 that maintained high cell viability after long-term storage was developed for commercial use in shellfish hatcheries. The safety and efficacy of the formulation was tested in six different trials in two hatcheries. The S4 formulation was added to C. virginica larvae culture tanks daily at 104 colony forming units (CFU)/mL from day 1 post fertilization until day 6, 12, or 14, depending on the trial. Treatment of larvae in the hatchery with the S4 formulation did not significantly affect the survival and growth of the larvae. Formulated probiont S4 treatment in the hatchery led to a significant increase in Relative Percent Survival (RPS) when larvae were subsequently challenged with the pathogen RE22 (105 CFU/mL) for 24 hours in a laboratory challenge, as compared to probiotic-untreated RE22-challenged larvae (Relative Percent Survival increase of 46 - 74%, p < 0.05). These results suggest that this novel S4 formulation is a safe, easy to use, and effective tool in preventing larval losses due to vibriosis in hatcheries.Competing Interest StatementCem Giray used to work at Kennebec River Biosciences, the company that has been licensed by the University of Rhode Island to commercialize the formulation of S4. His role was to oversee the development of the commercial upscale of S4 production and provide the probiotic for the studies. He was not involved in the hatchery trials, the data collection or the analysis. Hatchery managers provided the data on larval performance and were involved in the analysis.