Probiotic Strains for Disease Management in Hatchery Larviculture of the Eastern OysterCrassostrea virginica

Abstract

Bacterial pathogens are a major cause of mortality in bivalve hatcheries, and outbreaks can result in shortages of seed supply to the grow-out industry. The use of probiotic bacteria is a potential preventative measure to limit the impact of bacterial diseases. Previous research showed that the marine bacteria Phaeobacter inhibens S4 (S4) and Bacillus pumilus RI06-95 (RI) protect larval eastern oysters (Crassostrea virginica) when challenged with the pathogens Vibrio tubiashii RE22 (now Vibrio coralliilyticus RE22) and Roseovarius crassostreae CV919-312 T. In this study, these probiotic bacteria were tested under hatchery conditions. Daily addition of S4 and RI (10 4 colony forming units (CFU)/ml) to 100-l culture tanks resulted in a significant decrease in the levels of total Vibrios in water and tank surfaces (P < 0.05), but not in oysters. Larval growth and survival was unaffected by the probiotic treatments. Larvae treated with probiotics in the hatchery showed significantly less mortality than larvae from control tanks when exposed to 10 5 CFU/ml of V. coralliilyticus RE22 for 24 h in a laboratory challenge. These results suggest that S4 and RI are safe and potentially effective tools to limit disease outbreaks in oyster hatcheries.

Bacterial Community Dynamics in an Oyster Hatchery in Response to Probiotic Treatment

“…Previous research showed that probiotic treatment with B. pumilus RI06-95 decreases levels of Vibrio spp. in the hatchery (Sohn et al, 2016a). This may be due to the production of antimicrobial secondary metabolites produced by B. pumilus RI06-95, as well as other Bacillus spp., that inhibit the growth of Vibrio spp.…”

“…Probiotics exert their beneficial effects through a variety of mechanisms, including direct pathogen inhibition, competition for nutrients, secretion of antibacterial substances, and improvement of water quality (Kesarcodi-Watson et al, 2008, 2012; Prado et al, 2010). Previous studies have shown that treatment of larval oysters in the laboratory or the hatchery with the probiotic bacterium Bacillus pumilus RI06-95 significantly increases their survival when challenged with the pathogen Vibrio coralliilyticus (Karim et al, 2013; Sohn et al, 2016a). Additionally, administration of this probiotic in a hatchery setting results in reductions in total Vibrio abundance in tank water and surfaces, compared to the control tanks (Sohn et al, 2016b).…”

Subtle Microbiome Manipulation Using Probiotics Reduces Antibiotic-Associated Mortality in Fish

“…We prepared daily cultures of the probiotic bacterial strains P. inhibens S4Sm and B. pumilus RI06-95Sm in Luria-Bertani broth containing 1.5 mg/liter streptomycin and 2% NaCl. We determined cell concentrations via serial dilution and spotting on agar plates following established protocols ( 31 , 32 , 43 ). All three bacterial strains were well known to us prior to their use in this study, and careful documentation of their growth rates, genome sequences, and virulence is outlined elsewhere ( 31 , 32 ).…”

New Insights into Pathogenic Vibrios Affecting Bivalves in Hatcheries: Present and Future Prospects

“…In the last years, different isolates of Phaeobacter gallaeciensis (formerly Roseobacter gallaeciensis ) and P. inhibens have received special attention by different research groups, due to their great spectrum of in vitro inhibition against pathogenic bacteria from aquaculture systems (Ruiz-Ponte et al, 1999; Prado et al, 2009, 2010; Kesarcodi-Watson et al, 2012; Sohn et al, 2016a,b; Zhao et al, 2016). Prado et al (2009) in experiments performed in marine water, with phytoplankton cultures and with larvae of flat oyster ( O. edulis ) and clam ( R. philippinarum ) cultures confirmed its potential use as control method in mollusc hatcheries, if its action is allowed before the pathogens reach high concentrations in the system.…”