Exploring the hologenome concept in marine bivalvia: haemolymph microbiota as a pertinent source of probiotics for aquaculture

• Published in: FEMS microbiology letters 2014-01, Vol.350 (1), p.107-116
• Main Authors: Desriac, Florie, Le Chevalier, Patrick, Brillet, Benjamin, Leguerinel, Ivan, Thuillier, Benoît, Paillard, Christine, Fleury, Yannick
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; antibacterial; Aquaculture; Archipelagoes; Biodiversity and Ecology; Bivalvia; Bivalvia - microbiology; Cell Survival; Crassostrea; Deep sea; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; DNA, Ribosomal - chemistry; DNA, Ribosomal - genetics; Dose-Response Relationship, Drug; Environmental Sciences; France; Gram-Negative Bacteria - drug effects; Gram-Positive Bacteria - drug effects; Hemocytes - drug effects; hemolymph; Hemolymph - microbiology; Marine; Microbial Sensitivity Tests; Microbiology; Microbiota; Mollusks; Oysters; Pathogens; Phylogeny; probiotic; Probiotics - isolation & purification; Pseudoalteromonas; Pseudoalteromonas - chemistry; Pseudoalteromonas - genetics; Pseudoalteromonas - isolation & purification; RNA, Ribosomal, 16S - genetics; Shellfish; Survival; Tapes rhomboides
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/1574-6968.12308

Abstract Haemolymph-associated microbiota of marine bivalves was explored for antibacterial activity against important aquaculture pathogens. A collection of 843 strains were cultured from the haemolymph of four bivalve species (Crassostrea gigas, Mytilus edulis, Pecten maximus and Tapes rhomboides) collected by deep-sea diving in the Glenan Archipelago (France). Cell-free culture supernatants were investigated for antibacterial activity using the well-diffusion assay. About 3% of haemolymph-associated cultivable bacteria displayed antibacterial activity toward Gram-negative pathogens. Among the active bacteria, Pseudoalteromonas strains exhibited the highest antibacterial activity. The cell-free culture supernatant of one of them, named hCg-51, was able to inhibit the growth of bacterial pathogens even after drastic dilution (1 : 1024). Hemocyte survival was not significantly altered in the presence of the haemolymph-associated strains assayed. Moreover, a dose-dependent beneficial effect on hemocyte survival rates was observed with the hCg-51 strain. These results suggest that haemolymph microbiota may participate in bivalve protection and therefore confer a health benefit on the host. As a result, the results highlight bivalve haemolymph microbiota as a promising novel source for aquaculture probiotics. This work also gives a first insight into the contribution of the haemolymph-associated microbiota as part of the bivalve ‘hologenome’. Isolation of new Pseudoalteromonas strains exhibiting a high probiotics potential was the result of the first exploration of microbiota from bivalvia hemolymph for antibacterial activity and cytotoxic effect.