Isolation of putative probionts from cod rearing environment

H. L. Lauzon*, S. Gudmundsdottir, M. H. Pedersen, B. B. Budde, B. K. Gudmundsdottir

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

Survival problems are encountered at early stages of intensive fish rearing and antibiotics are widely used to remedy the situation. Probiotics may provide a potential alternative method to protect larvae from opportunistic and pathogenic bacteria and promote a balanced environment. This study was designed to search for new probiotics to target this critical period in cod rearing. Potential probionts were selected from the natural microbiota of cod aquacultural environment. The selection was based on several criteria: pathogen inhibition potential, growth characteristics, strain identification, metabolite production and adhesion to fish cell lines. Our study demonstrated that 14% of screened bacteria (n = 188) had antagonistic properties towards fish pathogens. The majority of these isolates were Gram-positive (81%), belonging to Firmicutes (69.2%) and Actinobacteria (11.5%) phyla based on 16S rRNA gene sequencing. Only 6 (3.2%) of 188 isolates could inhibit all three pathogens tested: Vibrio anguillarum, Aeromonas salmonicida subsp. achromogenes and Vibrio salmonicida. Differences observed in activity intensity and spectrum among inhibitory isolates emphasise the need to develop probiotic mixtures for efficient prophylactic methods. Comparison of growth behaviour of inhibitory isolates and pathogens at cod rearing temperatures, metabolite production and adhesion capacity were considered for final probiont selection. Four promising isolates that could be used as a mixed supplement to rearing water were identified as putative probiotic bacteria. This study emphasises the importance and potential of lactic acid bacteria in aquaculture.

Original languageEnglish
Pages (from-to)328-339
Number of pages12
JournalVeterinary Microbiology
Volume132
Issue number3-4
DOIs
Publication statusPublished - 10 Dec 2008

Bibliographical note

Funding Information:
This work was supported by a grant from the AVS Research Fund of The Ministry of Fisheries in Iceland, being part of the PhD studies of Mrs. Lauzon funded by Matis ohf. We would like to thank Agnar Steinarsson and the staff of the Aquaculture Centre of the Marine Research Institute for their assisstance during the sampling of cod rearing systems, Eyjólfur Reynisson for the preparation of PCR products for taxonomic identification and Sólveig K. Pétursdóttir for the 16S rRNA partial sequencing analysis, as well as Páll Steinthórsson and Jarmíla Hermannsdóttir for laboratory assistance. The strain CdV41 is jointly owned and was kindly provided by UMR INRA 1014 SECALIM ENITIAA and Ifremer from Nantes in France. The fish cell lines were a generous gift from the Danish Institute for Food and Veterinary Research in Aarhus.

Other keywords

  • Adhesion
  • Antagonism
  • Cod aquaculture
  • Fish pathogens
  • Growth characteristics
  • Probiotic

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