Isolation of putative probionts from cod rearing environment

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

  • H.L. Lauzon
  • S. Gudmundsdottir
  • M.H. Pedersen
  • Birgitte Bjørn Budde
  • B.K. Gudmundsdottir

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 naturalmicrobiota 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.

OriginalsprogEngelsk
TidsskriftVeterinary Microbiology
Vol/bind132
Udgave nummer3-4
Sider (fra-til)328-339
Antal sider12
ISSN0378-1135
DOI
StatusUdgivet - 2008

ID: 8117077