Hoj, Lone, Bourne, David G., and Hall, Michael R. (2009) Localization, abundance and community structure of bacteria associated with Artemia: effects of nauplii enrichment and antimicrobial treatment. Aquaculture, 293 (3-4). pp. 278-285.

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Abstract

The use of live feeds presents a biosecurity risk for aquaculture due to the potential for inadvertent introduction bacterial pathogens. Reared Artemia nauplii constitute the most commonly used live feed for larval species including fish, crustaceans, and molluscs. We therefore analyzed the localization, abundance community structure of bacteria associated with Arternia nauplii using a combination of microscopy-based and molecular methods. Most bacteria were localized in the nauplii gut, with external having limited bacterial colonization. The bacterial community of newly hatched nauplii was dominated populations related to uncultured members of Gammaproteobacteria and Planctomycetales. Enrichment of temia nauplii for 24 h with lipid concentrates or a mixture of microalgae generally increased their bacterial relative to newly hatched nauplii, and in one case the enrichment process shifted the bacterial towards Vibrio spp. Antimicrobial treatment using a combination of formalin, Virkon (R) S and a mixture antibiotics reduced the load of culturable bacteria as expected, but strains of the genera Vibrio, Micrococcus, Brevundimonas, Sphingomonas, and Rhizobium were isolated from treated nauplii. Surprisingly, molecular methods revealed that the antimicrobial treatment caused a relative enrichment of DNA from spp. in the bacterial DNA pool. This demonstrated that Vibrio spp. were relatively more resistant to the than other members of the bacterial community, a fact that was not revealed by the culture-based While it is unknown whether the detected DNA originated in viable cells, a low-abundant but bacterial community would represent a substantial biosecurity risk for any hatchery The results from this therefore support the use of disinfected Artemia nauplii in combination with probiotics to ensure that rather than potentially pathogenic bacteria dominate the bacterial community added to rearing tanks of larvae.

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