Bacterial colonization of winter flounder Pseudopleuronectes americanus fed live feed enriched with three different commercial diets

Abstract

The proliferation of bacteria in intensive aquaculture systems may be responsible for poor growth and mass mortality of marine fish larvae. Essential fatty acids provided in the diet could protect larvae by modulation of the immune response via arachidonic acid (AA) and eicosapentaenoic acid (EPA). Winter flounder Pseudopleuronectes americanus larvae were fed rotifers Brachionus plicatilis enriched with three commercial diets containing different fatty acid profiles. Bacterial colonization on the gills and skin and in the intestinal lumen was evaluated at the end of the rotifer feeding period (day 26), and growth was surveyed until metamorphosis. At 26 days post hatching, larvae fed rotifers containing the higher AA content and with a higher docosahexaenoic acid (DHA) to EPA ratio showed better growth and the lowest bacterial colonization of the intestinal lumen compared to larvae fed rotifers with the lowest AA and DHA : EPA levels. AA had been selectively incorporated into the polar lipids of larvae fed the rotifers enriched with the three diets. This is the first study in winter flounder larvae to report a link between different commercial rotifer enrichments and bacterial density in intestinal lumen.

The highly variable microbiota associated to intestinal mucosa correlates with growth and hypoxia resistance of sea bass, Dicentrarchus labrax, submitted to different nutritional histories

“…Dietary HUFA are known to influence the immune status of sea bass [30], and that might also impact the association of bacteria to intestinal mucosa. Bacterial colonization of marine fish larvae may be affected by dietary fatty acids [31], but the hypothetical long-term effect of such initial colonization remains to be investigated in fish. However, the restriction of dietary HUFA at start feeding compromised durably the growth potential of sea bass, as indicated by the lower SGR observed in the individuals already challenged during the larval stages, compared to those submitted to similar deficiency only during the final period.…”

An Overview of the Use of Fatty Acids in Fish Farming Research during the Last Decade, with Particular Emphasis on Fish Quality

“…The knowledge of the relative proportion among FA, as well as of how it may be altered because of a specific experimental treatment, is of great importance for fish homeostasis, health, and physiology. For example, papers studying fish first life stages are focused more on treatment effect on fish health and FA percentages indeed help in results evaluation (Park et al 2006; Ludwig et al 2008; Seychelles et al 2011). Another example are papers focusing on dietary fish meal or fish oil replacement, mainly by plants or plant oils where FA percentages are used to evaluate farmed fish physiological status through the relative change and incorporation of FA in biological tissues (Palmegiano et al 2006; Tidwell et al 2007).…”

Microbial communities associated with early stages of intensively reared orange-spotted grouper (Epinephelus coioides)

“…It is generally accepted that the gut microbiota plays critical roles in the health and general welfare of fish larvae (Munro et al 1994;Lauzon et al 2010;Dimitroglou et al 2011;Ringø, Zhou, Olsen & Song 2012). To study the bacterial community associated with fish larvae, the general approach has been the use of cultivation-based techniques (Ringø, Strøm & Tabachek 1995;Austin 2006;Seychelles, Audet, Tremblay, Lemarchand & Pernet 2011). However, these methods only allow the investigation of cultivable bacteria, while the anaerobic bacteria and uncultivable bacteria, which may account for the majority of the bacterial population associated with fish larvae, remained largely unknown (Brunvold, Sandaa, Mikkelsen, Welde, Bleie & Bergh 2007;McIntosh et al 2008;Ringø et al 2012).…”