Composition of Intestinal Microbiota in Two Lines of Rainbow Trout (Oncorhynchus Mykiss) Divergently Selected for Muscle Fat Content.

Karine Ricaud,Laurence Larroquet,Sandrine Skiba-Cassy,Maxime Even,Mickael Rey,Elisabeth Plagnes-Juan,Stéphane Panserat,Edwige Quillet

doi:10.2174/1874285801812010308

Abstract

Background:Recently, studies suggest that gut microbiota contributes to the development of obesity in mammals. In rainbow trout, little is known about the role of intestinal microbiota in host physiology.Objective:The aim of this study was to investigate the link between intestinal microbiota and adiposity, by high-throughput 16S RNA gene based illumina Miseq sequencing in two rainbow trout lines divergently selected for muscle lipid content. Fish from these two lines of rainbow trout are known to have a differing lipid metabolism.Methods:Samples from the two lines (L for lean and F for fat) were collected from Midgut (M) and Hindgut (H) in juvenile fish (18 months) to compare intestinal microbiota diversity.Results:Whatever the lines and intestinal localisation, Proteobacteria, Firmicutes and Actinobacteria are the dominant phyla in the bacterial community of rainbow trout (at least 97%). The results indicate that richness and diversity indexes as well as bacterial composition are comparable between all groups even though 6 specific OTUs were identified in the intestinal microbiota of fish from the fat line and 2 OTUs were specific to the microbiota of fish from the lean line. Our work contributes to a better understanding in microbial diversity in intestinal microbiota of rainbow trout.Conclusion:Altogether, our study indicates that no major modification of the intestinal microbiota is induced by selection for muscle lipid content and associated metabolic changes. Finally, we identified members of core microbiota in rainbow trout.

Highlights

Intestinal microbiota plays a major role in animal’s health and host physiology, for example, in immunologic development or nutrient utilization
Our hypothesis was that a core microbiota would be identified in both lines, but that the diversity might be altered by the genetic characteristics which could be in relation with the different host metabolism, i.e glucose and lipid metabolisms, between the two lines (18–21)
If this concept has been very well documented in mammals, recent works in fish suggested the existence of a core microbiota in zebrafish [38], Atlantic cod [39], Atlantic Salmon [40] and rainbow trout [15]

Summary

Introduction

Intestinal microbiota plays a major role in animal’s health and host physiology, for example, in immunologic development or nutrient utilization. Microbiota can affect gut morphology and is known to stimulate the immune. Intestinal Microbiota in Two Lines of Rainbow Trout. Bacteria provide to the host nutrients, extracellular enzymes, vitamins and fatty acids, not available without the bacterial community [3]. It is well known that healthy gut microbiota is essential to promote host health and well-being and can reduce the proliferation of pathogenic bacteria [4, 5]. Studies suggest that gut microbiota contributes to the development of obesity in mammals. Little is known about the role of intestinal microbiota in host physiology

Methods

Results

Discussion

Conclusion