The intestinal microbes of Atlantic salmon (Salmo salar) : implications for gut health and nutrition

• Main Author: Dehler, Carola
• Published: University of Aberdeen 2017
• Subjects: 639.3; Atlantic salmon
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715479

The aquaculture of Atlantic salmon is a fast-growing industry that has drastically increased over the last decades. Traditionally, diets for Atlantic salmon contained wild sources fishmeal and fish oil but alternatives from plants are increasingly popular substitutes. Although fish do perform well on plant rich diets in terms of growth, carnivorous fish have not evolved to cope with many anti-nutritional factors and other plant derived chemicals. In recent years the importance of intestinal microbes to the health of humans has been established by profiling the microbiota using 16S rRNA as phylogenetic marker in highthroughput sequencing studies and more recently metagenomics profiling. To date, there is sparse information on the teleost intestinal microbiota and the relationship between the microbiota and intestinal health and function. To determine baselines of “healthy” gut microbiota, the gut microbial profiles of fish from freshwater facilities and seawater facilities were analysed. Shared core microbiota were identified, suggesting that certain microbes are actively maintained by the host to fulfil minimum functionality in the gut. Salinity of the environment was identified as important determining factor for the composition of the microbiota. Furthermore, it was found that exposure to plant-based diets including faba bean protein isolates (BPI) induced enteritis in fish fed and resulted in changes of the host transcriptomics including processes related to solute transport, metabolism, tissue integrity and inflammation. The gut microbiota of the fish fed BPI was also found significantly altered and functional analysis suggest an increased genetic potential for sporulation/germination and isoflavonoid biosynthesis. Microbes identified as uniquely present and absent in the fish showing high levels of enteritis across diets could be used as future screening targets to identify onset of enteritis in fish without external signs of sickness.