Molecular characterisation of Atlantic salmon gut microbiota with changing diet formulations: gut health, performance and disease resistance

Over recent years there has been increasing focus on the replacement of fish meal with plant proteins in salmon diets to improve sustainability of operations. When fed to Atlantic salmon, significant differences in growth performance between these plant p rotein sources (and compared to fishmeal) were observed, despite having similar nutrient profiles. In addition to anti-nutrients, other factors have been implicated in reduced performance. Higher levels of carbohydrates and non-digestible protein, present in some plant raw materials increase nutrient availability to the gut microbiota, resulting in changes to the population structure. Fermentation of these products by the micro-flora can result in the release of toxic metabolites affecting nutrient utilis ation, health and growth of fish. In this programme the microbiota of Atlantic salmon fed a high-inclusion fish meal diet will be characterised using advanced techniques. EWOS Innovation's well developed library of PCR sequences characterising Atlantic sa lmon gut microbiota will be used for development of quantitative RT-PCR. The effect of subsequent feeding of specific plant proteins on the microbiota and production of metabolites will be assessed in vivo and in vitro. This will be correlated to nutrient utilisation, growth performance and health of salmon. Gut micro-flora can be optimised resulting in improved health and performance of the host. In this programme an optimal gut flora will be characterised and promoted with specific raw material mix and functional nutrients. An important output will be the use of novel techniques to rapidly assess performance, suitability and value of various raw materials in salmon nutrition. The programme partners are all leaders in the field of plant protein use in aq uaculture and microbiota assessment (Aquaculture Protein Centre, Tromsø University, Alimetrics). EWOS is industry leader in the assessment and modulation of gut microbiota and commercial development of prebiotics.