Modulation of gut microbiota composition and predicted metabolic capacity after nutritional programming with a plant-rich diet in Atlantic salmon (Salmo salar): insights across developmental stages.

• Published in: Animal Microbiome
• Main Authors: Tawfik, Marwa Mamdouh, Lorgen-Ritchie, Marlene, Król, Elżbieta, McMillan, Stuart, Norambuena, Fernando, Bolnick, Daniel I, Douglas, Alex, Tocher, Douglas R, Betancor, Mónica B, Martin, Samuel A M
• Format: Article in Journal/Newspaper
• Language: English
• Published: BioMed Central 2024
• Subjects: Atlantic salmon; First feeding; Fishmeal; Intestinal microbiota; Metabolic programming; Microbio; Nutritional history; Nutritional programming; Plant-based diet; Vegetable-based diet; Salmo salar
• Online Access: https://doi.org/10.1186/s42523-024-00321-8; https://pubmed.ncbi.nlm.nih.gov/38951941; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11218362/

To promote sustainable aquaculture, the formulation of Atlantic salmon (Salmo salar) feeds has changed in recent decades, focusing on replacing standard marine-based ingredients with plant-based alternatives, increasingly demonstrating successful outcomes in terms of fish performance. However, little is known about how these plant-based diets may impact the gut microbiota at first feeding and onwards. Nutritional programming (NP) is one strategy applied for exposing fish to a plant-based (V) diet at an early stage in life to promote full utilisation of plant-based ingredients and prevent potential adverse impacts of exposure to a plant-rich diet later in life. We investigated the impact of NP on gut microbiota by introducing fish to plant ingredients (V fish) during first feeding for a brief period of two weeks (stimulus phase) and compared those to fish fed a marine-based diet (M fish). Results demonstrated that V fish not only maintained growth performance at 16 (intermediate phase) and 22 (challenge phase) weeks post first feeding (wpff) when compared to M fish but also modulated gut microbiota. PERMANOVA general effects revealed gut microbiota dissimilarity by fish group (V vs. M fish) and phases (stimulus vs. intermediate vs. challenge). However, no interaction effect of both groups and phases was demonstrated, suggesting a sustained impact of V diet (nutritional history) on fish across time points/phases. Moreover, the V diet exerted a significant cumulative modulatory effect on the Atlantic salmon gut microbiota at 16 wpff that was not demonstrated at two wpff, although both fish groups were fed the M diet at 16 wpff. The nutritional history/dietary regime is the main NP influencing factor, whereas environmental and host factors significantly impacted microbiota composition in M fish. Microbial metabolic reactions of amino acid metabolism were higher in M fish when compared to V fish at two wpff suggesting microbiota played a role in digesting the essential amino acids of M feed. The excessive mucin O-degradation revealed in V fish at two wpff was mitigated in later life stages after NP, suggesting physiological adaptability and tolerance to V diet. Future studies are required to explore more fully how the microbiota functionally contributes to the NP.