Modulatory effects of Boletus edulis on the gut microbiota in Atlantic salmon (Salmo salar) utilizing an artificial teleost gut model

Background: In aquaculture, several functional mushrooms have been efficiently used as prebiotics, impacting gut microbiota, increasing growth, and delivering antioxidant advantages to a variety of finfish species. However, the potential of Boletus edulis, the ‘porcini’ or ‘penny bun’ to influence the gut microbiota of Salmo salar has yet to be studied. Here, we investigated the prebiotic effect of Boletus edulis extract (BEE) on the gut microbiota of farmed Atlantic salmon via an in vitro gut model (SalmoSim). Results: Notable changes in the production of short-chain fatty acids and microbial diversity were observed upon the addition of BEE. In particular, increased fiber fermentation was suggested by the decreasing concentrations of ammonia and increasing levels of acetate and propionate. Moreover, the 10% BEE improved the absorption of amino acids and increased the digestibility of crude protein, promoting a more diverse microbial community and reducing the accumulation of nitrogenous waste. Conclusions: The results of the present study revealed that the addition of BEE efficiently altered the gut microbiota, increasing microbial diversity, supporting beneficial short-chain fatty acid synthesis, and improving nutritional absorption in Atlantic salmon.