Role of Simulated Nannochloropsis gaditana Digests in Shaping Gut Microbiota and Short-Chain Fatty Acid Levels

The connection between gut microbiota and factors like diet is crucial for maintaining intestinal balance, which in turn impacts the host's overall health. Nannochloropsis gaditana microalgae is a sustainable source of bioactive compounds, mainly known for its used in aquaculture and extraction of bioactive lipids, with potential health benefits whose effects on human gut microbiota are still unknown. Therefore, the goal of this work was to assess the impact of N. gaditana on human gut microbiota composition and derived metabolites by combining the INFOGEST protocol and in vitro colonic fermentation process to evaluate potential effects on human gut microbiota conformation through 16S rRNA gene sequencing and its metabolic functionality. The results have demonstrated the ability of the digests from N. gaditana to significantly modify gut microbiota composition, promoting an increase in beneficial bacterial genera such as Akkermansia, Butyricicoccus, Eisenbergiella, Lachnoclostridium, and Marvinbryantia, in contrast to inulin, after 48 h of colonic fermentation. Additionally, the digests increased the levels of both major and minor short-chain fatty acids (SCFAs), particularly butyric and valeric acids, considered as intestinal biomarkers, and increased ammonium production. This research has demonstrated, for the first time, the potential of N. gaditana microalgae as a sustainable agent for influencing the composition and functionality of human gut microbiota.