The intestines from Chinese seabass (Lateolabrax maculatus) for 16s sequencing Raw sequence reads

Plant-derived condensed tannins exhibit strong bioactivity of antioxidant, immunostimulation and intestinal protection, but little is konwn about the mechanism of action. Condensed tannins are consist of catechins monomers (e.g. catechin, epicatechin and epigallocatechin), whereas the contribution of monomers to the bioactivity of condensed tannins is unknown. Here, an intestinal cell oxidative stress model and an animal feeding experiment were set up to evaluate the effects of condensed tannins and catechins on anti-oxidative stress and intestinal health of Lateolabrax maculatus. We found condensed tannins and catechins alleviate hydrogen peroxide-induced cell injury by activating Nrf2 factor and improving antioxidant and immune capacities. Catechin and epicatechin exhibit similar therapeutic effect with condensed tannins. Dietary condensed tannins and catechins enhanced intestinal antioxidant ability and increased the abundance of intestinal Firmicutes, Proteobacteria and Bacteroidetes to oxidative stress tolerant. 1 g/kg of condensed tannins and catechin promoted intestinal total antioxidant capacity, but slightly induced intestinal injury mainly due to increased intestinal permeability and inhibited digestion of fish. In summary, condensed tannins and catechins protect intestine from oxidative stress and improve intestinal antioxidant capacity by stimulating antioxidant enzyme system and bacterial microbiome. Catechin and epicatechin show similar or superior antioxidant activity than condensed tannins.