Effects of tea polyphenols on intestinal barrier, antioxidant capacity, and cecal microbiota in lion-head geese

Tea polyphenols are natural bioactive compounds associated with enhanced antioxidant capacity and improved gut health in poultry. This study evaluated the effects of dietary supplementation with tea polyphenols on intestinal morphology, barrier integrity, antioxidant status, and cecal microbiota in lion-head geese. A total of 240 one-day-old male lion-head geese were randomly allocated to 2 treatments: a basal diet (control) or the same diet supplemented with 1,000 mg/kg tea polyphenols (catechin purity, 50.4%) for 18 wk (6 replicates/treatment; 20 birds/replicate). Compared with the control, dietary supplementation with tea polyphenols significantly increased villus height and villus-to-crypt ratio (V/C) in the jejunum and ileum (P < 0.05) and reduced serum lipopolysaccharide (LPS) concentration (P < 0.05), whereas serum diamine oxidase (DAO) activity did not differ (P > 0.05). In the jejunum, mRNA expression of ZO-1, Claudin-5, and Occludin was significantly upregulated (P < 0.05); in the ileum, mRNA expression of ZO-1, Claudin-5, Occludin, and E-cadherin was significantly upregulated (P < 0.05). Tea polyphenols increased jejunal total antioxidant capacity (T-AOC) and upregulated GPX1, GPX2, HO-1, and Nrf2 mRNA expression (P < 0.05). In the ileum, tea polyphenols significantly increased glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) activities, decreased malondialdehyde (MDA) content, and upregulated SOD1, GPX1, GPX2, HO-1, and Nrf2 mRNA expression (P < 0.05). Metagenomic sequencing showed lower relative abundances of Firmicutes and Verrucomicrobia at the phylum level (P < 0.05). At the genus level, tea polyphenols increased Prevotella and Subdoligranulum and decreased Oscillibacter and Desulfovibrio (P < 0.05). Functional annotation (KEGG, eggNOG, and CAZy) indicated enrichment of carbohydrate transport and metabolism, glycosyltransferases (GT), and polysaccharide lyases (PL) in the tea polyphenol group. Spearman correlation analysis indicated positive associations of Prevotella with KEGG thermogenesis and the two-component system, and of Desulfovibrio with biotin metabolism (P < 0.05). Overall, tea polyphenols promoted intestinal development, enhanced barrier- and antioxidant-related responses, and altered the composition and functional potential of the cecal microbiota, supporting improved gut health in lion-head geese.