Deciphering the mechanism of EGCG in improving ovarian function of late-laying hens: Insights from transcriptomic and metabolomic analyses.

This study aimed to systematically investigate the comprehensive effects of dietary supplementation epigallocatechin-3-gallate (EGCG) on laying performance and health in late-laying hens, with a focus on its mechanisms. This study investigated the comprehensive effects of dietary 300 mg/kg EGCG on 58-week-old late-laying Dawu Jinfeng hens (n = 180) over 21 days, using a multi-omics approach. The results showed that EGCG significantly improved laying rate, egg quality (eggshell thickness/strength, yolk color, and Haugh unit), and egg amino acid content (serine, methionine, lysine, and proline). Serological analysis revealed improved antioxidant capacity (increased SOD, GSH-Px, and CAT; decreased MDA), modulated immunity (upregulated IL-10 and downregulated TNF-α), and promoted reproductive hormones (FSH, progesterone, and estrogen). Mechanistically, EGCG downregulated TLR4/NF-κB inflammation and upregulated Nrf2 antioxidant pathways in ovarian/jejunal tissues. Additionally, it activated PI3K/Akt survival signaling, inhibited apoptosis, and maintained intestinal barrier integrity (upregulated tight junctions and mucin2). Cecal microbiota α-diversity increased, with shifts in genera increasing digestive and amino acid metabolism. Ovarian transcriptomics revealed differentially expressed genes enriching PI3K-Akt and suppressing NF-κB pathways. Metabolomics identified differentially expressed metabolites in ABC transporters, alpha-linolenic acid, and insulin signaling. Correlation networks associated microbiota, metabolites, and host phenotypes through the "gut-ovary axis." In conclusion, EGCG provides a safe and effective nutritional strategy that enhances antioxidant/immune status, modulates gut microbiota, and maintains intestinal and ovarian health through multi-pathway synergistic effects for late-laying hens, thereby improving egg quality and nutritional value. This integrated multi-omics study provides a theoretical basis for precision nutritional interventions.