Bamboo leaf flavonoids counteract lipopolysaccharide-induced gut dysfunction in aging laying hens through microbiota and metabolic reprogramming

Laying hens face exacerbated intestinal damage from bacterial lipopolysaccharide (LPS) with aging due to physiological decline and microbiota dysbiosis. Bamboo leaf flavonoids (BLF) have shown anti-inflammatory and immunomodulatory bioactivity. In this study, a total of 360 aging hens were randomly divided into control (CON), BLF supplementation group (BLF), LPS challenge group (LPS), and BLF protective group (BLP) to investigate the effect of BLF on intestinal barrier functions, inflammatory responses, and gut microbiota in aging laying hens. The results revealed that the BLF group showed improved jejunal villus structure, enhanced intestinal barrier function, reduced intestinal permeability, and a milder inflammatory response as compared with the control hens. Notably, LPS challenge induced jejunal villus atrophy, barrier dysfunction, increased intestinal permeability and intensified inflammatory response. BLF supplementation ameliorated LPS-induced gut dysfunction by restoring the villus morphology, enhancing barrier function and suppressing inflammatory response. Cecal microbiota analysis revealed that BLF could reduce pathogenic taxa (Elusimicrobiota, Verrucomicrobiota, and UCG-005) and enrich the beneficial genera (Lactobacillus and Bacteroidales) in cecum. Untargeted metabolomics revealed BLF rectified LPS-induced metabolic disturbances, particularly in phenylalanine/tyrosine/tryptophan biosynthesis and secondary bile acid pathways. Overall, BLF could mitigate LPS-induced intestinal dysfunction in aging hens by restoring barrier integrity, suppressing pro-inflammatory cytokines, reshaping gut microbiota and metabolic reprogramming. These coordinated improvements in barrier function, microbial balance, and metabolite profiles highlight BLF's potential as a feed additive to enhance intestinal resilience in aging poultry under inflammatory stress.