Integrated gut microbiota and metabolomics analysis of the effect of pomegranate peel powder on intestinal inflammation in broilers induced by high non-starch polysaccharides

Abstract

Background Non-starch polysaccharides (NSPs) support gut health at low levels but may impair nutrient absorption and trigger inflammation when consumed excessively. Pomegranate peel powder (PPP), rich in punicalagin, ellagic acid, gallic acid, and quercetin, exerts intestinal protective effects by inhibiting pathogens, protecting probiotics, reducing inflammation, and strengthening the intestinal barrier. It shows potential for alleviating conditions such as infectious diarrhea, colitis, and metabolic intestinal disorders. Methods This study investigates the mechanisms by which PPP mitigates NSP-induced intestinal inflammation in broilers. An inflammation model was established using a basal diet supplemented with 30% rice bran, validated through reduced growth performance, altered intestinal morphology, and increased inflammatory marker expression. Broilers receiving the high-NSP diet were supplemented with varying concentrations of PPP. An optimal dose of PPP (6 g/kg) was identified based on improvements in growth performance, intestinal inflammatory factor expression levels, and intestinal morphology. Further evaluation of this dose was carried out using 16S rRNA gene sequencing and LC-MS to evaluate its effect on the intestinal microbiota and fecal metabolites. Results PPP supplementation significantly increased the relative abundance of Proteobacteria, Phascolarctobacterium faecium, Bacteroides uniformis, and Muribaculaceae, while reducing Firmicutes, Fusobacteriota, and Fusobacterium mortiferum. Metabolomic profiling identified 92 differential metabolites between PPP supplementation group and inflammation model group. PPP supplementation restored 25 metabolites change induced by NSPs, including geniposidic acid, succinic acid and 2,6-Dimethoxy-1,4-benzoquinone. KEGG analysis showed that oxidative phosphorylation, phenylalanine metabolism, and carbon metabolism are the most significantly enriched pathways. Conclusion PPP could alleviate the inflammatory response and intestinal damage induced by NSPs, and promote the growth of broilers by strengthening the intestinal barrier and reducing the levels of inflammatory factors, as well as improving the intestinal flora and key functional metabolites.