XOS-based prebiotic complex improves laying performance and attenuates inflammation-driven gut injury and dysbiosis under LPS challenge

Xylooligosaccharides (XOS) are prebiotics that promote gut health and microbial balance in poultry, but their efficacy under immune-inflammatory stress such as that induced by lipopolysaccharide (LPS) challenge, remains uncertain. To enhance their functional breadth, a XOS-based prebiotic complex (XOS-PC), combining diverse oligosaccharides and fermentable fibers, was utilized. This study investigated the effects of XOS-PC on productivity, intestinal integrity, and inflammation in laying hens under both basal and lipopolysaccharide (LPS)-challenged conditions. A total of 600 Dawu Jinfeng laying hens (35 weeks) were assigned to five dietary groups receiving 0, 0.05%, 0.1%, 0.2%, or 0.4% XOS-PC for 12 weeks. At the end of the trial, the 0.2% XOS group exhibited optimal laying performance and was selected, along with the control group, for the subsequent LPS challenge. A total of 32 birds were selected from both the control (n = 16) and the 0.2% XOS-PC group (n = 16). Within each group, half of the birds (n = 8) were administered Escherichia coli LPS, while the other half (n = 8) received PBS at a dosage of 1 mg/kg body weight, intravenously. At 6 hours post-injection, samples were collected for intestinal morphology, gene expression, and ileal microbiota profiling. Supplementation of 0.2% XOS-PC significantly improved egg production, feed conversion ratio, and yolk pigmentation, reduced serum AST, and enriched ileal microbial diversity, with marked increases in Lactobacillaceae (P < 0.05). Following LPS exposure, XOS-PC preserved villus architecture, evidenced by increased ileal VH and VH/CD ratio (P < 0.05). In the ileal mucosa, XOS-PC supplementation upregulated CLDN1, CLDN5, TLR2, and TLR4 gene expression while suppressing TNF-α (P < 0.05), indicating enhanced barrier function and attenuated inflammatory signaling. Microbiota analysis revealed increased alpha diversity, distinct beta diversity, elevated Lactobacillaceae, and reduced Fusobacteria and Sphaerochaeta (P < 0.05). Correlation analysis revealed positive association between Lactobacillus with villus height and gut barrier genes, while Fusobacteria and Sphaerochaeta correlated inversely with epithelial integrity and positively with TNF-α. Collectively, this study demonstrates that a structurally enriched XOS-based prebiotic complex enhances productivity, reinforces gut integrity, and reprograms microbiota under both physiological and immune-stressed states, offering a novel precision-nutritional solution for poultry resilience.