Dietary silaged Broussonetia papyrifera improves laying performance and intestinal health by modulating gut microbiota and metabolic pathways in aged laying hens

Broussonetia papyrifera (BP) contains various bioactive compounds that may benefit animals when silaged. Intestinal problems, such as inflammation, barrier impairment, and microbial dysbiosis in aged laying hens, in aged laying hens induce an decrease in egg production This study examined the effects of dietary silaged Broussonetia papyrifera (SBP) on production and intestinal health. A total of 240 Hy-Line Brown laying hens (65 weeks old, similar laying rates and body weights) were allocated to two groups (8 replicates of 15 hens each): a control group fed a basal diet and an SBP group fed the basal diet supplemented with 4% SBP. Compared with the control, the SBP group showed higher laying rates, lower dirty egg rates, and greater egg weight, yolk color, eggshell strength, and eggshell weight at d 56, though Haugh units and yolk ratios were lower. SBP supplementation was associated with greater villus height, lesser crypt depth, stronger epithelial maturation, and modulated tight junction protein mRNA expression (ZO-1, ZO-2, claudin-2) across intestinal segments, along with higher TLR4 in the duodenum and jejunum and IL-6 in the ileum. Serum metabolomics identified 159 differentially abundant metabolites (101 upregulated, 58 downregulated), enriched in steroid hormone biosynthesis, purine metabolism, and unsaturated fatty acid biosynthesis pathways. Integrated microbiota-metabolome analysis indicated SBP shifted gut microbiota composition, increasing beneficial genera such as Bacteroides and Verrucomicrobiota. Ten metabolites, including Gly-Tyr-Ala, tomatidine, ingenol-3-angelate, and pyrithioxin, correlated strongly with microbiota, laying performance, and eggshell quality. Overall, SBP supported laying performance in aged hens by affecting intestinal morphology, barrier function, microbiota composition, and serum metabolite profiles, indicating its potential as a feed additive to extend productive life.