More attention has been paid in recent times to the application of Broussonetia papyrifera (BP) silage in ruminants, owing to its nutritional value. This study aimed to characterize the functionality of fermented BP and preliminarily explore its dietary effects on the gut health of laying hens. In this study, we characterized the antioxidant and antibacterial activities, bioactive compound profile, and bacterial community in Lactobacillus plantarum-fermented BP (FBP), as well as its dietary effects on intestinal morphology, microbiota and gene expression of laying hens. Improved contents of protein, total polyphenol and flavonoids as well as antioxidant and antibacterial activities were found after fermentation of BP. Untargeted metabolomics displayed more abundant apigenin, luteolin, diosmetin, and quercetin within the FBP, which may contribute to its functionality. Microbiome demonstrated increased abundance of Firmicutes at the expense of Cyanobacteria phylum, accompanied with raised levels of Lactobacillus genus. The results of a feeding trial showed dietary FBP supplementation increased the serum superoxide dismutase, but down-regulated gene expression of aryl hydrocarbon receptor (AhR), mucin2, and ZO-2, without obviously affecting the intestinal morphology and colonic microbiota. These findings suggest that FBP warrants further investigation as it may serve as a functional dietary supplement in laying hen feed.

Background/objectives: Policosanol, a bioactive compound derived from rice bran wax, has demonstrated potential for alleviating stress, yet its underlying mechanisms remain elusive. This study aimed to elucidate its role in mitigating chronic stress-induced growth impairment and to explore its interactions with the gut microbiota and metabolomics. Methods: Male rats were subjected to a 4-week chronic restraint stress protocol with or without policosanol supplementation (2 mg/kg/day). Systemic responses were evaluated by measuring growth parameters (including weight gain and muscle mass), serum biomarkers [cortisol and catecholamines (CA)], 16S rRNA sequencing (for cecal microbiota analysis), and LC-MS metabolomics (for cecal metabolite profiling). Results: Stress induced a significant reduction in weight gain (−11.0%, p < 0.05) and a marked elevation of serum cortisol (+86.2%) and CA (+88.3%, both p < 0.05). Policosanol treatment restored weight gain to 85.5% of control levels ( p < 0.05) and reduced cortisol and catecholamine levels by 29.5% and 26.8%, respectively (both p < 0.05). Stress-induced alterations in gut microbiota included a 4.1-fold increase in p_Verrucomicrobiota and a 3.8-fold increase in g_Akkermansia , along with metabolite changes such as a 4.2-fold elevation in Proscillaridin and a 65% decrease in Phenylacetylglutamine (PAGln) (both p < 0.05). Policosanol supplementation normalized gut microbiota composition (p_Verrucomicrobiota decreased by 36%, p < 0.05) and restored metabolite levels (PAGln increased by 80%, p < 0.01). Negative correlations were observed between g_Akkermansia abundance and weight gain ( p < 0.01), while PAGln positively correlated with growth ( p < 0.05) and negatively correlated with GSH-Px ( p < 0.001), cortisol ( p < 0.001), and CA ( p < 0.001). Moreover, the g_Bacteroides –PAGln axis exhibited a strong interaction ( p < 0.001). Conclusion: Policosanol mitigates stress-induced growth impairment by modulating gut microbiota (e.g., reducing p_Verrucomicrobiota and g_Akkermansia abundances) and restoring metabolite levels (e.g., increasing PAGln). The coregulation of the gut microbiota and metabolome was highlighted by a strong correlation between g_Bacteroides and Phenylacetylglutamine (PAGln), suggesting a potential functional interaction that may contribute to the anti-stress effects of policosanol, though causality remains to be established.