Nutritional Intervention With Perennial Ryegrass Modulates UA Metabolism in Goslings via Gut Microbiota-Antioxidant...

Hyperuricemia (HUA) is a metabolic disorder characterized by excessive uric acid (UA) accumulation resulting from increased hepatic production and impaired renal and intestinal excretion. Nutritional interventions using plant-based feed resources rich in bioactive compounds have shown promise in regulating urate metabolism in poultry. Perennial ryegrass, a forage abundant with dietary fiber and polyphenols, exhibits antioxidant and anti-inflammatory properties that may modulate UA metabolism. In the present study, Wanpu goslings were used to investigate the protective effects of perennial ryegrass against HUA and UA-induced oxidative stress. In the present study, Wanpu goslings were assigned to three dietary treatments: (i) concentrate-only diet (CD), (ii) concentrate diet supplemented with 30% perennial ryegrass (70% concentrate:30% ryegrass; GD1), and (iii) concentrate diet supplemented with 50% perennial ryegrass (50% concentrate:50% ryegrass; GD2). While CD and GD1 supported higher average daily gain compared to GD2. Inclusion of perennial ryegrass significantly reduced serum UA and creatinine (Cr) levels. Noticeably, ryegrass supplementation decreased hepatic xanthine oxidase (XOD) activity and enhanced the expression of urate transporters (ABCG2, OAT1, and OAT3) in intestinal and renal tissues, indicating improved urate excretion. Moreover, perennial ryegrass improved intestinal morphology and barrier integrity, attenuated oxidative stress through activation of the Nrf2-ABCG2 signaling pathway, increased antioxidant enzyme activities, and reduced pro-inflammatory cytokine levels. Additionally, 16S rRNA sequencing revealed enrichment of beneficial microbial genera, including Alistipes, Ruminococcus, and Akkermansia, in ryegrass-fed goslings. Metabolomic profiling further demonstrated decreased concentrations of HUA-associated metabolites xanthine, hypoxanthine, and inosine, and elevated levels of bioactive phenolic compounds such as caffeic acid, kaempferol, quercetin, and ferulic acid. Network analysis suggested antagonistic interactions between polyphenolic metabolites and urate-promoting intermediates. These findings indicate that moderate inclusion of perennial ryegrass (30%) in concentrate-based diets may serve as a sustainable nutritional strategy to modulate UA metabolism, antioxidant capacity, and gut microbial composition in intensive goose production systems.