The leaves of Eucommia ulmoides are rich in bioactive constituents that have potential gastrointestinal benefits for animals. In aged laying hens, intestinal health issues contribute to a significant decline in egg-laying capacity during intermediate and later stages. It remains unclear whether E. ulmoides leaf extract (ELE) can improve intestinal health and enhance egg production in elderly laying hens, and the underlying mechanisms are yet to be elucidated. Therefore, we conducted a study with 480 laying hens (65 weeks old) randomly allocated into four groups: a control group fed with the basal diet, and three treatment groups supplemented with 500, 1,000, and 2,000 mg/kg of ELE, respectively. The primary active constituents of ELE include flavonoids, polysaccharides, terpenoids, and phenolic acids. Dietary supplementation with ELE at 1,000 mg/kg (ELE1000) significantly improved laying performance and egg quality compared to the other groups. ELE1000 stimulated the maturation of intestinal epithelial cells, increased villus height, and reduced crypt depth. It also influenced the levels of proteins associated with tight junctions (claudin-1 and claudin-2) and intestinal inflammatory factors (IL-6, IL-1β, and IL-2) in different intestinal sections. Integrative analysis of serum metabolomics and gut microbiota revealed that ELE1000 improved nutrient metabolism by modulating amino acid and ubiquinone biosynthesis and influenced the abundance of intestinal microbiota by enriching pivotal genera such as Bacteroides and Rikenellaceae_RC9_gut_group. We identified 15 metabolites significantly correlated with both gut microbiota and laying performance, e.g., DL-methionine sulfoxide, THJ2201 N-valerate metabolite, tetracarbonic acid, etc. In conclusion, ELE1000 improved laying performance in elderly laying hens by affecting intestinal morphology, barrier function, microbiota, and serum metabolite profiles. These findings suggest that ELE can be a beneficial feed additive for extending the peak producing period in aged laying hens.

杜仲的叶子富含生物活性成分，对动物的胃肠道具有潜在的益处。对于老年蛋鸡来说，肠道健康问题会导致中期和后期产蛋能力显着下降。目前尚不清楚E. ulmoides叶提取物 (ELE) 是否可以改善老年蛋鸡的肠道健康并提高产蛋量，其潜在机制也有待阐明。因此，我们对 480 只蛋鸡（65 周龄）进行了一项研究，将其随机分为四组：以基础日粮喂养的对照组，以及分别补充 500、1,000 和 2,000 mg/kg ELE 的三个治疗组。ELE 的主要活性成分包括类黄酮、多糖、萜类化合物和酚酸。与其他组相比，日粮中添加 ELE 1,000 mg/kg (ELE1000) 显着改善产蛋性能和鸡蛋质量。ELE1000刺激肠上皮细胞的成熟，增加绒毛高度，减少隐窝深度。它还影响不同肠道切片中与紧密连接相关的蛋白质（claudin-1和claudin-2）和肠道炎症因子（IL-6、IL-1β和IL-2）的水平。血清代谢组学和肠道微生物群的综合分析表明，ELE1000 通过调节氨基酸和泛醌生物合成改善营养代谢，并通过富集拟杆菌属和Rikenellaceae_RC9_gut_group等关键属来影响肠道微生物群的丰度。我们鉴定出 15 种与肠道菌群和产蛋性能显着相关的代谢物，例如 DL-蛋氨酸亚砜、THJ2201 N-戊酸代谢物、四碳酸等。 总之，ELE1000 通过影响肠道形态、屏障功能来改善老年蛋鸡的产蛋性能、微生物群和血清代谢物概况。这些研究结果表明，ELE 可以成为一种有益的饲料添加剂，有助于延长老年蛋鸡的高峰生产期。