摘要Background Systemic inflammatory responses and oxidative stress occur in laying hens during the aging process,particularly during the post-peaking laying period,which generally result in multi-organ damages,leading to sig-nificant declines in egg performance and quality.Chlorogenic acid(CGA)-enriched extract from Eucommia ulmoides leaves has anti-inflammatory and antioxidant activities.However,the mechanisms underlying whether and how CGA alleviates systemic inflammatory responses and oxidative stress to improve egg performance and quality in post-peaking laying hens remain unclear.In this study,the potential regulatory mechanisms of CGA in alleviating inflam-matory responses and oxidative stress along the gut-liver axis were investigated.A total of 360 55-week-old Hy-line white-laying hens were randomly selected and divided into four groups.The hens in the four groups were fed a basal diet(CON)or basal diets supplemented with 200,400,and 800 mg/kg of CGA(CGA200,CGA400,and CGA800,respec-tively)for 10 weeks.Results The results demonstrated that CGA significantly alleviated intestinal and hepatic damages resulting from sys-temic inflammatory responses and oxidative stress,thereby improving the laying performance and egg quality of post-peaking laying hens.CGA reduced systemic inflammation by improving intestinal barrier function and modu-lating inflammation-associated microbiota(Blautia and Megamonas),thus inhibiting endotoxin translocation.CGA can also reduce oxidative stress by upregulating the NRF-2 pathway-related genes and increasing antioxidant enzyme activities in the liver.The results of transcriptome sequencing revealed that CGA promoted lipid metabolism by regu-lating hepatic adipocytokine pathway-related genes/protein and reduced the inflammatory responses and apoptosis in liver by regulating PI3K/AKT pathway-related genes/proteins,which was also verified by qPCR and western blotting.Conclusion CGA alleviated multi-organ damages and dysfunction by suppressing the systemic inflammatory responses and oxidative stress in post-peaking laying hens,thereby improving egg performance and quality.The opti-mal dose of CGA is 400 mg/kg in this experiment.These results provide a sound theoretical basis for the application of CGA as an exogenous animal feed additive for laying hens.