Dietary Chlorogenic Acid-Rich Green Coffee Bean Extract Improves Laying Performance and Antioxidant Status in Heat-Stressed Laying Hens

Cyclic heat stress compromises egg production and antioxidant defenses in laying hens. The present study employed a short-term, 14-day cyclic heat-stress model to evaluate whether dietary supplementation with a chlorogenic acid-rich green coffee bean extract could mitigate these effects. Before initiation of the heat-stress experiment, all hens were maintained under thermoneutral conditions and received the basal diet without the extract. Following 1 week of adaptation and 4 weeks of thermoneutral feeding, 240 approximately 50-week-old Jingfen No. 8 hens were allocated to a thermoneutral control, a heat-stress control, or heat-stressed groups receiving 100 or 200 mg/kg extract containing 70% chlorogenic acid, with four independent replicates of 15 hens each (60 hens per treatment). Heat-stressed hens were subjected to a 14-day cyclic heat-stress challenge at 32–35 °C for 9 h/day. Heat stress decreased average egg weight and laying rate, increased serum malondialdehyde, and reduced total antioxidant capacity (p < 0.05). Both supplemented groups improved average egg weight and laying rate, reduced malondialdehyde and total cholesterol, and increased total antioxidant capacity relative to heat-stressed controls (p < 0.05). Supplementation altered hepatic expression of genes associated with proliferation, apoptosis, and autophagy. Exploratory metabolomics detected changes in the 100 mg/kg group but not the 200 mg/kg group relative to heat-stressed controls. The extract partially mitigated production and antioxidant impairments during cyclic heat stress.