Resveratrol supplementation mitigates age-related declines in egg production, quality, and ovarian health of laying hens

This investigation focused on how resveratrol (RES) influences egg production, quality, reproductive hormone, and antioxidant capacity in laying hens of different ages. A completely randomized experiment was conducted with a 2 × 2 factorial arrangement of treatments, including 47- and 67-week-old Lohmann Gray laying hens (initial body weight 1.58 ± 0.12 kg) and two dietary treatments (0 and 400 mg/kg RES) for 12 weeks. The study involved 216 hens, randomly allocated with nine replicates per treatment and six hens per replicate. Results indicated that older (67-week old) laying hens exhibited a higher feed-to-egg ratio and defective egg rate during weeks 1 to 12 than 47-week-old without RES supplementation (interaction, P = 0.012 and P = 0.047), while addiction with RES significantly reduced feed-to-egg ratio in 67-week-old hens ( P < 0.05). Significant interactions between age and RES were observed for egg quality parameters including albumen height, eggshell strength, and eggshell thickness ( P < 0.05). The RES supplementation improved feed efficiency and egg quality ( P < 0.05), particularly in older hens. Haugh unit was restored by RES in aged birds during weeks 9 to 12 (interaction, P = 0.023). Plasma levels of melatonin (MT), estradiol (E2), and anti-Müllerian hormone (AMH) also showed significant interactions ( P < 0.05), with RES increasing these hormones only in older hens. Age and RES supplementation had a significant interaction for ovarian malondialdehyde (MDA) levels ( P < 0.001), where RES significantly reduced MDA concentrations in older hens ( P < 0.05). At the molecular level, RES significantly upregulated the mRNA expression of heme oxygenase-1 ( HO-1 ), nuclear factor erythroid 2-related factor 2 ( Nrf2 ), and NAD(P)H quinone oxidoreductase 1 ( NQO1 ; P < 0.01), while aging upregulated tumor necrosis factor- α ( TNF-α ) expression ( P = 0.018). RES also suppressed IL-6 , IL-8 , TNF-α , and nuclear factor κ-light-chain-enhancer of activated B cells ( NF-κB ) expression, and enhanced anti-apoptotic genes B-cell lymphoma-extra-large and B-cell lymphoma 2 expression ( P < 0.05). In conclusion, RES supplementation (400 mg/kg) effectively improved laying performance, egg quality, and oxidative and inflammatory responses in laying hens, suggesting its potential as a nutritional strategy to support laying performance during the late production stages.