Dietary phytogenic modulation of inflammatory biomarkers in the ovary and liver underlies improved productivity in laying hens

• Dietary phytogenic blend (PB) improved productive performance in laying hens • Ovarian & hepatic homeostasis-related gene expression was beneficially modulated by dietary PB • The PB inclusion level of 750 mg/kg diet displayed the optimal benefits This study evaluated the effects of different dietary inclusion levels of a phytogenic blend (PB) containing carvacrol, thymol and olive polyphenols, on productive performance and inflammatory (Nuclear factor-kappa B; NF-κB) responses in the ovary and liver of laying hens. Depending on the PB inclusion level (0, 250, 750, 1000 and 1500 mg/kg feed), 385 Hy-Line Brown hens (21 weeks old) were assigned to 5 dietary treatments: CON, PB250, PB750, PB1000 and PB1500, with 7 replicates of 11 hens, for 12 weeks. Performance responses were recorded weekly, while ovarian and liver tissues were sampled at the 6 th and 12 th experimental weeks and stored properly for subsequent gene expression analysis. Results showed that dietary PB inclusion improved ( P ≤ 0.05) laying rate, egg mass, and FCR compared to the CON treatment, with optimal results evidenced at PB750. The nutrigenomic analysis revealed that PB inclusion ( P ≤ 0.05) downregulated most of the inflammatory response–related genes in the ovary, affecting 83% and 75% of the 12 critical genes analyzed at the 6 th and 12 th experimental weeks, respectively. Similarly, in the liver, PB supplementation consistently reduced ( P ≤ 0.05) the expression of about 58% of the NF-κB pathway genes across both time points. In conclusion, PB supplementation beneficially modulated the ovarian and hepatic inflammatory response, providing mechanistic evidence explaining further the improvements observed in laying performance, with the 750 mg/kg inclusion level showing the most consistent benefits.