Hepatic cytoprotective and immunomodulatory responses to dietary phytogenic inclusion level in laying hens

This study investigated the inclusion level effects of a phytogenic premix (PP) on critical homeostasis gene components related to detoxification (Aryl hydrocarbon receptor; AhR), antioxidant (Nuclear factor-erythroid 2-related factor 2; Nrf2), and inflammatory (Nuclear factor-kappa B; NF-κB) responses in laying hens’ liver. A total of 385 Hy-Line Brown hens (20-weeks-old) were allocated to 5 dietary treatments with 7 replicates of 11 hens each. Treatments received a corn-soybean meal basal diet with no PP (CON) or inclusion of PP at 500 (P500), 750 (P750), 1000 (P1000) and 1500 mg/kg diet (P1500), respectively. The PP consisted of bioactive compounds derived from ginger, lemon balm, oregano, and thyme (Anco FIT Poultry). Layers had ad libitum access to feed and water throughout the 12-week feeding trial. Liver samples were collected at experimental weeks 8 and 12 (i.e., 28^th and 32^nd week of layers age) and stored deep frozen until gene expression analysis. The nutrigenomic results revealed that at week 8 (layers 28-week-old), PP significantly (P ≤ 0.05) down-regulated all of the AhR (5/5) and most of the NF-κB (10/15) pathway-related genes while up-regulating (4/11) the Nrf2 pathway-related genes assessed. At week 12, (layers 32-week-old) PP inclusion led to consistent beneficial modulation (P ≤ 0.05) of the AhR (4/5), Nrf2 (7/11), and NF-κB (13/15) pathway-related genes assessed in the liver, with P1000 displaying the most significant differences from the control treatment. Overall, the nutrigenomic analysis revealed phytogenic benefits, providing mechanistic evidence for enhanced hepatic function and health, with P1000 displaying the optimal effects.