Dietary Zanthoxylum bungeanum leaf powder improves growth performance and antioxidant capacity via Nrf2/HO-1 signaling pathway in broilers

This study focused on the effects of dietary Zanthoxylum bungeanum leaves (ZBL) powder on the growth performance and antioxidant capacity via the Nrf2/HO-1 signaling pathway in broilers. The experiment adopted a single-factor completely random design, and 440 healthy one-day-old AA broiler chicks were randomly divided into four groups: the control group (CON) was fed a corn-soybean meal-based diet, the CZ1 group was fed a basic diet with 1% ZBL powder, the CZ2 group fed a basic diet with 2% ZBL powder, and the CZ3 group fed a basic diet with 3% ZBL powder. The experiment was divided into the starter period (1-21 d) and the grower period (22-42 d). There were five replicates per group in the starter period, with 22 chickens per replicate. The same grouping as in the starter period was used in the grower period, with 20 chickens per replicate. The results showed that the addition of ZBL powder to the diet had no adverse effects on the growth performance and morphological structure of the intestine of broiler chickens in the CZ1 and CZ2 groups (P > 0.05). Compared with the control group, the diet with 1% and 2% ZBL powder significantly increased the antioxidant indicators such as CAT, T-AOC, and T-SOD in the serum and liver tissue of broiler chickens, it upregulated the related genes expression of nuclear factor erythroid derived-2/heme oxygenase-1 (Nrf2/HO-1) signaling pathway such as Nrf2, NQO1, HO-1, SOD1, and CAT in the jejunal mucosa and enhanced the expression of ZO-1 and OCLN genes in the jejunal mucosa (P < 0.05). In conclusion, dietary supplementation with 1% and 2% of ZBL powder into the daily diet can enhance the body's antioxidant capacity by elevating antioxidant levels in both serum and liver, upregulates the expression of genes associated with the Nrf2/HO-1 signaling pathway in the jejunal mucosa, and helps maintain the integrity of the intestinal mucosal barrier. The optimal addition level of ZBL powder in the diet was determined by quadratic regression analysis to be 1.36%-1.60% during days 1-21 and 1.14%-1.50% during days 22-42.