Background: Resveratrol, a plant phenol, affords protection against inflammation and oxidative stress. The objective of this study was to investigate the effects of dietary resveratrol supplementation during pregnancy and lactation on the antioxidant status of sows and piglets and on antioxidant gene expression and pathway in placenta.Methods: Forty sows were allotted to 2 dietary treatments 20 d after breeding. Sows were fed a control diet and a control diet with 300 mg/kg resveratrol. Oxidative stress biomarkers and antioxidant enzymes were measured in the placenta, milk, and plasma of sows and piglets. Antioxidant gene expression and protein expression of Kelch-like ECH-associated protein 1-Nuclear factor E2-related factor 2(Keap1-Nrf2), nuclear factor kappa B-p65(NFκB-p65) and sirtuin1(Sirt1) were quantified in the placenta.Results: Dietary resveratrol increased the litter and piglets weaning weights. Antioxidant status in the milk, placenta and plasma of sows and piglets was partially improved by dietary resveratrol. In placenta, Nrf2 protein expression was increased and Keap1 protein expression was decreased by dietary resveratrol. The m RNA expression of antioxidant genes including catalase(CAT), glutathione peroxidase 1(GPX1), GPX4, superoxide dismutase 1(SOD1)and heme oxygenase 1(HO1), and phase 2 detoxification genes, including glutamate-cysteine ligase modifier(GCLM), microsomal glutathione S-transferase 1(MGST1) and UDP glucuronosyltransferase family 1 member A1(UGT1 A1), was increased by dietary resveratrol. Dietary resveratrol also increased Sirt1 and phosphorylated NFκB-p65 protein expression in the placenta. We failed to observe any influences of dietary resveratrol on pro-inflammatory cytokine levels, including those of interleukin 1β(IL-1β), IL-6, IL-8 and tumor necrosis factor α(TNF-α). However, we observed that the m RNA expression of IL-8 in placenta was reduced by maternal resveratrol. In addition, dietary resveratrol showed interactive effects with day of lactation on activities of SO