Background:This study evaluated the use of dietary vitamin E and polyphenols on growth, immune and oxidative status of weaned pigs fed peroxidized lipids. A total of 192 piglets (21 days of age and body weight of 6.62 ± 1.04 kg) were assigned within sex and weight blocks to a 2 × 3 factorial arrangement using 48 pens with 4 pigs perpen. Dietary treatments consisted of lipid peroxidation (6％edible soybean oil or 6％peroxidized soybean oil), and antioxidant supplementation (control diet containing 33 IU/kg DL-α-tocopheryl-acetate;control with 200 IU/kg additional dl-α-tocopheryl-acetate;or control with 400 mg/kg polyphenols). Pigs were fed in 2 phases for 14 and 21 days, respectively. Results:Peroxidation of oil for 12 days at 80 °C with exposure to 50 L/min of air substantially increased peroxide values, anisidine value, hexanal, and 2,4-decadienal concentrations. Feeding peroxidized lipids decreased (P<0.001) body weight (23.16 vs. 18.74 kg), daily gain (473 vs. 346 g/d), daily feed intake (658 vs. 535 g/d) and gain:feed ratio (719 vs. 647 g/kg). Lipid peroxidation decreased serum vitamin E (P<0.001) and this decrease was larger on day 35 (1.82 vs. 0.81 mg/kg) than day 14 (1.95 vs. 1.38 mg/kg). Supplemental vitamin E, but not polyphenols, increased (P≤0.002) serum vitamin E by 84％and 22％for control and peroxidized diets, respectively (interaction, P=0.001). Serum malondialdehyde decreased (P<0.001) with peroxidation on day 14, but not day 35 and protein carbonyl increased (P<0.001) with peroxidation on day 35, but not day 14. Serum 8-hydroxydeoxyguanosine was not affected (P>0.05). Total antioxidant capacity decreased with peroxidation (P<0.001) and increased with vitamin E (P=0.065) and polyphenols (P=0.046) for the control oil diet only. Serum cytokine concentrations increased with feeding peroxidized lipids on day 35, but were not affected by antioxidant supplementation (P>0.05). Conclusion:Feeding peroxidized lipids negatively impacted growth performance and antioxidant capacity of nursery pigs. Supplementation of vitamin E and polyphenols improved total antioxidant capacity, especially in pigs fed control diets, but did not restore growth performance.