A total of 144 Duroc × Landrace ×Yorkshire crossbred weaned piglets at the age of 21 days were assigned to 4 groups with 6 replicates per group and 6 pigs per replicate randomly. Piglets in the control(CTL) group and lipopolysaccharide(LPS) group were fed a basal diet, RE200 and 400 groups were fed a basal diet supplemented with 200 and 400 mg/kg RE, respectively, for 28 days. 100 μg/kg BW LPS was intraperitoneally injected to piglets in the LPS, RE200, and RE400 groups on day 21 and day 28, respectively, and those in CTL group were injected with the same dose of normal saline. The results showed as follows: 1) There were no significant differences in growth performance indexes among all groups(P>0.05). 2) In LPS group, the superoxide dismutase(SOD) content was markedly reduced (P <0.05), the aspartate aminotransferase(AST) and interleukin-6(IL-6) content were markedly elevated(P <0.05) compared to CTL group. In RE200 group, the malondialdehyde(MDA) and AST content was markedly reduced(P <0.05), and the index of total antioxidant capacity(T-AOC) was markedly elevated(P < 0.05) compared to LPS group. In RE400 group, the AST and IL-6 contents were markedly reduced (P < 0.05) compared to LPS group. 3) In LPS group, the villus height and pillow-crypt ratio of ileum were markedly reduced(P <0.01), while the crypt depth was markedly elevated(P <0.01) and diamine oxidase(DAO) content was markedly elevated(P < 0.05) compared to CTL group. In RE200 and RE400 group, the villus height and pillow-crypt ratio of ileum were markedly elevated (P<0.01), while the crypt depth was markedly reduced(P <0.01) compared to LPS group, and DAO content in RE200 group was markedly reduced(P < 0.05) compared to LPS group. 4) The α-diversity analysis indicated no significant variations across all groups(P > 0.05), and the results of β diversity analysis showed that the bacterial community structure was basically similar across all groups. In LPS group, the relative abundances of Romboutsia was markedly elevated(P <0.05) compared to CTL group. In RE200 group, the relative abundances of Romboutsia was markedly reduced(P <0.05), the relative abundance of Lachnospiraceae UCG-004 was markedly elevated(P <0.05) compared to LPS group. In conclusion, dietary adding RE can significantly improve antioxidant capacity, reduce gut permeability, alleviate gut damage, improve gut flora composition of weaned piglets. Under the condition of this experiment, the suitable addition level of RE in the diet of weaned piglets is 200 mg/kg.