BackgroundIntestinal disorder is an important factor contributing to growth lag and high rates of morbidity and mortality of piglets with intrauterine growth retardation (IUGR). Resveratrol (RSV) and its derivative pterostilbene (PT) are natural stilbenes possessing various bioactivities, such as antioxidative and anti-inflammatory effects. This study compared the protective potential of RSV and PT on the intestinal redox status and gut microbiota in weanling piglets with IUGR.MethodsEighteen male piglets of normal body weight (NBW) and 54 same-sex IUGR piglets were chosen according to their birth and weaning weights. The NBW piglets accepted a basal diet, while the IUGR piglets were allotted to one of three groups according to their body weight at weaning and received a basal diet, an RSV-supplemented diet (300 mg/kg), or a PT-supplemented diet (300 mg/kg), respectively.ResultsCompared with IUGR piglets, both RSV and PT improved the IUGR-associated decrease in jejunal villus height and increases in plasma diamine oxidase activity and D-lactate level and jejunal apoptosis of piglets (P < 0.05). Administering RSV and PT also enhanced jejunal superoxide dismutase activity and the mRNA and protein expression of superoxide dismutase 2 of IUGR piglets by promoting nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation (P < 0.05). Comparatively, PT was more effective than RSV in elevating the villus height/crypt depth ratio and occludin mRNA and protein levels in the jejunum of IUGR piglets (P < 0.05). PT was also superior to RSV in increasing Nrf2 nuclear translocation and inhibiting malondialdehyde accumulation in the jejunum of IUGR piglets (P < 0.05). Additionally, RSV modulated the composition of cecal microbiota of IUGR piglets, as evidenced by increasing the prevalence of the phylum Bacteroidetes and the genera Prevotella, Faecalibacterium, and Parabacteroides and inhibiting the growth of the phylum Proteobacteria and its genera Escherichia and Actinobacillus (P < 0.05). Moreover, RSV significantly increased the butyrate concentration in the cecum of IUGR piglets (P < 0.05).ConclusionPT is more potent than RSV to prevent intestinal oxidative stress, while RSV has a stronger capacity to regulate gut microbiota compared to PT.