Dietary supplementation of natural tannin relieved intestinal injury and oxidative stress in piglets challenged with enterotoxigenic Escherichia coli

This study is to explore the effects of natural tannin (NBT) on intestinal injury in piglets challenged with enterotoxigenic Escherichia coli (ETEC). Thirty-two 7-day-old piglets were divided into four groups: I) control group, piglets were fed a basic diet without challenge; II) ETEC group, piglets were fed a basic diet and challenged with enterotoxigenic E. coli; III) NBT + ETEC group, piglets were fed a basic diet with supplementation of 2 g/kg NBT and challenged with enterotoxigenic E. coli; and IV) ZnO + ETEC group, piglets were fed a basic diet with supplementation of 3 g/kg ZnO and challenged with enterotoxigenic E. coli. Results showed that diarrhoea rate was significantly increased in ETEC group, whereas it was decreased after NBT supplementation (P < 0.05); NBT supplementation significantly increased the average daily gain of ETEC-infected piglets. ETEC group showed damaged intestinal morphology (as indicated by decreased villus height, surface area and increased crypt depth) and barrier function (as indicated by decreased D-xylose content and increased diamine oxidase activity), induced oxidative stress (as indicated by increased myeloperoxidase activity) while supplementation of NBT had an obvious impact on the recovery of intestinal function and alleviated the oxidative damage. Further analysis showed that NBT could decrease the expression of genes related to intestinal injury (matrix metalloproteinase-3), and specifically upregulate the expression of oxidative stress-related genes (nuclear factor erythroid 2-related factor 2 and hypoxia inducible factor-1). Overall, dietary supplementation of NBT relieved intestinal injury and oxidative stress in piglets challenged with ETEC. NBT could be an alternative to ZnO as a feed additive in piglet diet.