Fructooligosaccharides improves growth performance and intestinal epithelium function in weaned pigs exposure to Enterotoxigenic Escherichia coli
This study was conducted to explore the protective potential of Fructooligosaccharides (FOS) against Enterotoxigenic Escherichia coli (ETEC)-induced inflammation and intestinal injury in weaned pigs. Twenty-four weaned pigs were randomly assigned into three groups: (1) non-challenge (CON), (2) ETEC-challenge (ECON), and (3) ETEC challenge + 250 mg/kg FOS (EFOS). On day 19, non-challenged pigs were orally infused with sterilized culture while pigs in other groups were orally infused with ETEC (2.5 × 1010 colony-forming units). After 3 days, pigs were slaughtered for sample collection. We showed that ETEC-challenged significantly reduced average daily gain (ADG); however, FOS improved the ADG (P<0.05) and apparent digestibility of crude protein (CP), gross energy (GE), and ash in the ETEC-challenged pigs (P<0.05). FOS reduced plasma concentrations of IL-1β and TNF-α, and elevated the concentrations of immunoglobulin A (IgA) and immunoglobulin M (IgM) (P<0.05). Interestingly, FOS elevated villus height in duodenum, and elevated the ratio of villus height to crypt depth in the duodenum and ileum in the ETEC-challenged pigs (P<0.05). Moreover, FOS increased lactase activity in the duodenum and ileum (P<0.05). The activities of sucrase and alkaline phosphatase (AKP) were higher in EFOS group than in the ECON group (P<0.05). Importantly, FOS up-regulated the expressions of critical genes in intestinal epithelium function such as zonula occludens-1 (ZO-1), L-type amino acid transporter-1 (LAT1), and cationic amino acid transporter-1 (CAT1) in the duodenum and the expressions of ZO-1 and glucose transporter-2 (GLUT2) in the jejunum (P<0.05). FOS also up-regulated the expressions of occludin, fatty acid transporter-4 (FATP4), sodium glucose transport protein 1 (SGLT1), and GLUT2 in the ileum (P<0.05). FOS significantly increased the concentrations of acetic acid, propionic acid and butyric acid in the cecal digesta. Additionally, FOS reduced the populations of Escherichia coli, but elevated the populations of Bacillus and Bifidobacterium in the caecal digesta (P<0.05). These results suggested that FOS can improve the growth performance and intestinal health in weaned pigs upon ETEC challenge, which was associated with suppressed inflammatory responses and improved intestinal epithelium functions and microbiota.