Butyrate modulates inflammatory cytokines and tight junctions components along the gut of weaned pigs

Butyrate is added to weaning diets to improve performance and gut health. Although the mechanism of action has been extensively studied on cell cultures, in vivo specific data on gut barrier integrity in pigs are currently lacking. The aim of this study was to investigate the expression of inflammation markers and tight junctions (TJ) components along the gut of piglets fed butyrate at weaning. Fifty-six weaned pigs were fed two diets (n = 7): a pre-starter with or without Na-butyrate providing 960 mg/kg of butyric acid (SB). After 21 d, 7 pigs/group were weighed and euthanized to collect intestinal samples for mRNA analysis. Data were analyzed with t-Student. Performance was not affected, but SB increased tumor necrosis factor α (TNF-α) and interferon γ (IFN-γ) in the duodenum (P = 0.01), decreased TNF-α in the ileum (P = 0.001), and reduced TNF-α and IFN-γ in the colon (P = 0.02). Occludin was increased in the duodenum (P = 0.02) and tended to increase in the jejunum (P = 0.07), whereas claudin-1 was reduced in the duodenum, jejunum, and ileum (P < 0.05) and tended to be reduced in the colon (P = 0.07). SB induced a differential response in the upper and lower intestine by up-regulating inflammatory cytokines in the duodenum, probably because of a fast absorption in this tract, and reducing the inflammatory stress in the lower gut. SB gave conflicting results also on TJ: we observed a general up-regulation of occludin mainly in the small intestine and a down-regulation of claudin-1 along the gut, but the reason remains unclear. To conclude our results suggest that Na-butyrate impacts the gut health status differentially in a tract-specific way without affecting growth.