Background:Galacto-oligosaccharides (GOS) have been shown to modulate the intestinal microbiota of suckling piglets to exert beneficial effects on intestinal function. However, the modulation of intestinal microbiota and intestinal function by GOS in intestinal inflammation injury models has rarely been reported. In this study, we investigated the effects of GOS on the colonic mucosal microbiota composition, barrier function and inflammatory response of lipopolysaccharides (LPS)-challenged suckling piglets. Methods:A total of 18 newborn suckling piglets were divided into three groups, the CON group, the LPS-CON group and the LPS-GOS group. Piglets in the LPS-GOS group were orally fed with 1 g/kg body weight of GOS solution every day. On the d 14, piglets in the LPS-CON and LPS-GOS group were challenged intraperitoneally with LPS solution. All piglets were slaughtered 2 h after intraperitoneal injection and sampled. Results:We found that the colonic mucosa of LPS-challenged piglets was significantly injured and shedding, while the colonic mucosa of the LPS-GOS group piglets maintained its structure. Moreover, GOS significantly reduced the concentration of malondialdehyde (MDA) and the activity of reactive oxygen species (ROS) in the LPS-challenged suckling piglets, and significantly increased the activity of total antioxidant capacity (T-AOC). GOS significantly increased the relative abundance of norank_f__Muribaculaceae and Romboutsia, and significantly decreased the relative abundance of Alloprevotella, Campylobacter and Helicobacter in the colonic mucosa of LPS-challenged suckling piglets. In addition, GOS increased the concentrations of acetate, butyrate and total short chain fatty acids (SCFAs) in the colonic digesta of LPS-challenged suckling piglets. GOS significantly reduced the concentrations of interleukin 1β(IL-1β), interleukin 6 (IL-6), tumor necrosis factor-α(TNF-α) and cluster of differentiation 14 (CD14), and the relative mRNA expression of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response 88 (MyD88) in the LPS-challenged suckling piglets. In addition, GOS significantly reduced the relative mRNA expression of mucin2 (MUC2), and significantly increased the protein expression of Claudin-1 and zonula occluden-1 (ZO-1) in LPS-challenged suckling piglets. Conclusions:These results suggested that GOS can modulate the colonic mucosa-associated microbiota composition and improve the intestinal function of LPS-challenged suckling piglets.