The objective of this study was to investigate the role of human milk oligosaccharides, specifically 2′-Fucosyllactose and Lacto-N-neotetraose, in the immunomodulation of the intestinal mucosa in human microbiota-associated rats. Evidence from studies suggests that 2′-FL and LNnT significantly alleviate damage induced by LPS in the intestines, resulting in a notable increase in DAI scores. Furthermore, 2′-FL and LNnT have been shown to enhance the function of the intestinal barrier and improve the immunity of the intestinal mucosa. This beneficial effect is achieved by increasing the mRNA expression of proteins such as MUC2, Claudin-1, Claudin-2, and ZO-1 in the intestinal tract, while simultaneously promoting a decrease in serum D-Lactate and DAO levels. 2′-FL and LNnT may also play a significant role in ameliorating intestinal immune damage. This is accomplished by suppressing the secretion of pro-inflammatory cytokines while simultaneously augmenting the production of anti-inflammatory cytokines. Furthermore, 2′-FL and LNnT are capable of modulating the cellular immune homeostasis of essential immune cells, including CD4⁺/CD8⁺, Th1/Th2, and Th17/Treg. The findings of this study also revealed that human milk oligosaccharides can ameliorate intestinal dysbiosis triggered by LPS. This includes increasing the abundance of Muribaculaceae and Roseburia, decreasing the abundance of Escherichia-Shigella and Alloprevotella. Furthermore, we conducted a more detailed investigation into the levels of major short-chain fatty acids in the feces of rats and found that 2'-FL and LNnT significantly increased the concentrations of acetate, propionate, and butyrate in the feces of LPS-treated rats. In summary, human milk oligosaccharides demonstrate a significant improvement in intestinal mucosal immunity by refining the structure of the intestinal microbiota, enhancing the functions of the intestinal barrier, and coordinating immune responses.

Considering that vitamin deficiency is prevalent in children, the objective of this study was to evaluate the effects of hawthorn and malt as well as their combination with dietary fibers (polydextrose and xylooligosaccharide) on intestinal function in weaned mice deficient in VB₁, VB₂, VB₆ and VA. The results showed that the intestinal motility of vitamin-deficient mice was significantly promoted by high-dose hawthorn + malt alone and in combination with dietary fibers. Vitamin deficiency significantly reduced body mass gain, food intake and feed utilization in rats by 34.29%, 17.78% and 19.24% (P < 0.05), respectively, the ratio of villus height to crypt depth in jejunum and ileum by 37.30% and 36.79% (P < 0.05), and the contents of acetic acid and total short chain fatty acids (SCFA) in feces by 37.63% and 43.87% (P < 0.05), respectively, compared with the normal group. Food intake and body mass gain in vitamin-deficient rats were significantly increased by 7.84% and 14.77% in the high-dose hawthorn + malt group compared with the vitamin deficiency model group (P < 0.05), respectively. Feed utilization rate in the low-dose hawthorn + malt + dietary fiber group was significantly increased by 11.58%. The ratio of jejunal villus height and crypt depth in the high-dose hawthorn + malt and low-dose hawthorn + malt + dietary fiber groups increased significantly by 52.65% and 47.35% (P < 0.05), respectively. The contents of fecal acetic acid and total SCFAs increased by 46.86% and 78.00% in the high-dose hawthorn + malt group (P < 0.05), and by 43.74% and 44.91% in the low-dose hawthorn + malt + dietary fiber group (P < 0.05), respectively. High-dose hawthorn + malt + dietary fiber treatment led to excessive growth of Parabacteroides in the intestinal tract, thus reducing the diversity and balance of the intestinal flora. High-dose hawthorn + malt treatment could regulate the composition of the intestinal flora and increase the abundance of Lactobacillus and Akkermansia in vitamin-deficient rats. In conclusion, high-dose hawthorn + malt treatment can improve the intestinal flora of rats to some extent, and its effect is similar to that of low-dose hawthorn + malt + dietary fibers. Both of them can promote the growth of bacteria producing SCFA, increasing the intestinal content of SCFAs, improve intestinal morphology, and enhance intestinal absorption function in vitamin-deficient rats, thereby promoting the growth and development of vitamin-deficient rats. These results provide a scientific basis for the development of functional foods.

2’-Fucosyllactose (2’-FL) shows the potential to support intestinal health as a natural prebiotic that bridges the gap between infant formula feeding and breastfeeding. However, the effect and mechanism of 2’-FL in improving intestinal permeability are not clear. In this study, we constructed human microbiota-associated (HMA) mouse models by colonizing healthy infant feces in mice with antibiotic-depleted intestinal microbiota. The protective effect of 2’-FL on the intestinal permeability was explored using the HMA mouse models, and the combination of metagenomics was used to analyze the possible mechanisms by which the microorganisms reduced the intestinal permeability. The results showed that 2’-FL decreased the concentration of markers of intestinal permeability (enterotoxin and diamine oxidase (DAO)) and increased the expression levels of tight junctions (occludin and claudin). Metagenomics revealed the enrichment of Bifidobacterium and increased the expression of glycoside hydrolases (GHs), including GH31, GH28, and GH5. In conclusion, 2’-FL strengthened intestinal permeability function by improving microbiota composition to control the translocation of harmful substance.