The team of Professor Wang Junjun of China Agricultural University revealed the mechanism of xylan alleviating dietary fiber deficiency in pigs

Dietary fiber (DF) is a type of carbohydrate that cannot be degraded by endogenous digestive enzymes but is utilized by microorganisms in the hindgut

First, the authors fed pigs with ileal fistulas on fiber-free diets for 7, 21, and 35 days to study the temporal response of gut microbes to fiber deficiency and found that dietary fiber deficiency can lead to ileal and fecal microbiota Diversity was markedly decreased, with the extinction of Lactobacillus and Bifidobacterium in the ileum and feces, accompanied by a significant decrease in short-chain fatty acids

Based on this result, the author further explored the replenishment effect of different fiber components by adding resistant starch, β-glucan and xylan to the fiber-free diet, and found that among the relevant fiber components, only wood Glycans can significantly alter the microbial population structure and selectively promote the proliferation of Bifidobacterium and Bootella in the porcine hindgut, while resistant starch and β-glucan have no such effect

In order to further verify the regulatory mechanism of xylan, the authors found by metagenomic sequencing that Bifidobacterium pseudominis is the key microorganism to distinguish between the no dietary fiber group and the xylan group, and its abundance is significantly correlated with the concentration of short-chain fatty acids.

Taking the interaction between dietary fiber and gut microbes as an entry point, this study systematically revealed for the first time the negative effects of dietary fiber deficiency on the composition and metabolism of pig gut microbes, and further found that xylan can selectively promote Bifidobacterium pseudominis.