Adaptation of gut microbiome to different dietary nonstarch polysaccharide fractions in a porcine model

Scope: Dietary fibers, consisting of nonstarch polysaccharides (NSPs) were found to modulate the gut microbiota. However, little is known about the role of a separated fiber fraction. Here, we describe a response in gut microbiome to different fiber fractions using a porcine model. Methods and results: Ileal and cecal digesta were collected from pigs fed with fiber-free diet (FFD) or diet containing 5% cellulose (CEL), xylan (XYL) or beta-glucan (GLU). We observed an elevated 16S rRNA gene copies in ileum and cecum digesta after NSP ingestion. Interestingly, we found that cecum digesta contained higher bacterial diversity than ileum digesta. Moreover, NSPs had no significant influence on overall diversity, but acutely altered the abundance of specific bacteria. Importantly, NSPs decreased the abundance of phylum Firmicutes, but increased the phylum Proteobacteria in ileal samples. Among the NSP-treated groups, pigs on CEL-containing diet had exclusively higher abundance of Lactobacillus spp. in the ileum. Whereas, the GLU-treated samples had more Clostridium spp. Conclusion: This study not only indicated how the gut microbiome adapts to the three major NSP fractions, but the results also contribute to our understanding of the role of dietary fibers in modulating gut microbiota and health.