Abstract
Human gut bacteria contribute significantly to human health and several studies have evaluated the effects of dietary fibers on human gut bacterial ecology. However, the relationship between different degrees of fiber polymerization and human gut bacteria is unknown. Here, we analyzed three fiber substrates with different degrees of polymerization, namely carboxymethylcellulose, β-glucans, and galactooligosaccharides. To probe the in vitro influence of the degree of polymerization of the fiber on human gut bacteria, we measured the pH, air pressure, and short-chain fatty acid content of fecal fermentation supplemented with these fiber substrates, and sequenced the 16S ribosomal RNA genes of the microbial community in the fiber-treated fermentations. The butyric acid concentration was shown to decline with decreasing degree of polymerization of the fiber. Illumina Miseq sequencing indicated that the degree of polymerization might have an influence on human gut microbial diversity and abundance. Principal coordinate analysis unveiled a relationship between the degree of fiber polymerization and the gut bacterial community. Specific microbiota operational taxonomic units (OTUs) within the genera Escherichia-Shigella, Fusobacterium, and Dorea were proportional to the degree of fiber significantly, whereas OTUs within the genera Bifidobacterium, Streptococcus, and Lactobacillus were inversely correlated with the degree of polymerization. Correlation analysis between the fiber degree of polymerization and gut bacteria may demonstrate the effect of fibers on gut microbiota, and subsequently, on human health.
Highlights
The human gut bacterial population is host-specific, constantly changing throughout an individual’s lifetime and prone to influence or harm by both exogenous and endogenous modification (Sekirov et al, 2010)
All of the sequences were clustered into Operational Taxonomic Units (OTUs) based on a 97% identity threshold by the SILVA database (Quast et al, 2013)
This study investigate the effect of fibers supplementation with different degree of polymerization (DP) value on in vitro growth of undefined bacterial communities representing the human gut microbiota
Summary
The human gut bacterial population is host-specific, constantly changing throughout an individual’s lifetime and prone to influence or harm by both exogenous and endogenous modification (Sekirov et al, 2010). Human gut bacteria evolve over time with changes in diet and overall health (Hooda et al, 2012). Recent food science research has demonstrated that dietary fiber has an influence on human gut bacterial ecology. The microbial ecosystem can be disrupted by low-fiber diets, causing chronic inflammation, which leads to the eradication of essential microbial taxa. The average total dietary fiber intake in Chinese adults is far below the Fibers Influence Human Gut Bacteria recommended daily intake, which can lead to chronic metabolic conditions (Wang et al, 2014), such as type 2 diabetes, cardiovascular disease, and obesity (Kaoutari et al, 2013; Gentile and Weir, 2018; Sanna et al, 2019). The degree of polymerization (DP) impacts the physicochemical properties and physiological effects of fiber type. The influence of DP on human gut bacteria warrants assessment (Verspreet et al, 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
