scholarly journals Subtle Variations in Dietary-Fiber Fine Structure Differentially Influence the Composition and Metabolic Function of Gut Microbiota

mSphere ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Yunus E. Tuncil ◽  
Riya D. Thakkar ◽  
Seda Arioglu-Tuncil ◽  
Bruce R. Hamaker ◽  
Stephen R. Lindemann

ABSTRACT The chemical structures of soluble fiber carbohydrates vary from source to source due to numerous possible linkage configurations among monomers. However, it has not been elucidated whether subtle structural variations might impact soluble fiber fermentation by colonic microbiota. In this study, we tested the hypothesis that subtle structural variations in a soluble polysaccharide govern the community structure and metabolic output of fermenting microbiota. We performed in vitro fecal fermentation studies using arabinoxylans (AXs) from different classes of wheat (hard red spring [AXHRS], hard red winter [AXHRW], and spring red winter [AXSRW]) with identical initial microbiota. Carbohydrate analyses revealed that AXSRW was characterized by a significantly shorter backbone and increased branching compared with those of the hard varieties. Amplicon sequencing demonstrated that fermentation of AXSRW resulted in a distinct community structure of significantly higher richness and evenness than those of hard-AX-fermenting cultures. AXSRW favored OTUs within Bacteroides, whereas AXHRW and AXHRS favored Prevotella. Accordingly, metabolic output varied between hard and soft varieties; higher propionate production was observed with AXSRW and higher butyrate and acetate with AXHRW and AXHRS. This study showed that subtle changes in the structure of a dietary fiber may strongly influence the composition and function of colonic microbiota, further suggesting that physiological functions of dietary fibers are highly structure dependent. Thus, studies focusing on interactions among dietary fiber, gut microbiota, and health outcomes should better characterize the structures of the carbohydrates employed. IMPORTANCE Diet, especially with respect to consumption of dietary fibers, is well recognized as one of the most important factors shaping the colonic microbiota composition. Accordingly, many studies have been conducted to explore dietary fiber types that could predictably manipulate the colonic microbiota for improved health. However, the majority of these studies underappreciate the vastness of fiber structures in terms of their microbial utilization and omit detailed carbohydrate structural analysis. In some cases, this causes conflicting results to arise between studies using (theoretically) the same fibers. In this investigation, by performing in vitro fecal fermentation studies using bran arabinoxylans obtained from different classes of wheat, we showed that even subtle changes in the structure of a dietary fiber result in divergent microbial communities and metabolic outputs. This underscores the need for much higher structural resolution in studies investigating interactions of dietary fibers with gut microbiota, both in vitro and in vivo.

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1386
Author(s):  
Zixin Yang ◽  
Ting Huang ◽  
Ping Li ◽  
Jian Ai ◽  
Jiaxin Liu ◽  
...  

The interactions between cell-wall polysaccharides and polyphenols in the gastrointestinal tract have attracted extensive attention. We hypothesized that dietary fiber modulates the fermentation patterns of cyanidin-3-O-glucoside (C3G) in a fiber-type-dependent manner. In the present study, the effects of four dietary fibers (fructose-oligosaccharides, pectin, β-glucan and arabinoxylan) on the modulation of C3G fermentation patterns were investigated through in vitro fermentation inoculated with human feces. The changes in gas volume, pH, total carbohydrate content, metabolites of C3G, antioxidant activity, and microbial community distribution during in vitro fermentation were analyzed. After 24 h of fermentation, the gas volume and total carbohydrate contents of the four dietary-fiber-supplemented groups respectively increased and decreased to varying degrees. The results showed that the C3G metabolites after in vitro fermentation mainly included cyanidin, protocatechuic acid, 2,4,6-trihydroxybenzoic acid, and 2,4,6-trihydroxybenzaldehyde. Supplementation of dietary fibers changed the proportions of C3G metabolites depending on the structures. Dietary fibers increased the production of short-chain fatty acids and the relative abundance of gut microbiota Bifidobacterium and Lactobacillus, thus potentially maintaining colonic health to a certain extent. In conclusion, the used dietary fibers modulate the fermentation patterns of C3G in a fiber-type-dependent manner.


mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
T. M. Cantu-Jungles ◽  
B. R. Hamaker

ABSTRACT Dietary fibers can be utilized to shape the human gut microbiota. However, the outcomes from most dietary fibers currently used as prebiotics are a result of competition between microbes with overlapping abilities to utilize these fibers. Thus, divergent fiber responses are observed across individuals harboring distinct microbial communities. Here, we propose that dietary fibers can be classified hierarchically according to their specificity toward gut microbes. Highly specific fibers harbor chemical and physical characteristics that allow them to be utilized by only a narrow group of bacteria within the gut, reducing competition for that substrate. The use of such fibers as prebiotics targeted to specific microbes would result in predictable shifts independent of the background microbial composition.


2019 ◽  
Vol 57 (1) ◽  
pp. 152-162 ◽  
Author(s):  
Lina Yang ◽  
Yafan Zhao ◽  
Jinghang Huang ◽  
Hongyun Zhang ◽  
Qian Lin ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Tingting Chen ◽  
Daiwen Chen ◽  
Gang Tian ◽  
Ping Zheng ◽  
Xiangbing Mao ◽  
...  

The main purpose of the present study was to assess the effect of soluble and insoluble fiber on colonic bacteria and intestinal barrier function in a piglet model. A total of 24 piglets (25 ± 1 d old; 7.50 ± 0.31 kg) were randomly allotted to 4 treatments: basal diet (control, CON), 1% insoluble dietary fiber (IDF) diet, 1% soluble dietary fiber (SDF) diet, and 0.5% insoluble fiber + 0.5% soluble dietary fiber (MDF) diet. The trial lasted 28 days. SDF-fed piglets showed a higher P<0.05 bacterial a-diversity (observed_species, chao1, and ACE) and a higher relative abundance of Proteobacteria and Actinobacteria, Solobacterium, Succinivibrio, Blautia, and Atopobium in colonic digesta than CON, IDF, and MDF groups P<0.05. At the same time, Bacteroidetes, Euryarchaeota, Phascolarctobacterium, Coprococcus_1, and Prevotella_1 were significantly increased in the IDF group when compared with CON, SDF, and MDF groups P<0.05. Furthermore, Bacteroidetes and Enterobacteriaceae, Selenomonas, Phascolarctobacterium, and AlloprevotellaP<0.05 were significantly higher in the MDF group than those in the other three groups P<0.05. SDF diet increased the concentrations of short-chain fatty acid (SCFA) in colonic digesta P<0.05 when compared with the CON group and enhanced weight index of the colon P<0.05 than the CON and IDF groups. Furthermore, compared with the CON group, SDF, IDF, and MDF diets all upregulated the mRNA expressions of claudin-1 (CLDN-1) in colonic mucosa P<0.05, SDF and IDF diets upregulated the mRNA expressions of mucin 2 (MUC2) P<0.05, SDF diet increased mRNA expressions of zonula occludens 1 (ZO-1) and occludin (OCLN), while the IDF group enhanced the secretory immunoglobulin A (sIgA) concentrations P<0.05, respectively. IDF and MDF diets decreased expressions of TNF-αP<0.05. We concluded that the influence of soluble fiber on colonic microbiota was more extensive than that of insoluble fiber. Moreover, soluble fiber could more effectively improve colonic barrier function by upregulating gene expressions of the gut barrier.


Nutrients ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1495 ◽  
Author(s):  
Aldrine Kilua ◽  
Riri Nomata ◽  
Ryuji Nagata ◽  
Naoki Fukuma ◽  
Kenichiro Shimada ◽  
...  

The prevalence of many chronic diseases which have been associated with poor nutrition may be reduced by the positive modulation of colonic microbiota. In this study, we assess the effects of purple sweet potato polyphenols (PSP) in a mixed culture of swine fecal bacteria during in vitro colonic fermentation using pig colonic digest. Jar fermenters were used to conduct a small scale in vitro colonic fermentation experiments under the anaerobic condition for 48 h. Jar fermenters were assigned to one of the following groups: Cellulose, cellulose + PSP, inulin, and inulin + PSP. The present study revealed that the polyphenolic content of purple sweet potato could modulate the colonic microbiota by differentially increasing the population of beneficial bacteria and decreasing the pathogenic bacteria depending on cellulose and inulin. Accordingly, PSP might be a material conducive for improving the conditions for the fermentation of partly-fermentable dietary fiber. Besides, PSP was also responsible for the drastic reduction of putrefactive products, especially p-cresol to a significant level. Our results suggest that PSP could alter the microbial composition depending upon the fermentability of dietary fiber and has the potential to maintain a stable and healthy colonic environment that will ultimately alleviate chronic diseases development and confer health benefits to the host.


Nutrients ◽  
2017 ◽  
Vol 9 (6) ◽  
pp. 533 ◽  
Author(s):  
Athanasios Koutsos ◽  
Maria Lima ◽  
Lorenza Conterno ◽  
Mattia Gasperotti ◽  
Martina Bianchi ◽  
...  

2015 ◽  
Vol 5 (11) ◽  
pp. 395 ◽  
Author(s):  
Chiraphon Chaikliang ◽  
Santad Wichienchot ◽  
Wirote Youravoug ◽  
Potchanapond Graidist

Background: β-glucan is dietary fiber, a structural polysaccharide, β-linked linear chains of D-glucose polymers with variable frequency of branches. β-glucan is isolated from different sources such as cell walls of baker’s yeast (Saccharomyces cerevisiae), cereals (oat and barley) and various species of mushrooms. Among 8 mushrooms in the study, Schizophylum commune Fr and Auricularia auricula Judae had the highest in β-glucan contents and the cheapest cost of mushroom per content of β-glucan, respectively. Even the function of β-glucan on immune modulation has been known however no report on interaction between β-glucan and human gut microbiota. Gut microbiota is thought to have health effects by interaction with non-digestible component particular fermentable dietary fiber. It is important to correlate the specific groups of the microbial communities associated with β-glucan fermentation and the consequential SCFA profiles. β-glucan from mushroom may has potential prebiotic function similar to those from commercial yeast (Saccharomyces cerevisiae) β-glucan. Objective: To evaluate on prebiotic properties of soluble β-glucans and oligo-β-glucans from Schizophylum commune Fr and Auricularia auricula Judae by fecal fermentation in batch culture. Methods: In vitro fecal fermentation in anaerobic batch cultures under simulated conditions similar to human colon with human faecal samples from three donors were performed. Comparison on 3 β-glucans and 2 oligo-β-glucans have been studied. Sample was taken at 0 h, 24 h and 48 h to analyze the numbers of bacterial changes by fluorescent in situ hybridization (FISH) technique. Short chain fatty acids (SCFA) were analyzed by HPLC. The prebiotic index (PI) was calculated according to the change of 5 specific bacterial genus within 48 h fermentation. Results: Soluble β-glucan from Auricularia auricula Judae increased numbers of bifidobacteria and lactobacillus significantly (P<0.05). The PI of soluble β-glucan and oligo-β-glucan from Schizophylum commune Fr were 0.01 and -0.01, respectively. β-glucan and oligo-β-glucan from Auricularia auricula Judae were 0.11 and -0.07, respectively. Whereas PI of β-glucan from commercial yeast (Saccharomyces cerevisiae) was 0.03. Acetate was the most prevalent SCFA found in all treatments followed by propionate, butyrate and lactate, respectively. Conclusion: The study confirmed that β-glucan from Schizophylum commune Fr and Auricularia auricula Judae are candidate prebiotics. Keywords: β-glucan, oligo-β-glucan, prebiotic, mushroom, fecal batch culture


2021 ◽  
Author(s):  
Kavita Rani ◽  
Jitendra Kumar ◽  
Sonia Sangwan ◽  
Nampher Masharing ◽  
Murli Dhar Mitra ◽  
...  

Food is a basic requirement for human life and well-being. On the other hand, diet is necessary for growth, health and defense, as well as regulating and assisting the symbiotic gut microbial communities that inhabit in the digestive tract, referred to as the gut microbiota. Diet influences the composition of the gut microbiota. The quality and quantity of diet affects their metabolism which creates a link between diet. The microorganisms in response to the type and amount of dietary intake. Dietary fibers, which includes non-digestible carbohydrates (NDCs) are neither neither-digested nor absorbed and are subjected to bacterial fermentation in the gastrointestinal tract resulting in the formation of different metabolites called SCFAs. The SCFAs have been reported to effect metabolic activities at the molecularlevel. Acetate affects the metabolic pathway through the G-protein-coupled receptor (GPCR) and free fatty acid receptor2 (FFAR2/GPR43) while butyrate and propionate transactivate the peroxisome proliferator-activated receptors (PPARγ/NR1C3) and regulate the PPARγ target gene Angptl4 in colonic cells of the gut. The NDCs via gut microbiota dependent pathway regulate glucose homeostasis, gut integrity and hormone by GPCR, NF-kB, and AMPK-dependent processes. In this chapter, we will focus on dietary fibers, which interact directly with gut microbes and lead to the production of metabolites and discuss how dietary fiber impacts gut microbiota ecology, host physiology, and health and molecule mechanism of dietary fiber on signaling pathway that linked to the host health.


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