Source of gut microbiota determines oat β-glucan degradation and short chain fatty acid-producing pathway

Remolding probiotics for effective treatment of type 2 diabetes via oral administration

Effective, user-friendly, lifestyle-compatible, and economic treatment for type 2 diabetes (T2D) is urgently needed due to its high incidence and health threats. Here, we remolded Lactococcus lactis through genetic engineering to persistently secrete glucagon-like peptide-1 (L. lactis-GLP-1) and subsequent bioorthogonal arming with dopamine (DA)-based "gripper" and β-glucan (GN)-based "shield" (L. lactis-GLP-1-DA@GN) for treatment of T2D mice via oral administration. With protection by GN-based "shield", L. lactis-GLP-1-DA@GN achieved an impressive enhancement of survival by 20666 times compared with bare L. lactis-GLP-1 after experiencing gastrointestinal conditions and DA-based "gripper" was shielded from interaction with the upper digestive tract. Once prebiotic GN was metabolized by gut microbiota into short-chain fatty acids (SCFAs), underlying DA-based "gripper" was exposed to assist intestinal colonization of L. lactis-GLP-1, achieving synergistic treatment effects through secreted GLP-1 and SCFAs. With all advances, oral administration of L. lactis-GLP-1-DA@GN realized effective T2D treatment through improving glucose/lipid homeostasis, repairing major organs' damages, and positively modulating gut microbiota. Moreover, multi-omics analysis revealed that L. lactis-GLP-1-DA@GN also mainly intervened in liver's signaling pathways regarding lipid metabolism and oxidative regulation to advance anti-T2D process. Our strategy marks reconstruction of probiotics by combining chemical and biological tools, broadening the avenue of manipulating probiotics for disease treatments.

Prebiotics empower probiotics with gastrointestinal stress resistance for colon-targeted release to synergistically alleviate colitis

Oral administration of probiotics holds promise for alleviating ulcerative colitis (UC), yet their efficacy is inevitably compromised by the hostile gastrointestinal (GI) environment. Here, we devised a strategy by coating β-glucan (GN) prebiotic onto the surface of Lactobacillus plantarum (Lp) probiotic at the single-cell level (Lp@CGN) based on bioorthogonal chemistry in a layer-by-layer manner. This achieved to form a firm, dense, and multifunctional GN-based "armor" with advances of superior protective properties, colon-targeted degradation, and prebiotic benefits. Under the protection of the prebiotic-based "armor", Lp@CGN exhibited a notable 276-fold increase in the survival rate compared to naïve Lp after exposure to whole GI conditions. Upon reaching the colon, the "armor" was metabolized into short-chain fatty acids (SCFAs) by gut microbiota, facilitating the timely release of Lp within colon, thereby achieving a synergistic treatment effect due to sustained SCFAs generation and Lp liberation. As a result, oral administration of Lp@CGN efficiently realized the alleviation of UC in both preventative and therapeutic models through restoring intestinal mucosal barriers, positively regulating inflammatory cytokines, renovating the dysbiosis of gut microbiota, and promoting SCFAs production. In sum, our strategy marks the reconstruction of probiotics with chemical tools, offering useful insights into powering probiotics for disease treatment.

Functional microbiome assembly in food environments: addressing sustainable development challenges

The global food system faces numerous challenges, creating an urgent need for sustainable reform. Functional microbiome assemblies offer transformative potential by endowing microbial foods with diverse, beneficial characteristics. These assemblies can dynamically influence specific food systems, positioning them as a promising approach for reshaping food production. However, the current applications and types of microbiome assemblies in foods remain limited, with a lack of effective screening and regulatory methods. This review introduces the functions and practical approaches for implementing microbiome assemblies in food systems alongside future directions for enhancing their applications. Several ecological studies evaluated how to regulate functional output and revealed that environmental conditions, which shape the niche for species survival, significantly influenced the functional output of microbiomes. Building on this theoretical foundation, this review presents a model for functional output comprising niche conditions, functional gene codes, and corresponding functional outputs. This model is illustrated with examples to explore sustainable applications and regulatory mechanisms for functional microbiome assemblies. By highlighting the roles of functional outputs in food systems and examining the potential for food environments to induce and modulate microbiome functions, this review provides a roadmap to address emerging challenges in food sustainability.

Process optimization, growth kinetics, and antioxidant activity of germinated buckwheat and amaranth-based yogurt mimic

This study aimed to investigate the integration of cereal and germinated pseudocereals into set-type yogurt mimic, resulting in a novel and nutritious product. Four groups of yogurts mimic, namely CPY-1, CPY-2, CPY-3, and CPY-4, were prepared using different probiotic cultures, including L. acidophilus 21, L. plantarum 14, and L. rhamnosus 296 along with starter cultures. Notably, CPY-2 cultured with L. plantarum and L. rhamnosus and incubated for 12 h exhibited the most desirable attributes. The resulting yogurt demonstrated an acidity of 0.65%, pH of 4.37 and a probiotic count of 6.38 log CFU/mL. The logistic growth model fit revealed maximum growth rates (k, 1/h) and maximum bacterial counts (Nm log CFU/mL) for each CPY variant. The results revealed that CPY-2 significantly improved protein, dietary fiber, phenols and antioxidant capacities compared to the control. Scanning electron microscopy showed more structured and compact casein network in CPY-2, highlighting its superior textural characteristics. Overall, this study demonstrates the incorporation of cereal and germinated pseudocereals into set-type yogurt mimic offers health benefits through increased dietary fiber and β-glucan.

In vitro digestion and fecal fermentation of Tremella fuciformis exopolysaccharides from basidiospore-derived submerged fermentation

Tremella fuciformis polysaccharides (TFPS) belong to natural bioactive macromolecule with both edible and medicinal value, possessing much bioactivities such as anti-tumor, antioxidant, antidiabetics, and immunomodulatory. Currently, the production of TFPS through submerged fermentation (TFPS-1) is gradually replacing the polysaccharides extracted from the fruiting body due to improved fermentation efficiency and reduced separation costs. However, it is still unclear about the effect of TFPS-1 on gastrointestinal digestion and gut microbial fermentation, which is directly related to the function of its biological activity. This study aimed to illustrate the effect of TFPS-1 on digestive process through in vitro digestion and fecal fermentation. TFPS-1 was indigestible during the simulated gastrointestinal tract. But TFPS-1 can be digested by intestinal flora leading to alterations in the total polysaccharides content, molecular weight, and apparent viscosity. Moreover, TFPS-1 regulated the composition of gut microbial, lowering the proportion of Firmicutes to Bacteroidetes and enhancing the abundances of Parabacteroides and Bacteroides. The change of intestinal flora produced more short chain fatty acids and lowered the pH. The KEGG metabolic pathway analysis indicated that TFPS-1 enriched lipid metabolism, glycan biosynthesis and metabolism, and biosynthesis of other secondary metabolites. This study demonstrated that T. fuciformis fermented polysaccharide can be a potential prebiotic to optimize intestinal flora homeostasis and maintain host intestinal health.

In vitro fermentation reveals an interplay relationship between oat β-glucan and human gut Bacteroides and their potential role in regulating gut cytokines

Dietary oat β-glucan regulates the gut microbial composition and structure; however, the interplay relationship between oat β-glucan and the gut microbiota is unclear. In this study, we aim to investigate the interaction between oat β-glucan and human gut Bacteroides, a versatile carbohydrate utilizer, and explore the effect of their interaction on gut immunity homeostasis. The results of in vitro fermentation showed that oat β-glucan significantly increased the abundance of gut Bacteroides at the genus level. Then, Bacteroides strains were isolated from human gut microbiota and 9 strains of Bacteroides could grow on oat β-glucan and degrade oat β-glucan to reducing sugars. Notably, strains Bacteroides xylanisolvens Bac02 and Bacteroides koreensis Bac08 possessed the strongest degradation capacity towards oat β-glucan. Genome analysis and functional annotations suggested that B. xylanisolvens Bac02 and B. koreensis Bac08 contained abundant genes encoding glycoside hydrolases family 3 (GH3) and GH16, which might be responsible for β-glucan degradation. Moreover, cell experiments revealed that the metabolites from oat β-glucan fermentation by these 9 strains of Bacteroides could regulate the polarization of macrophages and maintain gut immunity homeostasis. Our study provides a novel insight into research on the interplay between dietary compounds and the gut microbiota.

Latent Tuberculosis Infection Is Associated with an Enrichment of Short-Chain Fatty Acid-Producing Bacteria in the Stool of Women Living with HIV

Latent tuberculosis infection (LTBI) is common in people living with HIV (PLHIV) in high-TB-burden settings. Active TB is associated with specific stool taxa; however, little is known about the stool microbiota and LTBI in PLHIV. We characterised the stool microbiota of PLHIV with [interferon-γ release assay (IGRA)- and tuberculin skin test (TST)-positive] or without (IGRA- and TST-negative) LTBI (n = 25 per group). The 16S rRNA DNA sequences were analysed using QIIME2, Dirichlet-Multinomial Mixtures, DESeq2, and PICRUSt2. No α- or β-diversity differences occurred by LTBI status; however, LTBI-positive people were Faecalibacterium-, Blautia-, Gemmiger-, and Bacteroides-enriched and Moryella-, Atopobium-, Corynebacterium-, and Streptococcus-depleted. Inferred metagenome data showed that LTBI-negative-enriched pathways included several metabolite degradation pathways. Stool from LTBI-positive people demonstrated differential taxa abundance based on a quantitative response to antigen stimulation. In LTBI-positive people, older people had different β-diversities than younger people, whereas in LTBI-negative people, no differences occurred across age groups. Amongst female PLHIV, those with LTBI were, vs. those without LTBI, Faecalibacterium-, Blautia-, Gemmiger-, and Bacteriodes-enriched, which are producers of short-chain fatty acids. Taxonomic differences amongst people with LTBI occurred according to quantitative response to antigen stimulation and age. These data enhance our understanding of the microbiome's potential role in LTBI.

Latent tuberculosis infection is associated with an enrichment of short chain fatty acid producing bacteria in the stool of women living with HIV

Background

Latent tuberculosis infection (LTBI) is common in people living with HIV (PLHIV) in high TB burden settings. Active TB is associated with specific stool taxa; however, little is known about the stool microbiota and LTBI, including in PLHIV.

Method

Within a parent study that recruited adult females with HIV from Cape Town, South Africa into predefined age categories (18-25, 35-60 years), we characterised the stool microbiota of those with [interferon-γ release assay (IGRA)- and tuberculin skin test (TST)-positive] or without (IGRA- and TST- negative) LTBI (n=25 per group). 16S rRNA DNA sequences were analysed using QIIME2, Dirichlet Multinomial Mixtures, DESeq2 and PICRUSt2.

Results

No α- or β-diversity differences occurred by LTBI status; however, LTBI-positives were Faecalibacterium-, Blautia-, Gemmiger-, Bacteroides-enriched and Moryella-, Atopobium-, Corynebacterium-, Streptococcus-depleted. Inferred metagenome data showed LTBI-negative-enriched pathways included several involved in methylglyoxal degradation, L-arginine, putrescine, 4-aminobutanoate degradation and L-arginine and ornithine degradation. Stool from LTBI-positives demonstrated differential taxa abundance based on a quantitative response to antigen stimulation (Acidaminococcus-enrichment and Megamonas-, Alistipes-, and Paraprevotella-depletion associated with higher IGRA or TST responses, respectively). In LTBI-positives, older people had different β-diversities than younger people whereas, in LTBI-negatives, no differences occurred across age groups.

Conclusion

Amongst female PLHIV, those with LTBI had, vs. those without LTBI, Faecalibacterium, Blautia, Gemmiger, Bacteriodes-enriched, which are producers of short chain fatty acids. Taxonomic differences amongst people with LTBI occurred according to quantitative response to antigen stimulation and age. These data enhance our understanding of the microbiome's potential role in LTBI.

A New Functional Wheat Flour Flatbread (Bazlama) Enriched with High-β-Glucan Hull-Less Barley Flour

Although the Med-Diet is a healthy diet model, it is affected by current dietary habits. Therefore, new foods with improved nutritional value should be developed to respond to the needs of people following the Med-Diet. This study was focused on developing high-β-glucan flat bread (bazlama) with a relatively lower GI. A bread wheat (cv. Tosunbey) flour was enriched with the flour of a high-β-glucan-content hull-less barley (cv. Chifaa) flour (15, 30, 45 and 60%) to develop a functional bazlama. The nutritional and technological properties of bazlama samples enriched with barley flour were compared with the ones produced from bread wheat. All of the barley flour-enriched bazlama samples had higher yellowness values (b*) than the control (both crumb and crust), which is generally preferred by the consumers. Texture results indicated that bazlama samples became harder with the increase in barley flour supplementation level. The results showed that 3 g of β-glucan can be provided from the barley flour-enriched bazlama samples (at 45 and 60% levels), and this is the limit to carry health claims. The bazlama samples enriched with barley flour were richer in Mg, K, Mn, Fe, and Zn minerals than the control (100% Tosunbey flour). While the glycemic index (GI) of commercial bread wheat and Tosunbey bazlama samples were high (88.60% and 79.20%, respectively), GI values of the bazlama samples enriched with 60% (64.73) and 45% barley flour (68.65) were medium. The lower GI values of barley flour-enriched bazlama samples are probably due to the higher β-glucan contents of the bazlama samples. Additionally, as the barley flour supplementation level of the bazlama samples increased, the phenolics and antioxidant capacities of free and bound extracts increased compared to bread wheat bazlama. The results indicated that hull-less barley (cv. Chifaa) with high β-glucan content may be utilized at relatively higher levels (45 and 60%) to produce bazlama with improved nutritional properties.

Modified Prebiotic-Based "Shield" Armed Probiotics with Enhanced Resistance of Gastrointestinal Stresses and Prolonged Intestinal Retention for Synergistic Alleviation of Colitis

Oral administration of probiotics is a promising method to alleviate inflammatory bowel diseases (IBDs). However, gastrointestinal environmental sensitivity and inferior intestinal colonization of probiotics hinder the alleviation effect. Here, we developed a simple yet effective modified prebiotic-based "shield" (Fe-TA@mGN) composed of an Fe3+-tannic acid cross-linking network and carboxymethylated β-glucan for arming Escherichia coli Nissle 1917 (EcN@Fe-TA@mGN). The Fe-TA@mGN "shield" not only acted as a dynamic barrier to enhance the gastrointestinal stress resistance ability of EcN but also aided the intestinal colonization of EcN as well as synergized with EcN for the alleviation of dextran sulfate sodium (DSS) induced colitis. More specifically, with the protection of the Fe-TA@mGN "shield", the survival rate of armed EcN could be up to ∼1720 times higher than that of bare EcN after exposure to simulated gastric fluid. Excitingly, the intestinal retention rate of EcN@Fe-TA@mGN was as high as 47.54 ± 6.06% at 16 h post-administration, while almost all bare EcNs were excreted out at 8 h post-administration. With all of the aforementioned attributes, EcN@Fe-TA@mGN efficiently alleviated colitis, verified by the repair of the intestinal barrier and the attenuation of inflammation. Moreover, for EcN@Fe-TA@mGN, mGN synergized with EcN to positively modulate gut microbiota and promote the production of short-chain fatty acids (SCFAs, especially for butyric acid, a primary source for maintaining intestinal health), both of which would further advance the alleviation of colitis. We envision that the strategy developed here will inspire the exploitation of various prebiotics to arm probiotics for the effective alleviation of IBD.

Interaction of beta-glucans with gut microbiota: Dietary origins, structures, degradation, metabolism, and beneficial function

Beta-glucan (BG), a polysaccharide comprised of interfacing glucose monomers joined via beta-glycosidic linkages, can be defined as a type of dietary fiber with high specificity based on its interaction with the gut microbiota. It can induce similar interindividual microbiota responses, thereby having beneficial effects on the human body. In this paper, we review the four main sources of BG (cereals, fungi, algae, and bacteria) and their differences in structure and content. The interaction of BG with gut microbiota and the resulting health effects have been highlighted, including immune enhancement, regulation of serum cholesterol and insulin levels, alleviation of obesity and improvement of cognitive disorders. Finally, the application of BG in food products and its beneficial effects on the gut microbiota of consumers were discussed. Although some of the mechanisms of action remain unclear, revealing the beneficial functions of BG from the perspective of gut microbiota can help provide theoretical support for the development of diets that target the regulation of microbiota.

β-Glucan alleviates mice with ulcerative colitis through interactions between gut microbes and amino acids metabolism

BACKGROUND

Food polysaccharide 1,3-β-d-glucan (OBG) has been shown to alleviate ulcerative colitis (UC) in a mouse model, but the underlying mechanisms remain unclear. Here, we aimed to investigate potential mechanisms involving interactions among gut microbiota, microbial metabolites and host metabolic function.

RESULTS

OBG alleviated colonic inflammation, barrier dysfunction and intestinal concentrations of short-chain fatty acids in mice with UC. In addition, the relative abundance of Muribaculaceae, Alistipes, Erysipelatoclostridium and Blautia increased, whereas the abundance of Proteus, Lachnospiraceae and Ruminococcus decreased within the gut microbiota upon OBG treatment. Kyoto Encyclopedia of Genes and Genomes analyses showed that intestinal enzymes altered upon OBG treatment were mainly enriched in sub-pathways of amino acid biosynthesis. Metabolomics analyses showed that l-tryptophan, l-tyrosine, l-phenylalanine and l-alanine increased, which is consistent with the predictive metabolism of gut microbiota. Correlation analysis and interaction networks highlighted gut microbiota (especially Lactobacillus, Parabacteroides, Proteus and Blautia), metabolites (especially l-phenylalanine, l-tryptophan, l-tyrosine and acetic acid) and metabolism (phenylalanine, tyrosine and tryptophan biosynthesis) that may be key targets of OBG.

CONCLUSION

OBG is beneficial to the gut microecological balance in mice with colitis, mainly becaue of its impact on the interactions between gut microbes and amino acids metabolism (especially tyrosine and tryptophan metabolism). © 2022 Society of Chemical Industry.

Applicable Strains, Processing Techniques and Health Benefits of Fermented Oat Beverages: A Review

Based on the high nutrients of oat and the demand of health-conscious consumers for value-added and functional foods, fermented oat beverages have great market prospects. This review summarizes the applicable strains, processing techniques and health benefits of fermented oat beverages. Firstly, the fermentation characteristics and conditions of the applicable strains are systematically described. Secondly, the advantages of pre-treatment processes such as enzymatic hydrolysis, germination, milling and drying are summarized. Furthermore, fermented oat beverages can increase the nutrient content and reduce the content of anti-nutritional factors, thereby reducing some risk factors related to many diseases such as diabetes, high cholesterol and high blood pressure. This paper discusses the current research status of fermented oat beverages, which has academic significance for researchers interested in the application potential of oat. Future studies on fermenting oat beverages can focus on the development of special compound fermentation agents and the richness of their taste.

Interaction between β-glucans and gut microbiota: a comprehensive review

Gut microbiota (GMB) in humans plays a crucial role in health and diseases. Diet can regulate the composition and function of GMB which are associated with different human diseases. Dietary fibers can induce different health benefits through stimulation of beneficial GMB. β-glucans (BGs) as dietary fibers have gained much interest due to their various functional properties. They can have therapeutic roles on gut health based on modulation of GMB, intestinal fermentation, production of different metabolites, and so on. There is an increasing interest in food industries in commercial application of BG as a bioactive substance into food formulations. The aim of this review is considering the metabolizing of BGs by GMB, effects of BGs on the variation of GMB population, influence of BGs on the gut infections, prebiotic effects of BGs in the gut, in vivo and in vitro fermentation of BGs and effects of processing on BG fermentability.

Perspectives in the Application of High, Medium, and Low Molecular Weight Oat β-d-Glucans in Dietary Nutrition and Food Technology-A Short Overview

For centuries human civilization has cultivated oats, and now they are consumed in various forms of food, from instant breakfasts to beverages. They are a nutrient-rich food containing linear mixed-linkage (1 → 3) (1 → 4)-β-d-glucans, which are relatively well soluble in water and responsible for various biological effects: the regulation of the blood cholesterol level, as well as being anti-inflammatory, prebiotic, antioxidant, and tumor-preventing. Numerous studies, especially in the last two decades, highlight the differences in the biological properties of the oat β-d-glucan fractions of low, medium, and high molecular weight. These fractions differ in their features due to variations in bioavailability related to the rheological properties of these polysaccharides, and their association with food matrices, purity, and mode of preparation or modification. There is strong evidence that, under different conditions, the molecular weight may determine the potency of oat-extracted β-d-glucans. In this review, we intend to give a concise overview of the properties and studies of the biological activities of oat β-d-glucan preparations depending on their molecular weight and how they represent a prospective ingredient of functional food with the potential to prevent or modulate various pathological conditions.

Salecan confers anti-inflammatory effects in liver injury via regulating gut microbiota and its metabolites

Salecan, a natural β-glucan and one of the novel food ingredients approved in China, has been shown a variety of positive health effects, yet the mechanism of liver injury remains poorly understood. In addition, β-glucan could induce the shifts in gut microbiota, however, whether modulation of gut microbiota by β-glucan is associated with their positive health effects remain elusive. Here, the anti-inflammatory effects and the underlying mechanism of Salecan supplementation in CCl4-induced liver injury were investigated. After 8 weeks of treatment, we observed that Salecan alleviated liver injury by regulating inflammatory response and M2 macrophage polarization. In addition, Salecan treatment modulated the composition of gut microbiota and antibiotic cocktail treatment indicated that the hepatoprotective effect of Salecan was dependent on the gut microbiota. Fecal microbiota transplantation was used to further verify the mechanism, and we confirmed that microbial colonization partially alleviated liver injury. Besides, microbiota-derived metabolites of Salecan also contributed to the hepatoprotective and anti-inflammatory effect of Salecan against liver injury. These findings supported that Salecan intervention attenuated liver injury by regulating gut microbiota and its metabolites.

Effects of Fermented Bamboo Shoot Processing Waste on Growth Performance, Serum Parameters, and Gut Microbiota of Weaned Piglets

Gut microbiota (GM) plays a vital role in the nutrition and metabolism of weaned piglets. Some feed additives can be used to adjust the composition of GM to improve the health of weaned piglets. In this study, we investigated the effects of adding fermented bamboo shoot processing waste (FBSPW) to diet on growth performance, serum parameters, and GM of weaned piglets. Seventy-two piglets were divided into four groups and were fed diets containing 0% (control), 4% (group A), 8% (group B), and 12% (group C) FBSPW for 50 days. We found that the addition of FBSPW significantly decreased the average daily feed intake, serum triglyceride content, and urea nitrogen of weaned piglets compared to the control. The cecum and cecal microbiota of weaned piglets fed the basal diet with 12% FBSPW were significantly different compared to the control. A basal diet with 12% FBSPW significantly reduced the taxon feature number, and the relative abundance of Tenericutes in the cecum and cecal microbiota of weaned piglets compared with the control. The addition of 12% FBSPW to weaned piglet feed could improve their nitrogen and lipid metabolisms and have beneficial effects on GM.

Enzymes-Assisted Extraction of Plants for Sustainable and Functional Applications

The scientific community and industrial companies have discovered significant enzyme applications to plant material. This rise imparts to changing consumers' demands while searching for 'clean label' food products, boosting the immune system, uprising resistance to bacterial and fungal diseases, and climate change challenges. First, enzymes were used for enhancing production yield with mild and not hazardous applications. However, enzyme specificity, activity, plant origin and characteristics, ratio, and extraction conditions differ depending on the goal. As a result, researchers have gained interest in enzymes' ability to cleave specific bonds of macroelements and release bioactive compounds by enhancing value and creating novel derivatives in plant extracts. The extract is enriched with reducing sugars, phenolic content, and peptides by disrupting lignocellulose and releasing compounds from the cell wall and cytosolic. Nonetheless, depolymerizing carbohydrates and using specific enzymes form and release various saccharides lengths. The latest studies show that oligosaccharides released and formed by enzymes have a high potential to be slowly digestible starches (SDS) and possibly be labeled as prebiotics. Additionally, they excel in new technological, organoleptic, and physicochemical properties. Released novel derivatives and phenolic compounds have a significant role in human and animal health and gut-microbiota interactions, affecting many metabolic pathways. The latest studies have contributed to enzyme-modified extracts and products used for functional, fermented products development and sustainable processes: in particular, nanocellulose, nanocrystals, nanoparticles green synthesis with drug delivery, wound healing, and antimicrobial properties. Even so, enzymes' incorporation into processes has limitations and is regulated by national and international levels.

Salecan ameliorates liver injury by regulating gut microbiota and its metabolites

Salecan ameliorates liver injury by regulating oxidative stress and the gut microbiota.

Oat β-glucan alleviates DSS-induced colitis via regulating gut microbiota metabolism in mice

Ulcerative colitis (UC) is one of the most prevalent inflammatory bowel diseases (IBD) worldwide, while oat β-glucan has been shown to suppress the progress of colitis in UC mice. However, the underlying mechanism of oat β-glucan in ameliorating colitis is unclear and the role of gut microbiota in the protective effect of oat β-glucan against colitis remains unknown. In the present study, we aim to investigate the effect of oat β-glucan on gut microbiota in colitis mice and explore the health effect related mechanism. Dextran sulfate sodium (DSS) was used to induce the colitis model in mice. The results showed that β-glucan treatment attenuated hematochezia, splenomegaly and colon shortening in colitis mice. Histological evaluation of H&E and TUNEL staining showed that β-glucan treatment suppressed DSS-induced colonic inflammatory infiltration and reduced cell apoptosis levels of colon tissues. mRNA expression levels of the pro-inflammatory factors were also significantly reduced in the β-glucan group. Moreover, β-glucan treatment increased the protein and mRNA expression levels of tight junction proteins. Analysis of gut microbiota community showed that β-glucan treatment modulated gut microbial composition and structure at the OTU level in colitis mice. Further analysis of gut microbial metabolism revealed that β-glucan treatment significantly increased acetate, propionate and butyrate concentrations, and affected microbial metabolome in colitis mice. Notably, the increased acetate and propionate concentrations could directly affect pro-inflammatory factor expression levels and tight junction protein levels. In contrast, the changes in metabolic profiles affected pro-inflammatory factor levels and thus affected tight junction protein levels. Overall, our study revealed that oat β-glucan ameliorated DSS-induced colitis in mice simultaneously through regulating gut-derived short-chain fatty acids (SCFAs) and microbial metabolic biomarkers. Our study demonstrated that oat β-glucan could be an effective nutritional intervention strategy towards targeting gut microbiota metabolism for ameliorating colitis.

Improvement of Metabolic Syndrome in High-Fat Diet-Induced Mice by Yeast β-Glucan Is Linked to Inhibited Proliferation of Lactobacillus and Lactococcus in Gut Microbiota

There is growing evidence that prevention of metabolic syndrome (MS) by dietary fibers is intricately linked to gut microbiota. In the present work, the mice were fed a high-fat diet (HFD) and orally treated with yeast β-glucan to further examine the effects of β-glucan on MS and gut microbiota and the potential relationship between gut microbiota and its activity. After intervention for 10 weeks, it was found that the treatment of yeast β-glucan could significantly improve the HFD-induced MS. Furthermore, pro-inflammatory cytokines in plasma including IL-6 and IL-1β were decreased. Yeast β-glucan could regulate the diversity and composition of HFD-induced gut microbiota. Moreover, the relative abundances of Lactobacillus and Lactococcus, having significant positive correlation with metabolic changes, were decreased by β-glucan, which might play a critical role in attenuation of MS. Our findings suggest that yeast β-glucan shows promising application as a prebiotic for preventing MS and regulating gut microbiota.