The bifidogenic effect of inulin and oligofructose and its consequences for gut health

Microbiome composition and presence of cultivable commensal groups of Southern Tamanduas (Tamandua tetradactyla) varies with captive conditions

Southern Tamanduas (Tamandua tetradactyla) belong to the specialized placental myrmecophages. There is not much information about their intestinal microbiome. Moreover, due to their food specialization, it is difficult to create an adequate diet under breeding conditions. Therefore, we used 16S rDNA amplicon sequencing to analyze the fecal microbiome of captive Southern Tamanduas from four locations in the Czech Republic and evaluated the impact of the incoming diet and facility conditions on microbiome composition. Together with the microbiome analysis, we also quantified and identified cultivable commensals. The anteater fecal microbiome was dominated by the phyla Bacillota and Bacteroidota, while Pseudomonadota, Spirochaetota, and Actinobacteriota were less abundant. At the taxonomic family level, Lachnospiraceae, Prevotellaceae, Bacteroidaceae, Oscillospiraceae, Erysipelotrichaceae, Spirochaetaceae, Ruminococcaceae, Leuconostocaceae, and Streptococcaceae were mainly represented in the fecal microbiome of animals from all locations. Interestingly, Lactobacillaceae dominated in the location with a zoo-made diet. These animals also had significantly lower diversity of gut microbiome in comparison with animals from other locations fed mainly with a complete commercial diet. Moreover, captive conditions of analyzed anteater included other factors such as the enrichment of the diet with insect-based products, probiotic interventions, the presence of other animals in the exposure, which can potentially affect the composition of the microbiome and cultivable microbes. In total, 63 bacterial species from beneficial commensal to opportunistic pathogen were isolated and identified using MALDI-TOF MS in the set of more than one thousand selected isolates. Half of the detected species were present in the fecal microbiota of most animals, the rest varied across animals and locations.

Gastric Cancer, Immunotherapy, and Nutrition: The Role of Microbiota

Immune checkpoint inhibitors (ICI) have revolutionized the treatment of gastric cancer (GC), which still represents the third leading cause of cancer-related death in Western countries. However, ICI treatment outcomes vary between individuals and need to be optimized. Recent studies have shown that gut microbiota could represent a key influencer of immunotherapy responses. At the same time, the nutritional status and diet of GC patients are also predictive of immunotherapy treatment response and survival outcomes. The objective of this narrative review is to gather recent findings about the complex relationships between the oral, gastric, and gut bacterial communities, dietary factors/nutritional parameters, and immunotherapy responses. Perigastric/gut microbiota compositions/functions and their metabolites could be predictive of response to immunotherapy in GC patients and even overall survival. At the same time, the strong influence of diet on the composition of the microbiota could have consequences on immunotherapy responses through the impact of muscle mass in GC patients during immunotherapy. Future studies are needed to define more precisely the dietary factors, such as adequate daily intake of prebiotics, that could counteract the dysbiosis of the GC microbiota and the impaired nutritional status, improving the clinical outcomes of GC patients during immunotherapy.

Inulin: Unveiling its potential as a multifaceted biopolymer in prebiotics, drug delivery, and therapeutics

In recent years, inulin has gained much attention as a promising multifunctional natural biopolymer with numerous applications in drug delivery, prebiotics, and therapeutics. It reveals a multifaceted biopolymer with transformative implications by elucidating the intricate interplay between inulin and the host, microbiome, and therapeutic agents. Their flexible structure, exceptional targetability, biocompatibility, inherent ability to control release behavior, tunable degradation kinetics, and protective ability make them outstanding carriers in healthcare and biomedicine. USFDA has approved Inulin as a nutritional dietary supplement for infants. The possible applications of inulin in biomedicine research inspired by nature are presented. The therapeutic potential of inulin goes beyond its role in prebiotics and drug delivery. Recently, significant research efforts have been made towards inulin's anti-inflammatory, antioxidant, and immunomodulatory properties for their potential applications in treating various chronic diseases. Moreover, its ability to reduce inflammation and modulate immune responses opens new avenues for treating conditions such as autoimmune disorders and gastrointestinal ailments. This review will attempt to illustrate the inulin's numerous and interconnected roles, shedding light on its critical contributions to the advancement of healthcare and biomedicine and its recent advancement in therapeutics, and conclude by taking valuable insights into the prospects and opportunities of inulin.

Methods to mitigate Escherichia coli blooms in human ex vivo colon model experiments using the high throughput micro-Matrix bioreactor fermentation system

Ex vivo colon model experiments are frequently employed as a means to assess the gut microbiome modulating potential of different foods, food ingredients and dietary supplements. A number of useful models already exist; however, they tend to be relatively low in terms of throughput (3-4 samples per experiment) with a long experiment duration of one to a number of weeks. Therefore, a need for a high-throughput system with a short duration time is required to enable screening of large numbers of samples. Therefore, we report here on the development of a system based on the Applikon micro-Matrix bioreactor which has the capacity to run 24 samples with an experiment duration of 48 h. However, Escherichia coli blooms are a common problem encountered in this model. Here, we describe the factors that contribute to such blooms and provide approaches to address them, providing:•Step by step optimisation of processes involved in conducting ex vivo distal colon experiments using the micro-Matrix bioreactor fermentation platform•Recommended steps for users on how to attenuate E. coli blooms in such ex vivo colon model experiments.

Consumption of yacon flour and energy-restricted diet increased the relative abundance of intestinal bacteria in obese adults

Prebiotics can alter the gastrointestinal environment, favoring the growth of health-promoting bacteria. Although yacon is a functional food, with prebiotic properties (fructooligosaccharides), its effects on the intestinal microbiota have not been investigated yet. The objective of this study was to evaluate the effects of yacon flour consumption and energy-restricted diet in the intestinal microbiota in adults with excess body weight. Twenty-one adults with excess body weight were included in this randomized, parallel, double-blind, placebo-controlled, 6-week clinical trial. Subjects daily consumed at breakfast a drink containing 25 g of yacon flour (n = 11) or not containing yacon (n = 10) and received the prescription of energy-restricted diets. Fecal samples were collected on the first and on last day of the study. 16S rRNA sequencing was assessed to evaluate the effect of yacon fermentation on intestinal microbiota bacterial composition. There was an increase in the genera Bifidobacterium, Blautia, Subdoligranulum, and Streptococcus after the consumption of yacon and energy-restricted diet. In the yacon group, we also observed a positive correlation between the concentrations of short-chain fatty acids versus the genera Coprococcus and Howardella, besides a negative correlation between the concentrations of advanced glycation end products and early glycation products versus the genera Ruminococcus and Prevotella, respectively. Consumption of yacon flour and energy-restricted diet selectively changed the intestinal microbiota composition in adults with excess body weight. TRIAL REGISTRATION: Register number: RBR-6YH6BQ. Registered 23 January, 2018.

Refined fiber inulin promotes inflammation-associated colon tumorigenesis by modulating microbial succinate production

BACKGROUND AND AIM

There is an increased risk of colon cancer associated with inflammatory bowel disease (IBD). Dietary fibers (DFs) naturally present in vegetables and whole grains offer numerous beneficial effects on intestinal health. However, the effects of refined DFs on intestinal health remain unclear. Therefore, we elucidated the impact of the refined DF inulin on colonic inflammation and tumorigenesis.

METHODS

Four-week-old wild-type (WT) mice were fed diets containing insoluble DF cellulose (control) or refined DF inulin for 4 weeks. A subgroup of mice was then switched to drinking water containing dextran sulfate sodium (DSS, 1.4% wt/vol) for colitis induction. In another subgroup of mice, colitis-associated colorectal cancer (CRC) was initiated with three 7-day alternate cycles of DSS following an initial dose of mutagenic substance azoxymethane (AOM; 7.5 mg/kg body weight; i.p.). Post 7 weeks of AOM treatment, mice were euthanized and examined for CRC development.

RESULTS

Mice consuming inulin-containing diet exhibited severe colitis upon DSS administration, as evidenced by more body weight loss, rectal bleeding, and increased colonic inflammation than the DSS-treated control group. Correspondingly, histological analysis revealed extensive disruption of colon architecture and massive infiltration of immune cells in the inulin-fed group. We next examined the effect of inulin on CRC development. Surprisingly, significant mortality (~50%) was observed in the inulin-fed but not in the control group during the DSS cycle. Consequently, the remaining inulin-fed mice, which completed the study exhibited extensive colon tumorigenesis. Immunohistochemical characterization showed comparatively high expression of the cell proliferation marker Ki67 and activation of the Wnt signaling in tumor sections obtained from the inulin-fed group. Gut microbiota and metabolite analysis revealed expansion of succinate producers and elevated cecal succinate in inulin-fed mice. Human colorectal carcinoma cells (HCT116) proliferated more rapidly when supplemented with succinate in an inflamed environment, suggesting that elevated luminal succinate may contribute to tumorigenesis.

CONCLUSIONS

Our study uncovers that supplementation of diet with refined inulin induces abnormal succinate accumulation in the intestinal lumen, which in part contributes to promoting colon inflammation and tumorigenesis.

In vitro fermentation assay on the bifidogenic effect of steviol glycosides of Stevia rebaudiana plant for the development of dietetic novel products

The relationship between excessive sugar consumption and many diseases such as dental caries, obesity, diabetes and coronary heart has been increasing in recent years. In this study, utilization of natural sugar replacer steviol glycosides and bifidogenic effect by Bifidobacterium animalis subsp. lactis was assayed in vitro model system. The basal medium (non-carbohydrate containing MRS, Man, Rogosa and Sharpe Agar) were supplemented with 0.025% and 1% stevia, 0.025% stevia + 1% inulin, %1 stevia + 1% inulin. The medium which contained no carbohydrate was designated as negative control, whereas the medium containing 1% glucose or inulin were evaluated as positive and evaluated on the 0, 12, 24, 36 and 48 h of fermentation. Steviol glycosides in both system significantly stimulated the growth of Bifidobacterium animalis subsp. lactis to varying degrees with highest prebiotic activity score, short chain fatty acid production and growth parameters as much as glucose and prebiotic inulin. The viability of the probiotic bacteria was determined within the bio-therapeutic level with potential prebiotic effects depending on the probiotic bacterial strain growing and the type of carbohydrate source utilized. In the study, stevia at lower concentration showed a higher growth rate of with inulin. In conclusion, stevia can be used as functional ingredients for the modulation of the gut microbiota and design of synbiotic systems as a prebiotic substrate and sugar substitute.

Inulin Attenuates Blood-Brain Barrier Permeability and Alleviates Behavioral Disorders by Modulating the TLR4/MyD88/NF-κB Pathway in Mice with Chronic Stress

Depression and vulnerability to chronic stress are associated with inflammatory responses and the loss of blood-brain barrier (BBB) integrity. Dietary fiber and its short-chain fatty acid (SCFAs) metabolites have been reported to affect neuropsychiatric disorders. Here, a 9-week treatment course of inulin (0.037 g of inulin/kcal) exhibited in chronic unpredictable mild stress (CUMS) mice led to antidepressant and anxiolytic effects, as well as improved neurogenesis and synaptic plasticity by enhancing CREB/BDNF signaling. Importantly, inulin inhibited CUMS-induced decreased BBB permeability, reduced lipopolysaccharide (LPS) brain penetration, and modulated TLR4/MyD88/NF-κB signaling to alleviate neuroinflammatory responses. Furthermore, inulin protected the gut barrier integrity and led to the increased formation of SCFAs. Enhanced SCFAs formation was strongly positively correlated with behavioral improvements, BBB integrity, and neuroinflammatory responses. We speculate that dietary fiber may be a promising nutritional intervention to reverse the effects of chronic stress by regulating metabolites and protecting the BBB integrity.

The Effect of Probiotic Bacteria on Composition and Metabolite Production of Faecal Microbiota Using In Vitro Batch Cultures

Probiotic supplements are increasingly being used to target the gut microbiome with a view to improving cognitive and psychological function via the gut-brain axis. One possible mechanism behind the effect of probiotics is through alterations to microbially-derived metabolites including short-chain fatty acids (SCFA) and neurotransmitters. However, research to date has largely been conducted in animal models or under conditions irrelevant to the human gastrointestinal tract (GIT). The aim of the current work was therefore to use anaerobic, pH controlled in vitro batch cultures to (a) assess the production of neuroactive metabolites in human faecal microbiota under conditions relevant to the human GIT, and (b) to explore how several pre-selected probiotic strains may affect bacterial composition and metabolite production. Enumeration of bacteria was assessed using fluorescence in situ hybridisation with flow cytometry, and concentrations of SCFAs and neurotransmitters were measured using gas chromatography and liquid chromatography mass spectroscopy, respectively. GABA, serotonin, tryptophan, and dopamine were successfully detected, suggesting some level of microbial derivation. The addition of Lactococcus lactis W58 and Lactobacillus rhamnosus W198 resulted in a significant increase in lactate after 8 h of fermentation, while no significant effect of probiotics on bacterial composition or neurotransmitter production was found.

Therapeutic and Preventive Effect of Orally Administered Prebiotics on Atopic Dermatitis in a Mouse Model

PURPOSE

Recently, interest is increasing in using prebiotics, which are nutrient ingredients of live microorganism that improve the intestinal environments by promoting the growth of beneficial gut microflora. Although numerous studies have demonstrated the beneficial effects of probiotics on atopic dermatitis (AD) development, few have examined preventive and therapeutic effects of prebiotics on the onset and progression of AD.

METHODS

In this study, we investigated therapeutic and preventive effect of prebiotics, including β-glucan and inulin, using an oxazolone (OX)-induced AD-like mouse model. Prebiotics were orally administered 2 weeks after the end of sensitization period (therapeutic study) and 3 weeks before the initial sensitization (prevention study). The physiological and histological alterations in the skin and gut of the mice were investigated.

RESULTS

In the therapeutic study, the severity of skin lesions and inflammatory responses were effectively reduced after administering β-glucan and inulin, respectively. The expression level of calprotectin was significantly decreased by approximately 2-fold (P < 0.05) in the skin and gut of prebiotics-treated mice compared to the control. In addition, epidermal thickness and the number of infiltrated immune cells were markedly reduced in the dermis of prebiotics-treated mice compared <strike>with</strike> to those in the OX-induced mice (P < 0.05). These findings were same as in the prevention study. Importantly, pre-administration of β-glucan and inulin prevented the progression of AD by promoting the growth of good bacteria in the gut of OX-induced AD mice. However, the co-administration of β-glucan and inulin did not show enhanced preventive effects on these alterations.

CONCLUSIONS

Prebiotics has a therapeutic effect on AD in OX-induced AD mouse model. Moreover, our study suggests that prebiotics prevents the development of AD and this effect is associated with a change in gut microbiome.

A major mechanism for immunomodulation: Dietary fibres and acid metabolites

Diet and the gut microbiota have a profound influence on physiology and health, however, mechanisms are still emerging. Here we outline several pathways that gut microbiota products, particularly short-chain fatty acids (SCFAs), use to maintain gut and immune homeostasis. Dietary fibre is fermented by the gut microbiota in the colon, and large quantities of SCFAs such as acetate, propionate, and butyrate are produced. Dietary fibre and SCFAs enhance epithelial integrity and thereby limit systemic endotoxemia. Moreover, SCFAs inhibit histone deacetylases (HDAC), and thereby affect gene transcription. SCFAs also bind to 'metabolite-sensing' G-protein coupled receptors (GPCRs) such as GPR43, which promotes immune homeostasis. The enormous amounts of SCFAs produced in the colon are sufficient to lower pH, which affects the function of proton sensors such as GPR65 expressed on the gut epithelium and immune cells. GPR65 is an anti-inflammatory Gα_s-coupled receptor, which leads to the inhibition of inflammatory cytokines. The importance of GPR65 in inflammatory diseases is underscored by genetics associated with the missense variant I231L (rs3742704), which is associated with human inflammatory bowel disease, atopic dermatitis, and asthma. There is enormous scope to manipulate these pathways using specialized diets that release very high amounts of specific SCFAs in the gut, and we believe that therapies that rely on chemically modified foods is a promising approach. Such an approach includes high SCFA-producing diets, which we have shown to decrease numerous inflammatory western diseases in mouse models. These diets operate at many levels - increased gut integrity, changes to the gut microbiome, and promotion of immune homeostasis, which represents a new and highly promising way to prevent or treat human disease.

Comparative analysis of prebiotic effects of four oligosaccharides using in vitro gut model: digestibility, microbiome, and metabolome changes

Fructooligosaccharides (FOS), Ad-fructooligosaccharides (Ad-FOS), resistant maltodextrin (RMD), and maltooligosaccharides (MOS) are commercially available prebiotic oligosaccharides. In this study, the effects of prebiotics on the human gut microbial ecosystem were evaluated using an in vitro gut model. FOS and Ad-FOS showed tolerance to digestion, whereas RMD and MOS showed moderate digestion by digestive enzymes. In in vitro fecal fermentation, Bifidobacterium spp. increased in the following order: FOS, Ad-FOS, MOS, and RMD, whereas Bacteroides spp. increased in RMD medium. Bacteroides xylanisolvens exhibited cross-feeding by enabling the growth of other beneficial bacteria during co-culture in RMD medium. In metabolome analysis, total short-chain fatty acids (SCFAs) were highly produced in the following order: RMD, FOS, MOS, and Ad-FOS; acetate in the order of FOS, MOS/RMD, and Ad-FOS; butyrate in the order of RMD, MOS, FOS, and Ad-FOS; and propionate only in RMD. In addition, the conversion of betaine to trimethylamine was rarely affected in the following order: MOS, RMD, FOS, and Ad-FOS. Lastly, the four oligosaccharides inhibited the adhesion of pathogenic Escherichia coli to human epithelial cells to a similar extent. The comparative analysis results obtained in this study will provide comprehensive information of these substances to manufacturers and customers.

Inulin prebiotic reinforces host cancer immunosurveillance via ɣδ T cell activation

The gut microbiota is now recognized as a key parameter affecting the host's anti-cancer immunosurveillance and ability to respond to immunotherapy. Therefore, optimal modulation for preventive and therapeutic purposes is very appealing. Diet is one of the most potent modulators of microbiota, and thus nutritional intervention could be exploited to improve host anti-cancer immunity. Here, we show that an inulin-enriched diet, a prebiotic known to promote immunostimulatory bacteria, triggers an enhanced Th1-polarized CD4⁺ and CD8⁺ αβ T cell-mediated anti-tumor response and attenuates tumor growth in three preclinical tumor-bearing mouse models. We highlighted that the inulin-mediated anti-tumor effect relies on the activation of both intestinal and tumor-infiltrating ɣδ T cells that are indispensable for αβ T cell activation and subsequent tumor growth control, in a microbiota-dependent manner. Overall, our data identified these cells as a critical immune subset, mandatory for inulin-mediated anti-tumor immunity in vivo, further supporting and rationalizing the use of such prebiotic approaches, as well as the development of immunotherapies targeting ɣδ T cells in cancer prevention and immunotherapy.

Functional response to a microbial synbiotic in the gastrointestinal system of children: a randomized clinical trial

BACKGROUND

Oral microbial therapy has been studied as an intervention for a range of gastrointestinal disorders. Though research suggests that microbial exposure may affect the gastrointestinal system, motility, and host immunity in a pediatric population, data have been inconsistent, with most prior studies being in neither a randomized nor placebo-controlled setting. The aim of this randomized, placebo-controlled study was to evaluate the efficacy of a synbiotic on increasing weekly bowel movements (WBMs) in constipated children.

METHODS

Sixty-four children (3-17 years of age) were randomized to receive a synbiotic (n = 33) comprising mixed-chain length oligosaccharides and nine microbial strains, or placebo (n = 31) for 84 days. Stool microbiota was analyzed on samples collected at baseline and completion. The primary outcome was a change from baseline of WBMs in the treatment group compared to placebo.

RESULTS

Treatment increased (p < 0.05) the number of WBMs in children with low baseline WBMs, despite broadly distinctive baseline microbiome signatures. Sequencing revealed that low baseline microbial richness in the treatment group significantly anticipated improvements in constipation (p = 0.00074).

CONCLUSIONS

These findings suggest the potential for (i) multi-species-synbiotic interventions to improve digestive health in a pediatric population and (ii) bioinformatics-based methods to predict response to microbial interventions in children.

IMPACT

Synbiotic microbial treatment improved the number of spontaneous weekly bowel movements in children compared to placebo. Intervention induced an increased abundance of bifidobacteria in children, compared to placebo. All administered probiotic species were enriched in the gut microbiome of the intervention group compared to placebo. Baseline microbial richness demonstrated potential as a predictive biomarker for response to intervention.

Crosstalk between traditional Chinese medicine-derived polysaccharides and the gut microbiota: A new perspective to understand traditional Chinese medicine

Polysaccharide is a kind of macromolecule polymer composed of monosaccharides connected by glycosidic bonds. Traditional Chinese medicine (TCM), composed of various bioactive ingredients, is usually rich in polysaccharides. In recent years, extensive research on TCM polysaccharides has demonstrated their pharmacological effects. Polysaccharides can hardly be catabolized by enzymes encoded by the human genome but can be degraded to absorbable metabolites by bacteria inhabiting the colon. Hence, the gut microbiota plays a vital role in degrading TCM polysaccharides into short-chain fatty acids (SCFAs) which exert physiological functions locally and systemically. Besides, TCM polysaccharides can also modulate the composition and activities of the gut microbiota by promoting the growth of beneficial bacteria and inhibiting the colonization of pathogenic bacteria, ultimately restoring gut homeostasis and improving human health. In this review, we discuss the extraction and pharmacological effects of TCM polysaccharides, various functions of the gut microbiota, and the interactions between TCM polysaccharides and the gut microbiota, illuminating the mechanisms of TCM polysaccharides modulating host physiology via the gut microbiota. To firmly establish the clinical efficacy of TCM polysaccharides, further high-quality studies especially clinical trials are needed. Generally, discussion on the interplay between TCM polysaccharides and the gut microbiota is expected to elucidate their application prospects and inspire new thoughts in the development of TCM.

Effects of inulin supplementation on inflammatory biomarkers and clinical symptoms of women with obesity and depression on a calorie-restricted diet: a randomised controlled clinical trial

Major depressive disorder (MDD) is regarded as an inflammatory disorder. Gut microbiota dysbiosis, observed in both MDD and obesity, leads to endotoxemia and inflammatory status, eventually exacerbating depressive symptoms. Manipulation of gut microbiota by prebiotics might help alleviate depression. The present study aimed to investigate the effects of inulin supplementation on psychological outcomes and biomarkers of gut permeability, endotoxemia, inflammation, and brain-derived neurotrophic factor (BDNF) in women with obesity and depression on a calorie-restricted diet. In a double-blind randomised clinical trial, forty-five women with obesity and MDD were allocated to receive 10 g/d of either inulin or maltodextrin for 8 weeks; all the patients followed a healthy calorie restricted diet as well. Anthropometric measures, dietary intakes, depression, and serum levels of zonulin, lipopolysaccharide (LPS), inflammatory biomarkers (TNF-α, IL-10, monocyte chemoattractant protein-1, toll-like receptor-4 and high-sensitivity C-reactive protein), and BDNF were assessed at baseline and end of the study. Weight and Hamilton Depression Rating Scale (HDRS) scores decreased in both groups; between-group differences were non-significant by the end of study (P = 0·333 for body weight and P = 0·500 for HDRS). No between-group differences were observed for the other psychological outcomes and serum biomarkers (P > 0·05). In this short-term study, prebiotic supplementation had no significant beneficial effects on depressive symptoms, gut permeability, or inflammatory biomarkers in women with obesity and depression.

Modulating Microbiota as a New Strategy for Breast Cancer Prevention and Treatment

Breast cancer (BC) is the most common cancer in women in the United States. There has been an increasing incidence and decreasing mortality rate of BC cases over the past several decades. Many risk factors are associated with BC, such as diet, aging, personal and family history, obesity, and some environmental factors. Recent studies have shown that healthy individuals and BC patients have different microbiota composition, indicating that microbiome is a new risk factor for BC. Gut and breast microbiota alterations are associated with BC prognosis. This review will evaluate altered microbiota populations in gut, breast tissue, and milk of BC patients, as well as mechanisms of interactions between microbiota modulation and BC. Probiotics and prebiotics are commercially available dietary supplements to alleviate side-effects of cancer therapies. They also shape the population of human gut microbiome. This review evaluates novel means of modulating microbiota by nutritional treatment with probiotics and prebiotics as emerging and promising strategies for prevention and treatment of BC. The mechanistic role of probiotic and prebiotics partially depend on alterations in estrogen metabolism, systematic immune regulation, and epigenetics regulation.

Assessment of the bifidogenic and antibacterial activities of xylooligosaccharide

Xylooligosaccharide (XOS) is an attractive prebiotic mainly due to its bifidogenic effect. However, commercial XOS with different compositions is often applied in the food industry at different doses without specifications. In this study, we evaluated the bifidogenic activity of XOS at different doses with either mixtures or pure fractions with different degrees of polymerization (DP), using three strains of Bifidobacterium spp., including B. breve ATCC 15700, B. bifidum ATCC 29521, and B. animalis subsp. lactis HN019. Three growth indicators showed strain-specific bifidogenic activity of XOS, and the activity was both dose- and fraction-dependent as only certain fractions stimulated significant growth. Adding 0.25% XOS (w/v) also promoted increase in total bifidobacterial population of rat fecal samples fermented in vitro. Albeit the antibacterial activity of XOS fractions can be demonstrated, significant growth inhibition can only be achieved when 4.0% XOS mixture was added in Staphylococcus aureus ATCC 6538 pure culture. In contrast, in the presence of B. lactis HN019, 1.0% XOS showed significant antibacterial activity against S. aureus ATCC 6538 in milk. In addition, RNA sequencing suggested downregulation of genes involved in S. aureus ATCC 6538 infection, pathogenesis, and quorum sensing, by XOS. In conclusion, the report urges scientific specifications on XOS chemistry for its effective application as a novel food ingredient or functional food and provides novel insights into its bifidogenic and antibacterial activities.

Gut microbiota dysbiosis: The potential mechanisms by which alcohol disrupts gut and brain functions

Alcohol use disorder (AUD) is a high-risk psychiatric disorder and a key cause of death and disability in individuals. In the development of AUD, there is a connection known as the microbiota-gut-brain axis, where alcohol use disrupts the gut barrier, resulting in changes in intestinal permeability as well as the gut microbiota composition, which in turn impairs brain function and worsens the patient’s mental status and gut activity. Potential mechanisms are explored by which alcohol alters gut and brain function through the effects of the gut microbiota and their metabolites on immune and inflammatory pathways. Alcohol and microbiota dysregulation regulating neurotransmitter release, including DA, 5-HT, and GABA, are also discussed. Thus, based on the above discussion, it is possible to speculate on the gut microbiota as an underlying target for the treatment of diseases associated with alcohol addiction. This review will focus more on how alcohol and gut microbiota affect the structure and function of the gut and brain, specific changes in the composition of the gut microbiota, and some measures to mitigate the changes caused by alcohol exposure. This leads to a potential intervention for alcohol addiction through fecal microbiota transplantation, which could normalize the disruption of gut microbiota after AUD.

Temporal Dynamics of the Intestinal Microbiome Following Short-Term Dietary Restriction

Short-term dietary restriction has been proposed as an intriguing pre-operative conditioning strategy designed to attenuate the surgical stress response and improve outcomes. However, it is unclear how this nutritional intervention influences the microbiome, which is known to modulate the systemic condition. Healthy individuals were recruited to participate in a four-day, 70% protein-restricted, 30% calorie-restricted diet, and stool samples were collected at baseline, after the restricted diet, and after resuming normal food intake. Taxonomy and functional pathway analysis was performed via shotgun metagenomic sequencing, prevalence filtering, and differential abundance analysis. High prevalence species were altered by the dietary intervention but quickly returned to baseline after restarting a regular diet. Composition and functional changes after the restricted diet included the decreased relative abundance of commensal bacteria and a catabolic phenotype. Notable species changes included Faecalibacterium prausnitzii and Roseburia intestinalis, which are major butyrate producers within the colon and are characteristically decreased in many disease states. The macronutrient components of the diet might have influenced these changes. We conclude that short-term dietary restriction modulates the ecology of the gut microbiome, with this modulation being characterized by a relative dysbiosis.

Multi-Omic Analyses Reveal Bifidogenic Effect and Metabolomic Shifts in Healthy Human Cohort Supplemented With a Prebiotic Dietary Fiber Blend

Dietary fiber, a nutrient derived mainly from whole grains, vegetables, fruits, and legumes, is known to confer a number of health benefits, yet most Americans consume less than half of the daily recommended amount. Convenience and affordability are key factors determining the ability of individuals to incorporate fiber-rich foods into their diet, and many Americans struggle to access, afford, and prepare foods rich in fiber. The objective of this clinical study was to test the changes in microbial community composition, human metabolomics, and general health markers of a convenient, easy to use prebiotic supplement in generally healthy young participants consuming a diet low in fiber. Twenty healthy adults participated in this randomized, placebo-controlled, double-blind, crossover study which was registered at clinicaltrials.gov as NCT03785860. During the study participants consumed 12 g of a prebiotic fiber supplement and 12 g of placebo daily as a powder mixed with water as part of their habitual diet in randomized order for 4 weeks, with a 4-week washout between treatment arms. Fecal microbial DNA was extracted and sequenced by shallow shotgun sequencing on an Illumina NovaSeq. Plasma metabolites were detected using liquid chromatography–mass spectrometry with untargeted analysis. The phylum Actinobacteria, genus Bifidobacterium, and several Bifidobacterium species (B. bifidum, B. adolescentis, B. breve, B. catenulatum, and B. longum) significantly increased after prebiotic supplementation when compared to the placebo. The abundance of genes associated with the utilization of the prebiotic fiber ingredients (sacA, xfp, xpk) and the production of acetate (poxB, ackA) significantly changed with prebiotic supplementation. Additionally, the abundance of genes associated with the prebiotic utilization (xfp, xpk), acetate production (ackA), and choline to betaine oxidation (gbsB) were significantly correlated with changes in the abundance of the genus Bifidobacterium in the prebiotic group. Plasma concentrations of the bacterially produced metabolite indolepropionate significantly increased. The results of this study demonstrate that an easy to consume, low dose (12 g) of a prebiotic powder taken daily increases the abundance of beneficial bifidobacteria and the production of health-promoting bacteria-derived metabolites in healthy individuals with a habitual low-fiber diet.

Influence of infection with Brachyspira hyodysenteriae on clinical expression, growth performance, and digestibility in growing pigs fed diets varying in type and level of fiber

Research on the effects of different fiber types and levels on infection with Brachyspira hyodysenteriae on growth performance and nutrients digestibility in pigs is scarce. The objective of the current study was to investigate the effects of infection with B. hyodysenteriae when feeding diets varying in soluble and insoluble dietary fiber (DF) on the expression of swine dysentery, growth performance, and digestibility of organic matter (OM) nutrients. A total of 96 growing pigs (26.9 ± 2.5 kg) were used for the experiment and divided into six blocks. The growing pigs were fed one of four diets for 12 wk: low fiber (LF), high fiber (HF), high soluble fiber (HS), and high insoluble fiber (HI). After 2 wk, half of the pigs were inoculated with B. hyodysenteriae. Half of the pigs in each group were euthanized at week 6 for the measurement of the apparent digestibility at the ileum, cecum, colon, and total tract. The remaining pigs were maintained to observe and analyze the clinical expression of fecal score and excretion of B. hyodysenteriae, growth performance, and total tract digestibility up to 12 wk. In the current study, the experimental diets did not influence the expression of infection in the pigs. The body weight and average daily gain (ADG) were in line with the results of clinical expression from week 4 to 6. However, the ADG of the infected pigs started to recover from week 6 (P < 0.05) and then recovered from week 8 to 12 (P < 0.05). The infection with B. hyodysenteriae did not impair apparent ileal digestibility (AID; P > 0.05), whereas the apparent digestibility of OM, total non-starch polysaccharide, non-cellulosic polysaccharide, and cellulose in the cecum of the infected pigs was higher than non-infected pigs (P < 0.05). The apparent colonic digestibility of ash and nitrogen was higher in non-infected pigs than in infected pigs (P < 0.05). The pigs fed the LF diet had a higher digestibility in all segments of the intestinal tract, whereas the HS diet had the lowest AID but higher or similar to the LF diet in the cecum, colon, and the total tract (P < 0.05). The pigs fed the HF and HI diets, with a high proportion of insoluble fiber, had a lower digestibility in the hindgut than the other two diets (P < 0.05). In conclusion, the infection with B. hyodysenteriae negatively influenced clinical signs of swine dysentery and growth performance but did not impair AID, and neither soluble nor insoluble DF influenced the expression of the infection.

Assessment of the Effects of the Synbiotic Combination of Bifidobacterium longum subsp. infantis CECT 7210 and Oligofructose-Enriched Inulin Against Digestive Bacterial Infections in a Piglet Model

The use of bifidobacteria as probiotics has proven to be beneficial in gastroenteric infections. Furthermore, prebiotics such as inulin can enhance the survival and growth of these bacteria. Two trials were performed to evaluate the effects of the administration of Bifidobacterium longum subsp. infantis CECT 7210 and oligofructose-enriched inulin against Salmonella enterica serovar Typhimurium or enterotoxigenic Escherichia coli (ETEC) F4. A total of 72 (Salmonella trial) and 96 (ETEC F4 trial) weaned piglets were used in a 2 × 2 design (with or without synbiotic, inoculated or not with the pathogen). After adaptation, animals were orally inoculated. Performance and clinical signs were evaluated. On days 4 and 8 (Salmonella trial) and 3 and 7 (ETEC F4 trial) post-inoculation (PI), one animal per pen was euthanized. Blood, digestive content and tissue samples were collected and microbiological counts, fermentation products, serum inflammatory markers and ileum histomorphometry analysis were performed. Both challenges had an impact on faecal consistency (p < 0.001), including the faecal shedding of Salmonella and increased numbers of enterobacteria and coliforms. The synbiotic administration did not have any effect on pathogen loads but induced changes in the fermentation profile, such as increased valeric acid in both trials as well as decreased acetic acid, except for Salmonella-challenged animals. The effect on propionate varied among trials, increasing in challenged synbiotic-treated pigs and decreasing in non-challenged ones in the Salmonella trial (P interaction = 0.013), while the opposed occurred in the ETEC F4 trial (P interaction = 0.013). The administration of the synbiotic increased intraepithelial lymphocytes (IEL; p = 0.039) on day 8 PI in the Salmonella trial and a similar trend occurred in non-challenged pigs in the ETEC F4 trial (P interaction = 0.086). The results did not provide evidence of reduced pathogen load with the synbiotic, although a modulation in fermentative activity could be identified depending on the challenge. Consistent increases were found in IEL, suggesting that this synbiotic combination has some immunomodulatory properties.

Synthetic glycans control gut microbiome structure and mitigate colitis in mice

Relative abundances of bacterial species in the gut microbiome have been linked to many diseases. Species of gut bacteria are ecologically differentiated by their abilities to metabolize different glycans, making glycan delivery a powerful way to alter the microbiome to promote health. Here, we study the properties and therapeutic potential of chemically diverse synthetic glycans (SGs). Fermentation of SGs by gut microbiome cultures results in compound-specific shifts in taxonomic and metabolite profiles not observed with reference glycans, including prebiotics. Model enteric pathogens grow poorly on most SGs, potentially increasing their safety for at-risk populations. SGs increase survival, reduce weight loss, and improve clinical scores in mouse models of colitis. Synthetic glycans are thus a promising modality to improve health through selective changes to the gut microbiome.

Recent development in fabrication and evaluation of phenolic-dietary fiber composites for potential treatment of colonic diseases

Phenolics have been shown by in vitro and animal studies to have multiple pharmacological effects against various colonic diseases. However, their efficacy against colonic diseases, such as inflammatory bowel diseases, Crohn's disease, and colorectal cancer, is significantly compromised due to their chemical instability and susceptibility to modification along the gastrointestinal tract (GIT) before reaching the colonic site. Dietary fibers are promising candidates that can form phenolic-dietary fiber composites (PDC) to carry phenolics to the colon, as they are natural polysaccharides that are non-digestible in the upper intestinal tract but can be partially or fully degradable by gut microbiota in the colon, triggering the release at this targeted site. In addition, soluble and fermentable dietary fibers confer additional health benefits as prebiotics when used in the PDC fabrication, and the possibility of synergistic relationship between phenolics and fibers in alleviating the disease conditions. The functionalities of PDC need to be characterized in terms of their particle characteristics, molecular interactions, release profiles in simulated digestion and colonic fermentation to fully understand the metabolic fate and health benefits. This review examines recent advancements regarding the approaches for fabrication, characterization, and evaluation of PDC in in vitro conditions.

Modulation of Gut Microbiota and Immune System by Probiotics, Pre-biotics, and Post-biotics

The human gastrointestinal tract harbours a complex microbial community, which interacts with the mucosal immune system closely. Gut microbiota plays a significant role in maintaining host health, which could supply various nutrients, regulate energy balance, modulate the immune response, and defence against pathogens. Therefore, maintaining a favourable equilibrium of gut microbiota through modulating bacteria composition, diversity, and their activity is beneficial to host health. Several studies have shown that probiotics and pre-biotics could directly and indirectly regulate microbiota and immune response. In addition, post-biotics, such as the bioactive metabolites, produced by gut microbiota, and/or cell-wall components released by probiotics, also have been shown to inhibit pathogen growth, maintain microbiota balance, and regulate an immune response. This review summarises the studies concerning the impact of probiotics, pre-biotics, and post-biotics on gut microbiota and immune systems and also describes the underlying mechanisms of beneficial effects of these substances. Finally, the future and challenges of probiotics, pre-biotics, and post-biotics are proposed.

Inulin as a functional ingredient and their applications in meat products

Inulin, a fructan-type non-digestible carbohydrate, is a natural functional dietary fiber found in selected plants including chicory, garlic, onion, leeks and asparagus. Due to increasing popularity of inulin and rising awareness toward its low calorie value and prebiotic related health implications, consumers are becoming more conscious on consuming inulin incorporated foods. In this review, the scientific studies published in recent years regarding potential applications of inulin in meat products; and their effects on physicochemical and sensory properties, and health implications are discussed. Meat based functional foods with inulin can lead to enhance digestive health by reducing the risk of diseases like constipation, irritable bowel syndrome, inflammatory bowel disease and colorectal cancer. Inulin can be an interesting prebiotic ingredient in healthier meat formulations, apart from being a fat replacer and dietary fiber enhancer.

Fructooligosaccharides on inflammation, immunomodulation, oxidative stress, and gut immune response: a systematic review

CONTEXT

Evidence shows that fructooligosaccharides (FOSs) can modulate inflammatory, oxidative, and immune activity in the gut, possibly leading to a systemic response, improving human health.

OBJECTIVE

To assess the present knowledge of the effects of FOSs on inflammation, immunomodulation, oxidative stress, and gut immune response.

DATA SOURCES

Studies published between December 2000 and January 2020 were systematically searched in four databases: MEDLINE, LILACS, Web of Science, and Scopus. After the screening of 1316 articles, 8 human studies and 20 animal models were included.

DATA EXTRACTION

Data were extracted separately by 2 reviewers. For each study, the design, population, exposures, main results, and conclusion were extracted. The research questions and the risk-of-bias information were also extracted. Additionally, the risk-of-bias were analyzed to guarantee the reliability of this review.

DATA ANALYSIS

A qualitative analysis revealed that FOSs can increase bifidobacteria counts and short-chain fatty acids in the gut, stimulate IgA secretion in the colon, and decrease proinflammatory cytokines, thus influencing metabolic diseases.

CONCLUSION

Studies suggest that FOS supplementation is positively associated with an anti-inflammatory and antioxidant effect, thus enhancing the gut immune system, which may be beneficial for the host's health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration nos 42020209865 and 42020220369.

Nutrient, Fibre, and FODMAP Intakes and Food-related Quality of Life in Patients with Inflammatory Bowel Disease, and Their Relationship with Gastrointestinal Symptoms of Differing Aetiologies

BACKGROUND AND AIMS

Certain foods are reported as gut symptom triggers in inflammatory bowel disease [IBD], and fructans are shown to worsen non-inflammatory symptoms in inactive IBD, which may result in self-imposed dietary restrictions. The aim of this study was to investigate nutrient and FODMAP intakes, and the relationship between gut symptoms and dietary intake, in IBD.

METHODS

Nutrient, fibre, and FODMAP intakes were estimated using 7-day food records in patients with active IBD [Active IBD], inactive IBD with non-inflammatory gut symptoms [Inactive IBD-GI], inactive IBD without gut symptoms [Inactive IBD], and healthy controls. Nutrient intakes, numbers of participants achieving national recommendations, and food-related quality of life [FR-QoL] were compared across study groups.

RESULTS

Food diaries were obtained from 232 patients with IBD [65 Active IBD, 86 Inactive IBD-GI, 81 Inactive IBD] and 84 healthy controls. Patients with Active IBD had significantly lower intakes of numerous micronutrients, including iron, folate, and vitamin C, compared with controls. All IBD groups consumed less total fibre [4.5 to 5.8 g/day] than controls [p = 0.001], and total FODMAP and fructan intakes were lower in Active IBD compared with controls. Strikingly, FR-QoL was significantly lower in all IBD groups compared with controls [all p = 0.001].

CONCLUSIONS

This study revealed lower intakes of fibre, FODMAPs, and micronutrients, in addition to poorer FR-QoL, in Active IBD and Inactive IBD-GI with gut symptoms compared with healthy controls. Future research should address dietary restrictions responsible for these differences.

Bifidobacterium dentium-derived y-glutamylcysteine suppresses ER-mediated goblet cell stress and reduces TNBS-driven colonic inflammation

Endoplasmic reticulum (ER) stress compromises the secretion of MUC2 from goblet cells and has been linked with inflammatory bowel disease (IBD). Although Bifidobacterium can beneficially modulate mucin production, little work has been done investigating the effects of Bifidobacterium on goblet cell ER stress. We hypothesized that secreted factors from Bifidobacterium dentium downregulate ER stress genes and modulates the unfolded protein response (UPR) to promote MUC2 secretion. We identified by mass spectrometry that B. dentium secretes the antioxidant γ-glutamylcysteine, which we speculate dampens ER stress-mediated ROS and minimizes ER stress phenotypes. B. dentium cell-free supernatant and γ-glutamylcysteine were taken up by human colonic T84 cells, increased glutathione levels, and reduced ROS generated by the ER-stressors thapsigargin and tunicamycin. Moreover, B. dentium supernatant and γ-glutamylcysteine were able to suppress NF-kB activation and IL-8 secretion. We found that B. dentium supernatant, γ-glutamylcysteine, and the positive control IL-10 attenuated the induction of UPR genes GRP78, CHOP, and sXBP1. To examine ER stress in vivo, we first examined mono-association of B. dentium in germ-free mice which increased MUC2 and IL-10 levels compared to germ-free controls. However, no changes were observed in ER stress-related genes, indicating that B. dentium can promote mucus secretion without inducing ER stress. In a TNBS-mediated ER stress model, we observed increased levels of UPR genes and pro-inflammatory cytokines in TNBS treated mice, which were reduced with addition of live B. dentium or γ-glutamylcysteine. We also observed increased colonic and serum levels of IL-10 in B. dentium- and γ-glutamylcysteine-treated mice compared to vehicle control. Immunostaining revealed retention of goblet cells and mucus secretion in both B. dentium- and γ-glutamylcysteine-treated animals. Collectively, these data demonstrate positive modulation of the UPR and MUC2 production by B. dentium-secreted compounds.

In vitro metabolic capacity of carbohydrate degradation by intestinal microbiota of adults and pre-frail elderly

Globally increased life expectancy strongly triggered interest to delay the onset of frailty, which has been associated with alterations in compositional and functional characteristics of intestinal microbiota. In the current study, we used an in vitro batch incubation model to compare the metabolic capacity of the faecal microbiota of adults (n = 6) versus pre-frail elderly (n = 6) to degrade various glycosidic carbohydrates, including galacto-oligosaccharides, 2'-fucosyllactose, chicory fructo-oligosaccharides and inulin, and isomalto/malto-polysaccharides. The in vitro metabolic capacity was also compared with an in vivo GOS intervention study based on the same subjects. Analysis of 16S rRNA gene sequences and metabolites revealed distinct portions of variation in overall microbiota and metabolite composition during incubation being explained by individuality of the subjects and carbon source. In addition, the age group of the subjects also had significant impact on microbiota variation, carbohydrate degradation and metabolite production. This was accompanied by elevated increase in the relative abundance of Bifidobacterium in the microbiota of adults compared to that of pre-frail elderly and significantly decreased effectiveness to degrade galacto-oligosaccharides by the latter group. Altogether, the carbohydrate degradation in elderly was different compared to adults, with some carbohydrates showing decreased degradation rates. Longer interventions periods may be required to enhance bifidobacterial abundance in the microbiota of pre-frail elderly and thereby to obtain associated prebiotic health benefits.

Aloe barbadensis Mill. extract improves symptoms in IBS patients with diarrhoea: post hoc analysis of two randomized double-blind controlled studies

BACKGROUND

Aloe barbadensis Mill. (Aloe) extract was found to be well-tolerated, safe and showed beneficial effects in subsets of irritable bowel syndrome (IBS) patients in two randomized, double-blind, controlled studies. However, the individual studies were underpowered to perform subgroup analyses. We therefore determined the effect of Aloe extract in IBS subgroups in a post hoc analysis combining the results from the two studies.

METHODS

Data from the two controlled studies comparing Aloe and control treatment taken orally for 4 weeks, were pooled. Both studies included IBS patients fulfilling the ROME III criteria and IBS Symptom Severity Score (IBS-SSS) was assessed. We analysed the effect of Aloe extract on IBS symptom severity and the proportion of responders (IBS-SSS reduction ⩾ 50) in IBS subgroups.

RESULTS

In total, 213 IBS patients were included in the post hoc subgroup analyses. A reduction in overall symptom severity, primarily driven by effect on pain severity and frequency, comparing baseline versus end of treatment, was recorded in IBS patients with diarrhoea (IBS-D) receiving Aloe (n = 38, p < 0.001) but not control treatment (n = 33, p = 0.33), with difference between the treatment groups (p = 0.01). Moreover, the frequency of responders was higher in IBS-D patients receiving Aloe (n = 22, 58%) compared to control treatment (n = 10, 30%) (p = 0.02). The effect of Aloe extract treatment on IBS symptom severity was not superior to control treatment in the other IBS subtypes.

CONCLUSION

Aloe extract improves symptom severity in IBS-D patients and can be regarded as a safe and effective treatment option for this patient group.

In vitro fecal fermentation profiles and microbiota responses of pulse cell wall polysaccharides: enterotype effect

The gut microbiota community of individuals is predominated by diverse fiber-utilizing bacteria, and might have distinct fermentation outcomes for a given dietary substrate. In this research, we isolated pea cell walls (PCWs) from cotyledon seeds, and performed the in vitro fecal fermentation by individual Prevotella- and Bacteroides-enterotype inocula. The Prevotella-enterotype inoculum showed a higher fermentation rate and produced more short-chain fatty acids (SCFAs), especially propionate and butyrate, throughout the entire fermentation period from PCW degradation compared with the Bacteroides-enterotype one. Furthermore, the better monosaccharide utilization capacity of Prevotella-enterotype inoculum was shown, compared to the Bacteroides-enterotype inoculum. PCW fermentation with Prevotella- and Bacteroides-enterotype inocula resulted in different microbial changes, and the abundance of Prevotella and Bacteroides was promoted, respectively. These results may contribute to predicting the responses of Prevotella and Bacteroides enterotypes to diets and offer useful information in personalized nutrition.

Prebiotic Inulin Supplementation and Peripheral Insulin Sensitivity in adults at Elevated Risk for Type 2 Diabetes: A Pilot Randomized Controlled Trial

Prediabetes affects 84.1 million adults, and many will progress to type 2 diabetes (T2D). The objective of this proof-of-concept trial was to determine the efficacy of inulin supplementation to improve glucose metabolism and reduce T2D risk. Adults (n = 24; BMI: 31.3 ± 2.9 kg/m²; age: 54.4 ± 8.3 years) at risk for T2D were enrolled in this controlled feeding trial and consumed either inulin (10 g/day) or placebo (maltodextrin, 10 g/day) for six weeks. Assessments included peripheral insulin sensitivity, fasting glucose, and insulin, HOMA-IR, in vivo skeletal muscle substrate preference, Bifidobacteria copy number, intestinal permeability, and endotoxin concentrations. Participant retention was 92%. There were no baseline group differences except for fasting insulin (p = 0.003). The magnitude of reduction in fasting insulin concentrations with inulin (p = 0.003, inulin = Δ-2.9, placebo = Δ2.3) was attenuated after adjustment for baseline concentrations (p = 0.04). After adjusting for baseline values, reduction in HOMA-IR with inulin (inulin = Δ-0.40, placebo=Δ0.27; p = 0.004) remained significant. Bifidobacteria 16s increased (p = 0.04; inulin = Δ3.1e⁹, placebo = Δ-8.9e⁸) with inulin supplementation. Despite increases in gut Bifidobacteria, inulin supplementation did not improve peripheral insulin sensitivity. These findings question the need for larger investigations of inulin and insulin sensitivity in this population.

Manipulation of Gut Microbiota Using Acacia Gum Polysaccharide

Acacia gum (AG) is a branched-polysaccharide gummy exudate that consists of arabinose and galactose. The traditional practice in African-Middle Eastern countries uses this gum as medicine. Traditional use of AG is to treat stomach disease, which can be a potential functional food. In this research, commercially available AG from Acacia senegal and Acacia seyal was investigated as the prebiotic. The experiment employed a pH-controlled in vitro colon model inoculated with human fecal microbiota to mimic the human colon. Fermentation samples at 0, 6, 12, and 24 h were brought for short-chain fatty acid (SCFA) analysis using high-performance liquid chromatography and bacterial enumeration via fluorescent in situ hybridization. Results showed that AG significantly promotes Bifidobacteria proliferation similar to fructo-oligosaccharides (FOS) while inhibiting the Clostridium histolyticum group, commonly associated with gut dysbiosis. Acetate, propionate, and butyrate showed a similar trend to FOS (p > 0.05). The AG shows potential against gut dysbiosis, as it promotes gut-probiotics, through modulation of microbial population and SCFA production, especially butyrate.

Fermentation of Pleurotus ostreatus and Ganoderma lucidum mushrooms and their extracts by the gut microbiota of healthy and osteopenic women: potential prebiotic effect and impact of mushroom fermentation products on human osteoblasts

Recent data have highlighted the role of the gut microbiota and its several metabolites in maintaining bone health. Thus, gut microbiota manipulation, e.g., by prebiotics, might offer a plausible target in the fight against bone degenerative diseases. This study aimed (a) to investigate the in vitro prebiotic potential of Ganoderma lucidum and Pleurotus ostreatus mushrooms in healthy and osteopenic women and (b) to explore the impact of mushroom fermentation products on human osteoblasts. G. lucidum LGAM 9720 and P. ostreatus IK 1123 lyophilized mushroom-powders (2% w/v) and their hot-water extracts (1% w/v) were fermented in a 24 h static batch culture model by using faecal inocula from healthy (n = 3) or osteopenic (n = 3) donors. Gut microbiota analysis (qPCR) and measurement of short chain fatty acids (SCFAs) were performed during fermentation, and 24 h-prebiotic indexes were calculated. Evaluation of the effects of fermentation products on bone metabolism parameters (OPG: osteoprotegerin; and RANKL: receptor activator of nuclear factor kappa B ligand) in osteoblast cultures was also performed. Our data suggest that the origin of the gut microbiota inoculum plays a major role in the viability of osteoblasts. The treatments using P. ostreatus mushroom-powder and G. lucidum mushroom-extract had positive effects based on gut microbiota and SCFA analyses. Both mushrooms exhibited lower RANKL levels compared to controls, whereas their extracts tended to enhance the osteoblastic activity. In conclusion, mushrooms that are rich in beta-glucans may exert beneficial in vitro effects on bone physiology by alterations in the gut microbiota and/or SCFA production.

Partial characterization of novel inulin-like prebiotic fructooligosaccharides of Sechium edule (Jacq.) Sw. (Cucurbitaceae) tuberous roots

The fruits and aerial parts of Sechium edule (Jacq.) Sw. (Cucurbitaceae) are a popular cook vegetable being used in different parts of the world with ethnomedicinal and pharmacological values. However, the beneficial health attributes of the tuberous roots have been less exploited. The present study aimed to determine the prebiotic potentiality of the storage carbohydrates from this part. The carbohydrate fractions were harvested by hot-water, cold-water, hot-acid, hot-alkali, and hot 80% ethanol treatments following the standard protocol. The fractions were tested for in vitro prebiotic efficacy, hypocholesterolemic and antioxidant potentials, and in vivo health attributes in Swiss albino mice. The partial characterization was performed by high-performance thin-layer chromatography (HPTLC) and spectroscopic analyses by Fourier-transform infrared spectroscopy (FT-IR) and electrospray ionization mass spectrometry (ESI-MS). The highest prebiotic index was observed in hot-water and ethanol (Et-OH) fractions with the antioxidant IC₅₀ values of 35.46 ± 0.33 and 32.56 ± 0.48 µg/ml, respectively. The HPTLC, FT-IR, and ESI-MS analyses showed that the hot-water and Et-OH carbohydrate fractions are rich in low-degree polymerizing inulin-like fructooligosaccharides (FOS). The fractions had a significant prebiotic index, hypocholesterolemic, and antioxidant activities. The synbiotic combination of the fractions with the probiotic LAB improved gut colonization and gut immune enhancement with significantly lowered triglycerides, serum LDL, and serum VLDL cholesterols. A significantly enhanced HDL cholesterol level proves its health beneficial attributes comparable to the commercial inulin prebiotics. Thus, this plant's novel inulin-like FOS may substitute the high-cost commercial prebiotics for our daily life. PRACTICAL APPLICATIONS: Prebiotics are low-degree polymerizing oligosaccharide food ingredients having multifaceted health benefits. For this reason, there is an ever-increasing global demand for such novel prebiotics. Therefore, finding out some novel prebiotic from conventional food sources may provide an alternative dietary source to fulfill the consumer demand. Sechium edule is a famous cook vegetable used by many ethnic communities across the globe. For the first time, the study revealed novel inulin-like fructooligosaccharides in the tuberous roots having hypocholesterolemic and synbiotic efficacy with GRAS lactic acid bacteria.

Production and prebiotic properties of oligofructans from sugarcane juice fermentation by Bacillus subtilis TISTR 001

Oligofructans are potential biological substances that due to their distinctive properties have a positive health-promoting effect. This research aimed to produce oligofructans using sugarcane juice fermentation with Bacillus subtilis TISTR 001 and to study the prebiotic properties in vitro. The results showed that the maximum total oligofructans in the form of free fructose was 2.57% (w/v) at the 84th hour of fermentation with 0.17 g/g reducing sugar and a production yield of 0.031 g/L/h and maximum levansucrase activity of 1.57 × 106 U/mL at that time. The oligofructans contained in the fermented juice had potential functional ingredients that exhibited prebiotic properties that could resist the digestion of enzymes in the gastrointestinal tract under in vitro conditions with digestion of only 6.92%. In addition, the fermented juice promoted the growth of prebiotics, especially Bifidobacterium bifidum TISTR 2129 and inhibited the growth of pathogens using both single culturing and co-culturing with probiotics.

Protocol for a pilot single-centre, parallel-arm, randomised controlled trial of dietary inulin to improve gut health in solid organ transplantation: the DIGEST study

Introduction

Kidney transplantation remains the best treatment for end-stage kidney disease, however the requirement for indefinite immunosuppression increases the risk of cardiovascular disease, cancer and infection, leading to a reduction in long-term patient and graft survival. The gut microbiome is a critical determinant of health and modulates host immunity and metabolism through a number of recognised pathways, including through the production of immunomodulatory short-chain fatty acids (SCFA). Dietary supplementation with non-digestible fibre can augment the microbial production of SCFA and lead to favourable immune and metabolic outcomes, although this has yet to be shown in human kidney transplant recipients.

Methods and analysis

Dietary inulin for gut health in solid-organ transplantation (DIGEST) is a single-centre, unblinded, pilot parallel-arm randomised controlled trial designed to assess the feasibility and adherence of dietary inulin, a naturally occurring dietary fibre, in the early post-transplant period in kidney transplant recipients. Participants will be randomised at day 28 post-transplant to a 4-week period of dietary inulin (10–20 g/day) in addition to standard care, or standard care alone, and followed-up until week 12 post-transplant.

The primary outcomes of the study are: (i) the feasibility of participant recruitment, randomisation and retention; (ii) adherence to the intervention (inulin) and (iii) the tolerability of inulin determined by changes in gastrointestinal symptoms as scored on the Gastrointestinal Symptom Rating Scale.

Secondary outcomes include: (1) glycaemic variability determined by continuous glucose monitoring; (2) abundance of SCFA-producing microbiota, as determined by 16s rRNA sequencing of the faecal metagenome; (3) serum SCFA concentrations; (4) peripheral blood immune cell populations; (5) recipient inflammatory and metabolic profiles and (6) the incidence of biopsy-proven acute rejection and kidney function determined by estimated glomerular filtration rate.

Ethics and dissemination

All study visits, clinical and laboratory assessments will be integrated into usual post-transplant care, creating no additional healthcare encounters or procedures. The risks associated with this study are minor. Inulin has been shown to be well tolerated across a variety of cohorts, with the occurrence of short-term adverse gastrointestinal symptoms self-limiting. However, with gastrointestinal adverse events common following kidney transplantation, the tolerability of inulin in this cohort remains unknown. The results of DIGEST will be published in peer-reviewed journals and presented at academic conferences. This study has been approved by the Sydney Local Health District’s Ethics Committee (Royal Prince Alfred Hospital Zone).

Trial registration number

ACTRN12620000623998.

Structurally complex carbohydrates maintain diversity in gut-derived microbial consortia under high dilution pressure

Dietary fibers are major substrates for maintaining and shaping gut microbiota, but the structural specificity of these fibers for the diversity, structure and function of gut microbiota are poorly understood. Here, we employed an in vitro sequential batch fecal culture approach to address two ecological questions: (i) whether the chemical complexity of a carbohydrate influences its ability to maintain microbial diversity against high dilution pressure (ii) whether substrate structuring or obligate microbe-microbe metabolic interactions (e.g. exchange of amino acids or vitamins) exert more influence on maintained diversity. Sorghum arabinoxylan (SAX, a complex polysaccharide), inulin (a low-complexity oligosaccharide) and their corresponding monosaccharide controls were selected as model carbohydrates. Our results demonstrate that complex carbohydrates stably sustain diverse microbial consortia. Furthermore, other metabolic interactions were less influential in structuring microbial consortia consuming SAX than inulin. Finally, very similar final consortia were enriched on SAX from the same individual's fecal microbiota one month later, suggesting that polysaccharide structure is more influential than stochastic alterations in microbiome composition in governing the outcomes of sequential batch cultivation experiments. These data suggest that carbohydrate structural complexity affords independent niches that structure fermenting microbial consortia, whereas other metabolic interactions govern the composition of communities fermenting simpler carbohydrates.

Immune status, well-being and gut microbiota in military supplemented with synbiotic ice cream and submitted to field training: a randomised clinical trial

Strenuous physical activity, sleep deprivation and psychological stress are common features of military field training. The present study aimed to evaluate the effects of supplementation with a synbiotic ice cream on salivary IgA, gastrointestinal symptoms, well-being indicators and gut microbiota in young military participants undergoing field training. Sixty-five military completed the study: one group was supplemented for 30 d with synbiotic ice cream containing: 2·1 × 108 CFU/g for Lactobacillus acidophilus LA-5 and 2·7 × 109 CFU/g for Bifidobacterium animalis BB-12 and 2·3 g of inulin in the 60 g of ice cream at manufacture, and the other with a placebo ice cream. Volunteers were evaluated at pre-supplementation (baseline), post-supplementation and after a 5-d military training. Bifidobacterium and Lactobacillus genera were measured in stool samples and both showed a higher differential abundance post-supplementation and training. Salivary IgA and gastrointestinal symptoms decreased at post-training in both groups (P < 0·05; main effect of time); however, supplementation with synbiotic did not mitigate this effect. Tenseness and sleepiness were decreased in the synbiotic-treated group, but not in the placebo group at post-military training (P = 0·01 and 0·009, respectively; group × time effect). The other well-being indicators were not affected by the synbiotic supplementation. In conclusion, 30 d of synbiotic ice cream supplementation containing inulin, L. acidophilus LA-5 and B. animalis BB-12 favourably modulated gut microbiota and improved tenseness and sleepiness in healthy young military undergoing a 5-d field training. These improvements may be relevant to this population as they may influence the decision-making process in an environment of high physical and psychological stress.

A cross-sectional analysis from the Mykinso Cohort Study: establishing reference ranges for Japanese gut microbial indices

The purpose of this study was to establish reference ranges for gut microbial indices by collecting real-world Japanese microbiome data from a Mykinso cohort. Although several large cohort studies have focused on the human gut microbiome, large cohort studies of the gut microbiome from Japanese populations are scarce, especially from healthy or non-diseased individuals. We collected stool samples and original survey lifestyle information from 5,843 Japanese individuals through the Mykinso gut microbiome testing service. From the obtained 16S rRNA sequence data derived from stool samples, the ratio and distribution of each taxon were analyzed. The relationship between different epidemiological attributes and gut microbial indicators were statistically analyzed. The qualitative and quantitative indicators of these common gut microbiota were confirmed to be strongly correlated with age, sex, constipation/diarrhea, and history of lifestyle-related diseases. Therefore, we set up a healthy sub-cohort that controlled for these attribute factors and defined reference ranges from the distribution of gut microbial index in that population. Taken together, these results show that the gut microbiota of Japanese people had high beta-diversity, with no single "typical" gut microbiota type. We believe that the reference ranges for the gut microbial indices obtained in this study can be new reference values for determining the balance and health of the gut microbiota of an individual. In the future, it is necessary to clarify the clinical validity of these reference values by comparing them with a clinical disease cohort.

Bifidobacteriumlongum subsp. infantis CECT7210 (B. infantis IM-1®) Displays In Vitro Activity against Some Intestinal Pathogens

Certain non-digestible oligosaccharides (NDO) are specifically fermented by bifidobacteria along the human gastrointestinal tract, selectively favoring their growth and the production of health-promoting metabolites. In the present study, the ability of the probiotic strain Bifidobacterium longum subsp. infantis CECT7210 (herein referred to as B. infantis IM-1^®) to utilize a large range of oligosaccharides, or a mixture of oligosaccharides, was investigated. The strain was able to utilize all prebiotics screened. However, galactooligosaccharides (GOS), and GOS-containing mixtures, effectively increased its growth to a higher extent than the other prebiotics. The best synbiotic combination was used to examine the antimicrobial activity against Escherichia coli, Cronobacter sakazakii, Listeria monocytogenes and Clostridium difficile in co-culture experiments. C. difficile was inhibited by the synbiotic, but it failed to inhibit E. coli. Moreover, Cr. sakazakii growth decreased during co-culture with B. infantis IM-1^®. Furthermore, adhesion experiments using the intestinal cell line HT29 showed that the strain IM-1^® was able to displace some pathogens from the enterocyte layer, especially Cr. sakazakii and Salmonella enterica, and prevented the adhesion of Cr. sakazakii and Shigella sonnei. In conclusion, a new synbiotic (probiotic strain B. infantis IM-1^® and GOS) appears to be a potential effective supplement for maintaining infant health. However, further studies are needed to go more deeply into the mechanisms that allow B.infantis IM-1^® to compete with enteropathogens.