Dietary xylo-oligosaccharide stimulates intestinal bifidobacteria and lactobacilli but has limited effect on intestinal integrity in rats

Oral amoxicillin treatment disrupts the gut microbiome and metabolome without interfering with luminal redox potential in the intestine of Wistar Han rats

Oral antibiotic treatment is well known to be one of the main factors affecting gut microbiota composition by altering bacterial diversity. It decreases the abundance of butyrate-producing bacteria such as Lachnospiraceae and Ruminococcaceae, while increasing abundance of Enterobacteriaceae. The recovery time of commensal bacteria post-antibiotic treatment varies among individuals, and often, complete recovery is not achieved. Recently, gut microbiota disruption has been associated with increased gut oxygen levels and higher redox potential in faecal samples. Given that redox balance is crucial for microbial metabolism and gut health, influencing fermentation processes and maintaining anaerobic conditions, we investigated the impact of oral amoxicillin treatment on the redox potential in the caecum. We used 24 Wistar Han male rats and measured caecal redox potential in situ with a probe, before and after 7 days of amoxicillin treatment, as well as after 7 days of recovery. Additionally, we analysed caecal weight, pH, antioxidant capacity, caecal microbiota, metabolome, and colonic tissue expression of relevant genes involved in the redox potential state. Our findings show that oral amoxicillin treatment significantly reduced archaeal load, and decreased the bacterial alpha diversity and affected bacterial composition of the caecal microbiome. The caecal metabolome was also significantly affected, exemplified by reduced amounts of short chain fatty acids during amoxicillin treatment. While the caecal metabolome fully recovered 7 days post amoxicillin treatment, the microbiome did not fully recover within this time frame. However, amoxicillin did not lead to an increase in luminal redox potential in the cecum during or post amoxicillin treatment. Limited differences were observed for colonic expression of genes involved in intestinal barrier function and generation of reactive oxygen species, except for the catalase gene, which was significantly upregulated post-amoxicillin treatment. Our results suggest that while oral amoxicillin disrupts the gut microbiome and metabolome, it does not directly interfere with gut luminal redox state.

Impact of in ovo administration of xylo- and mannooligosaccharides on broiler chicken gut health

The intestinal mucosa creates a connection between the gut microbiota and the host. This study aimed to modify the gut microbiota of broiler chickens by in ovo stimulation with xylo-oligosaccharide (XOS) and manno-oligosaccharide (MOS) prebiotics and to determine the changes occurring in specific gut segments. Three hundred incubated eggs of Ross 308 broiler chickens on the 12th d of incubation were injected with: saline (control), xylotriose (XOS3), xylotetrose (XOS4), mannotriose (MOS3) or mannotetrose (MOS4). Tissue and digesta samples were collected post-mortem from 8 randomly selected individuals from each group, on d 42 after hatching. Gene expression analysis in the cecum and ileum was performed by RT-qPCR for a panel of genes: innate immune response genes (IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-17, IL-1β, IFNγ, IFNβ), nutrient sensing and nutrient transport genes (FFAR2, FFAR4, GLUT1, GLUT2, GLUT5), host defence peptides (AvBD1, CATHL2), and barrier function genes (MUC6, CLDN1, TJAP). The relative abundance of bacteria was determined by qPCR for individual bacteria (Akkermansia muciniphilla, Bifidobacterium spp., Clostridium difficile, Escherichia coli, Faecalibacterium prausnitzii, and Lactobacillus spp.). Stimulation with prebiotics caused changes in the abundance of bacteria especially Lactobacillus spp. and Bifidobacterium spp. in the cecum. The abundance of both genera increased in each study group compared to the control group. The highest abundance of Bifidobacterium spp. in the ileum was found in the MOS3 group compared to the control group. There were changes in the XOS4 and MOS3 groups in the expression of: FFAR4, GLUT1, AvBD1, CATHL2, IL-2, IL-12, and IL-17 in the caecum. In conclusion, in ovo administration of prebiotics increased intestinal colonization by bacteria. The prebiotics influenced gene expression levels via changes in the gut microbiota.

Xylooligosaccharides alleviate the carbohydrate-enriched diet-induced intestinal barrier dysfunction in carp Megalobrama amblycephala by promoting intestinal development, immunity and gut microbiota

To date, although the high-carbohydrate (HC) feed has been extensively adopted in the aquaculture industry, its effects on the intestinal function and development of aquatic animals still remain unclear. In addition, the corresponding nutritional intervention is still barely reported. This study aimed to evaluate the influence of xylooligosaccharides (XOS) on the intestinal health of Megalobrama amblycephala subjected to a HC feeding. Fish (average weight: 44.55 ± 0.15 g) were randomly offered 3 diets, including a control one (29 % carbohydrate), a HC one (41 % carbohydrate), and a XOS supplemented one (HC + 1.0 % XOS, HCX) respectively for 12 weeks. The HC feeding caused morphological abnormalities of intestine, an increased intestinal permeability, and the intestinal immunosuppression, all of which were markedly reversed by XOS administration. In addition, compared with the HC group, HCX feeding remarkably promoted the intestinal activities of digestive and brush border enzymes, and the expressions of cell proliferation-related proteins (Wnt10b and Cyclin D1). The 16s rDNA sequencing also revealed that XOS administration increased the abundance of beneficial bacteria, and decreased that of pathogenic ones. In conclusion, dietary supplementation of XOS improved the intestinal histomorphology, barrier function, cell proliferation and bacterial communities of carbohydrate-overloaded fish Megalobrama amblycephala.

In vitro and in vivo investigation of the biological action of xylooligosaccharides derived from industrial waste

Xylooligosaccharides (XOS) are prebiotics of significant biological value that can be obtained through cost-effective purification of agricultural waste. The present research featured in vitro and in vivo investigation of prebiotic effects of xylooligosaccharides derived from wheat bran powder and brewer's spent grain. Prebiotic activity of Lactobacillus. fermentum, Lactobacillus. casei, and Bifidobacterium spp. was investigated in vitro using standard selective media. 16S rRNA quantitative PCR used for in vitro and in vivo investigation quantified relative abundance of Bifidobacterium spp., Lactobacillus spp., and Akkermansia. muciniphila in samples of fecal matter, cecal content, and intestinal tissue. Research revealed a favorable association between XOS concentration and both bacterial count and diameter of resultant colonies. The standard strain of L. casei showed no noticeable effect on growth rate. Bifidobacterium spp. proliferation in intestinal tissue was validated via in vivo tests using XOS obtained from wheat bran powder and brewer's spent grain. Findings indicated increased prevalence of the A. muciniphila species and the presence of XOS showed a protective function in preserving the structural integrity of intestinal mucus secretions. The presence of XOS in food indicated direct association with proliferation of Bifidobacterium spp. and A. muciniphila spp. Study results suggest that XOS extracted through enzymatic hydrolysis in Mongolian food industry by-products such as wheat bran products and brewer's spent grain exhibit prebiotic properties that justify XOS manufacture on a large scale and incorporation of XOS as nutritional enhancement in food products and pharmaceuticals.

The effect of sodium butyrate administered in ovo on the health status and intestinal response in broiler chicken

A healthy gut is one of the main factors influencing bird response. Over the years, efforts have been made to improve intestinal health. One of the supporting methods may be enriching the diet with bioactive ingredients, including sodium butyrate (SB). One of the possible ways of administering such supplementation is in ovo technology. Over the years, research has shown that administering bioactive substances this way has a positive effect on the health status of chickens. The current study aimed to modify the gut microbiota of broiler chickens by in ovo stimulation on d 12 of egg incubation with SB and to determine the changes occurring in intestines. One thousand eggs were incubated and injected with 0.1, 0.3, or 0.5% SB on d 12 of incubation. The control group was injected with physiological saline. Samples collected for analysis were obtained postmortem from 42-day-old ROSS 308 broiler chickens. Growth performance parameters were also monitored during broiler rearing. Gene expression analysis showed significant changes in the levels of IL4, IFNγ, AvBD1, TJAP and MUC6 genes in the ileum. However, the IL8, MUC2 and MUC6 genes were significantly expressed in the cecal mucosa. These changes depended on the administered dose of butyrate. There was no effect of in ovo administration of various doses of SB on digesta pH, SCFA level and histological parameters. However, a significant increase in Bifidobacterium bacteria was detected in the ileum after administration of a dose of 0.5% SB and in the cecum after administration of a dose of 0.3%. Administration of SB in ovo has the potential to support intestinal health in poultry. The effects depend on the administered dose, while the results indicate a dose of 0.3% as the most optimal.

The effect of coffee husks used as pellet bedding material on the intestinal barrier, immune-related gene expression and microbiota composition in the broiler chicken caecum

Introduction

Using coffee husks as waste material for bedding contributes to sustainable development. A sustainable choice of bedding has also, however, to be a safe choice for poultry. The study analysed immune-related gene expression in the intestinal mucosa and indicator bacteria in caecal content collected from broiler chickens bedded on material with coffee husk addition.

Material and Methods

One-day-old Ross 308 chickens were divided into four groups of 10 birds each in five replicates: C, the control group kept on wheat straw bedding; CH10, a group kept on bedding of 10% coffee husks and 90% wheat straw; CH25, a group kept on bedding of 25% husks and 75% straw; and CH50, a group kept on bedding of 50% husks and 50% straw. After 42 days, the birds were slaughtered, the caecal mucosae were removed for RNA isolation and the caecal content was collected for bacterial DNA isolation. The expression of genes involved in intestinal immune response and host organism defence and the relative abundance of indicator bacteria were analysed.

Results

Upregulation of the expression of genes related to the immune response and intestinal tightness was correlated with an increase in the percentage of coffee husks in the pellet. Coffee husk pellets at 50% bedding content caused a significant numerical increase in Bifidobacterium and a statistically significant increase in Lactobacillus. A significant reduction in E. coli bacteria was also demonstrated in this group. Coffee husk pellets at all content percentages resulted in a statistically significant diminution of the level of Streptococcus bacteria.

Conclusion

The addition of coffee husks to poultry litter effects beneficial changes in the expression of genes related to intestinal health and the caecal bacterial profile.

Thiamine-Reduced Fatigue in Quiescent Inflammatory Bowel Disease Is Linked to Faecalibacterium prausnitzii Abundance

Background and Aims

Chronic fatigue is common in patients with inflammatory bowel disease (IBD). The gut microbiota, specifically, microbial diversity and butyrate-producing bacteria have been linked to the fatigue pathogenesis. High-dose oral thiamine reduces fatigue, potentially through gut microbiota modification. In this study, we investigated how the gut microbiota influences the efficacy of high-dose thiamine in alleviating chronic fatigue in quiescent IBD (qIBD).

Methods

We analyzed the microbiota and short-chain fatty acids concentrations in fecal samples from patients with qIBD, with (n = 40) or without (n = 20) chronic fatigue. The 40 patients with qIBD and fatigue were included in a randomized, placebo-controlled, crossover trial to assess a 4-week high-oral-dose thiamine regimen.

Results

Butyrate and butyrate-producing bacteria were similar in patients with and without fatigue and did not change with high-dose thiamine treatment. Notably, Faecalibacterium prausnitzii was more abundant in thiamine responders compared with nonresponders both pretreatment (P = .019) and post-treatment (P = .038). The relative abundances of Faecalibacterium prausnitzii and Roseburia hominis, both pretreatment and post-treatment, inversely correlated with IBD fatigue score changes for patients with chronic fatigue (PRE; R = -0.48, P = .004, and R = -0.40, P = .018; POST; R = -0.42, P = .012, and R = -0.40, P = .017) respectively.

Conclusion

Faecalibacterium prausnitzii and Roseburia hominis may serve as markers for response to high-dose thiamine in alleviating chronic fatigue in patients with qIBD. The mechanistic role of gut bacteria and butyrate in patients with chronic fatigue and qIBD should be further explored.

A syrup containing L-arabinose and D-xylose appears superior to PEG-4000 as a bowel cleansing agent

Adequate bowel cleansing is crucial for endoscopic diagnosis and treatment, and the recovery of gut microbiota after intestinal cleansing is also important. A hypertonic syrup predominantly comprising L-arabinose and D-xylose (20% xylo-oligosaccharides) can be extracted from the hemicellulose of corn husks and cobs. L-Arabinose and xylo-oligosaccharides have been reported to relieve constipation and improve the gut microbial environment. This study evaluated the bowel cleansing effect of the aforementioned syrup and its influence on the organism and intestinal microbiota after cleansing in comparison with polyethylene glycol-4000 (PEG-4000) in mice. Bowel cleansing was performed using syrup or PEG-4000 in C57BL/6J mice, and the effect of intestinal preparation and its influence on serum electrolytes and gut microbiota after bowel cleansing were evaluated. The volume of intestinal residual feces in the syrup group was significantly lower than that in the PEG-4000 group. Additionally, syrup disturbed serum electrolytes more mildly than PEG-4000. Alpha diversity in the gut microbiota was significantly higher in the syrup group than in the PEG-4000 group on the first day after bowel cleansing. However, no difference in beta diversity was observed between the two groups. Syrup increased the abundance of Bifidobacteria and Christensenella and decreased the abundance of Akkermansia in comparison with PEG-4000 on the first day after bowel cleansing. Thus, this syrup has potential clinical use as a bowel cleansing agent given the above effects, its benefits and safety, and better taste and acceptability.

Recent Advances in Biomedical Applications of Mannans and Xylans

Plant-based phytochemicals, including flavonoids, alkaloids, tannins, saponins, and other metabolites, have attracted considerable attention due to their central role in synthesizing nanomaterials with various biomedical applications. Hemicelluloses are the second most abundant among naturally occurring heteropolymers, accounting for one-third of all plant constituents. In particular, xylans, mannans, and arabinoxylans are structured polysaccharides derived from hemicellulose. Mannans and xylans are characterized by their linear configuration of β-1,4-linked mannose and xylose units, respectively. At the same time, arabinoxylan is a copolymer of arabinose and xylose found predominantly in secondary cell walls of seeds, dicotyledons, grasses, and cereal tissues. Their widespread use in tissue engineering, drug delivery, and gene delivery is based on their properties, such as cell adhesiveness, cost-effectiveness, high biocompatibility, biodegradability, and low immunogenicity. Moreover, it can be easily functionalized, which expands their potential applications and provides them with structural diversity. This review comprehensively addresses recent advances in the field of biomedical applications. It explores the potential prospects for exploiting the capabilities of mannans and xylans in drug delivery, gene delivery, and tissue engineering.

Identification of inulin-responsive bacteria in the gut microbiota via multi-modal activity-based sorting

Prebiotics are defined as non-digestible dietary components that promote the growth of beneficial gut microorganisms. In many cases, however, this capability is not systematically evaluated. Here, we develop a methodology for determining prebiotic-responsive bacteria using the popular dietary supplement inulin. We first identify microbes with a capacity to bind inulin using mesoporous silica nanoparticles functionalized with inulin. 16S rRNA gene amplicon sequencing of sorted cells revealed that the ability to bind inulin was widespread in the microbiota. We further evaluate which taxa are metabolically stimulated by inulin and find that diverse taxa from the phyla Firmicutes and Actinobacteria respond to inulin, and several isolates of these taxa can degrade inulin. Incubation with another prebiotic, xylooligosaccharides (XOS), in contrast, shows a more robust bifidogenic effect. Interestingly, the Coriobacteriia Eggerthella lenta and Gordonibacter urolithinfaciens are indirectly stimulated by the inulin degradation process, expanding our knowledge of inulin-responsive bacteria.

A prebiotic diet modulates the oral microbiome composition and results in the attenuation of oropharyngeal candidiasis in mice

Oral bacteria can influence the ability of Candida albicans to cause oropharyngeal candidiasis (OPC). We recently reported that a Lactobacillus johnsonii-enriched oral microbiota reduced C. albicans virulence in an immunosuppressed OPC mouse model. As a follow-up, in this work, we aimed to enrich the resident oral Lactobacillus communities with a prebiotic diet to further assess their effect on the severity of OPC. We tested the effect of a prebiotic xylo-oligosaccharides (XOS)-enriched diet in the oral global bacterial composition and severity of OPC. We assessed changes in the oral microbiome composition via 16S-rRNA gene high-throughput sequencing, validated by qPCR. The impact of the prebiotic diet on Candida infection was assessed by quantifying changes in oral fungal and bacterial biomass and scoring tongue lesions. Contrary to expectations, oral Lactobacillus communities were not enriched by the XOS-supplemented diet. Yet, XOS modulated the oral microbiome composition, increasing Bifidobacterium abundance and reducing enterococci and staphylococci. In the OPC model, the XOS diet attenuated Candida virulence and bacterial dysbiosis, increasing lactobacilli and reducing enterococci on the oral mucosa. We conclude that XOS attenuates Candida virulence by promoting a bacterial microbiome structure more resilient to Candida infection. IMPORTANCE This is the first study on the effects of a prebiotic diet on the oral mucosal bacterial microbiome and an oropharyngeal candidiasis (OPC) mouse model. We found that xylo-oligosaccharides change the oral bacterial community composition and attenuate OPC. Our results contribute to the understanding of the impact of the oral bacterial communities on Candida virulence.

Alterations in the Fecal Microbiota Composition in Pediatric Acute Diarrhea: A Cross-Sectional and Comparative Study of Viral and Bacterial Enteritis

Objective

To examine the association between the fecal microbiota of acute diarrhea in children and provide gut microbiota information related the acute diarrhea with rotavirus.

Patients and Methods

Children with acute diarrhea aged 3-60 months were selected for the study. Routine stool examination was performed, and stool samples were collected and stored at -80 °C until further analysis. Fecal microbial DNA was extracted, and DNA concentration and quality were detected. PCR amplification and 16S rDNA high-throughput sequencing analysis using the Illumina MiSeq platform were performed, and intestinal flora was statistically analyzed.

Results

Children with acute diarrhea exhibited gut microbial dysbiosis. Lower microbial diversity and richness were observed in the viral enteritis and bacterial enteritis groups than in the control group. Composition of the microbiota in acute diarrhea differed from that in the control group. The Bacteroidetes/Firmicutes dramatically decreased in the viral enteritis and bacterial enteritis groups. However, the relative abundance of Proteobacteria and Fusobacteria increased, especially in the bacterial enteritis group. In addition, the relative abundance of Actinobacteria had dramatically increased in the viral enteritis group. According to the Kyoto Encyclopedia of Genes and Genomes map analysis, the membrane transport dysfunction was caused by rotavirus infection, while the membrane transport dysfunction was more evident in bacterial infection.

Conclusion

Acute diarrhea infections cause fecal microbiota dysbiosis in children. Changes in fecal microflora in children suggest that the regulation of intestinal flora in children with acute diarrhea should be strengthened.

Canagliflozin protects the cardiovascular system through effects on the gut environment in non-diabetic nephrectomized rats

BACKGROUND

The gut produces toxins that contribute to the cardiovascular complications of chronic kidney disease. Canagliflozin, a sodium glucose cotransporter (SGLT) 2 inhibitor that is used as an anti-diabetic drug, has a weak inhibitory effect against SGLT1 and may affect the gut glucose concentration and environment.

METHODS

Here, we determined the effect of canagliflozin on the gut microbiota and the serum gut-derived uremic toxin concentrations in 5/6th nephrectomized (Nx) rats.

RESULTS

Canagliflozin increased the colonic glucose concentration and restored the number of Lactobacillus bacteria, which was low in Nx rats. In addition, the expression of tight junction proteins in the ascending colon was low in Nx rats, and this was partially restored by canagliflozin. Furthermore, the serum concentrations of gut-derived uremic toxins were significantly increased by Nx and reduced by canagliflozin. Finally, the wall of the thoracic aorta was thicker and there was more cardiac interstitial fibrosis in Nx rats, and these defects were ameliorated by canagliflozin.

CONCLUSIONS

The increases in colonic glucose concentration, Lactobacillus numbers and tight junction protein expression, and the decreases in serum uremic toxin concentrations and cardiac interstitial fibrosis may have been caused by the inhibition of SGLT1 by canagliflozin because similar effects were not identified in tofogliflozin-treated rats.

Effect of Arabinoxylan and Xylo-Oligosaccharide on Growth Performance and Intestinal Barrier Function in Weaned Piglets

The purpose of this study was to explore the effects of xylose with different polymerizations on growth performance, intestinal barrier function, and gut microbial composition in weaned piglets. A total of 144 weaned piglets were assigned to 3 dietary treatments in a completely randomized design according to their body weight and sex. Dietary treatments included a corn-soybean meal basal diet (CON) and 2 additional diets formulated with 1% arabinoxylan (AX) and 1% xylo-oligosaccharide (XOS), respectively. Results showed that dietary supplementation of XOS or AX reduced diarrhea incidence of weaned piglets compared with the CON group (p < 0.05). XOS or AX increased the ileal villus height and intestinal activity of antioxidases in weaned piglets compared with the CON group (p < 0.05). XOS or AX reduced the ileal and colonic IL-6 content and increased the colonic sIgA and IL-10 concentrations in weaned piglets compared with the CON group (p < 0.05). XOS or AX increased the total organic acids concentrations in the ileum and in vitro fermentation (p < 0.05). XOS increased the abundance of Lactobacillus and Bifidobacterium in the ileal digesta (p < 0.05), while AX increased the population of Lactobacillus in the ileal digesta and the abundance of Bifidobacterium in the colonic digesta of weaned piglets (p < 0.05). In conclusion, both XOS and AX reduce diarrhea incidence and improve antioxidant capacity, immune function, and populations of beneficial bacteria, while microbial fermentation of XOS with a lower polymerization and molecular mass can produce more organic acids and an increased abundance of Lactobacillus and Bifidobacterium in the upper gut of weaned pigs compared with AX.

Intestinal protein uptake and IgE-mediated food allergy

Food allergy is affecting 5-8% of young children and 2-4% of adults and seems to be increasing in prevalence. The cause of the increase in food allergy is largely unknown but proposed to be influenced by both environmental and lifestyle factors. Changes in intestinal barrier functions and increased uptake of dietary proteins have been suggested to have a great impact on food allergy. In this review, we aim to give an overview of the gastrointestinal digestion and intestinal barrier function and provide a more detailed description of intestinal protein uptake, including the various routes of epithelial transport, how it may be affected by both intrinsic and extrinsic factors, and the relation to food allergy. Further, we give an overview of in vitro, ex vivo and in vivo techniques available for evaluation of intestinal protein uptake and gut permeability in general. Proteins are digested by gastric, pancreatic and integral brush border enzymes in order to allow for sufficient nutritional uptake. Absorption and transport of dietary proteins across the epithelial layer is known to be dependent on the physicochemical properties of the proteins and their digestion fragments themselves, such as size, solubility and aggregation status. It is believed, that the greater an amount of intact protein or larger peptide fragments that is transported through the epithelial layer, and thus encountered by the mucosal immune system in the gut, the greater is the risk of inducing an adverse allergic response. Proteins may be absorbed across the epithelial barrier by means of various mechanisms, and studies have shown that a transcellular facilitated transport route unique for food allergic individuals are at play for transport of allergens, and that upon mediator release from mast cells an enhanced allergen transport via the paracellular route occurs. This is in contrast to healthy individuals where transcytosis through the enterocytes is the main route of protein uptake. Thus, knowledge on factors affecting intestinal barrier functions and methods for the determination of their impact on protein uptake may be useful in future allergenicity assessments and for development of future preventive and treatment strategies.

Direct Action of Non-Digestible Oligosaccharides against a Leaky Gut

The epithelial monolayer is the primary determinant of mucosal barrier function, and tight junction (TJ) complexes seal the paracellular space between the adjacent epithelial cells and represent the main "gate-keepers" of the paracellular route. Impaired TJ functionality results in increased permeation of the "pro-inflammatory" luminal contents to the circulation that induces local and systemic inflammatory and immune responses, ultimately triggering and/or perpetuating (chronic) systemic inflammatory disorders. Increased gut leakiness is associated with intestinal and systemic disease states such as inflammatory bowel disease and neurodegenerative diseases such as Parkinson's disease. Modulation of TJ dynamics is an appealing strategy aiming at inflammatory conditions associated with compromised intestinal epithelial function. Recently there has been a growing interest in nutraceuticals, particularly in non-digestible oligosaccharides (NDOs). NDOs confer innumerable health benefits via microbiome-shaping and gut microbiota-related immune responses, including enhancement of epithelial barrier integrity. Emerging evidence supports that NDOs also exert health-beneficial effects on microbiota independently via direct interactions with intestinal epithelial and immune cells. Among these valuable features, NDOs promote barrier function by directly regulating TJs via AMPK-, PKC-, MAPK-, and TLR-associated pathways. This review provides a comprehensive overview of the epithelial barrier-protective effects of different NDOs with a special focus on their microbiota-independent modulation of TJs.

Xylan Prebiotics and the Gut Microbiome Promote Health and Wellbeing: Potential Novel Roles for Pentosan Polysulfate

This narrative review highlights the complexities of the gut microbiome and health-promoting properties of prebiotic xylans metabolized by the gut microbiome. In animal husbandry, prebiotic xylans aid in the maintenance of a healthy gut microbiome. This prevents the colonization of the gut by pathogenic organisms obviating the need for dietary antibiotic supplementation, a practice which has been used to maintain animal productivity but which has led to the emergence of antibiotic resistant bacteria that are passed up the food chain to humans. Seaweed xylan-based animal foodstuffs have been developed to eliminate ruminant green-house gas emissions by gut methanogens in ruminant animals, contributing to atmospheric pollution. Biotransformation of pentosan polysulfate by the gut microbiome converts this semi-synthetic sulfated disease-modifying anti-osteoarthritic heparinoid drug to a prebiotic metabolite that promotes gut health, further extending the therapeutic profile and utility of this therapeutic molecule. Xylans are prominent dietary cereal components of the human diet which travel through the gastrointestinal tract as non-digested dietary fibre since the human genome does not contain xylanolytic enzymes. The gut microbiota however digest xylans as a food source. Xylo-oligosaccharides generated in this digestive process have prebiotic health-promoting properties. Engineered commensal probiotic bacteria also have been developed which have been engineered to produce growth factors and other bioactive factors. A xylan protein induction system controls the secretion of these compounds by the commensal bacteria which can promote gut health or, if these prebiotic compounds are transported by the vagal nervous system, may also regulate the health of linked organ systems via the gut–brain, gut–lung and gut–stomach axes. Dietary xylans are thus emerging therapeutic compounds warranting further study in novel disease prevention protocols.

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.

Amoxicillin does not affect the development of cow’s milk allergy in a Brown Norway rat model

The use of antibiotics as well as changes in the gut microbiota have been linked to development of food allergy in childhood. It remains unknown whether administration of a single clinically relevant antibiotic directly promotes food allergy development when administrated during the sensitisation phase in an experimental animal model. We investigated whether the antibiotic amoxicillin affected gut microbiota composition, development of cow's milk allergy (CMA) and frequencies of allergic effector cells and regulatory T cells in the intestine. Brown Norway rats were given daily oral gavages of amoxicillin for six weeks and whey protein concentrate (WPC) with or without cholera toxin three times per week for the last five weeks. Microbiota composition in faeces and small intestine was analysed by 16S rRNA sequencing. The development of CMA was assessed by WPC‐specific IgE in serum, ear swelling response to WPC and body hypothermia following oral gavage of WPC. Allergic effector cells were analysed by histology, and frequencies of regulatory and activated T cells were analysed by flow cytometry. Amoxicillin administration reduced faecal microbiota diversity, reduced the relative abundance of Firmicutes and increased the abundance of Bacteroidetes and Proteobacteria. Despite these effects, amoxicillin did not affect the development of CMA, nor the frequencies of allergic effector cells or regulatory T cells. Thus, amoxicillin does not carry a direct risk for food allergy development when administrated in an experimental model of allergic sensitisation to WPC via the gut. This finding suggests that confounding factors may better explain the epidemiological link between antibiotic use and food allergy.

Protective Effect of Probiotics Isolated from Traditional Fermented Tea Leaves (Miang) from Northern Thailand and Role of Synbiotics in Ameliorating Experimental Ulcerative Colitis in Mice

This study aimed to investigate the protective effect of probiotics and synbiotics from traditional Thai fermented tea leaves (Miang) on dextran sulfate sodium (DSS)-induced colitis in mice, in comparison to sulfasalazine. C57BL/6 mice were treated with probiotics L. pentosus A14-6, CMY46 and synbiotics, L. pentosus A14-6 combined with XOS, and L. pentosus CMY46 combined with GOS for 21 days. Colitis was induced with 2% DSS administration for seven days during the last seven days of the experimental period. The positive group was treated with sulfasalazine. At the end of the experiment, clinical symptoms, pathohistological changes, intestinal barrier integrity, and inflammatory markers were analyzed. The probiotics and synbiotics from Miang ameliorated DSS-induced colitis by protecting body weight loss, decreasing disease activity index, restoring the colon length, and reducing pathohistological damages. Furthermore, treatment with probiotics and synbiotics improved intestinal barrier integrity, accompanied by lowing colonic and systemic inflammation. In addition, synbiotics CMY46 combined with GOS remarkedly elevated the expression of IL-10. These results suggested that synbiotics isolated from Miang had more effectiveness than sulfasalazine. Thereby, they could represent a novel potential natural agent against colonic inflammation.

The High Level of Xylooligosaccharides Improves Growth Performance in Weaned Piglets by Increasing Antioxidant Activity, Enhancing Immune Function, and Modulating Gut Microbiota

The aim of this study was to investigate the effects of the high level of xylooligosaccharides (XOS) on growth performance, antioxidant capability, immune function, and fecal microbiota in weaning piglets. The results showed that 28 d body weight exhibited linear and quadratic increases (P < 0.05) with increasing dietary XOS level, as well as average daily feed intake (ADFI) on d 15–28, average daily gain (ADG) on d 15–28 and 1–28. There was a linear decrease (P < 0.05) between XOS levels and feed conversion rate (FCR) on d 1–14 and 1–28. Additionally, glutathione peroxidase (GSH-Px) showed a linear increase (P < 0.05), while the malondialdehyde (MDA) level decreased linearly and quadratically (P < 0.05) with the increasing dietary level of XOS. Moreover, the XOS treatments markedly increased the levels of immunoglobulin A (Ig A) (linear, P < 0.05; quadratic, P < 0.05), IgM (quadratic, P < 0.05), IgG (linear, P < 0.05), and anti-inflammatory cytokine interleukin-10 (IL-10) (quadratic, P < 0.05) in serum, while the IL-1β (linear, P < 0.05; quadratic, P < 0.05) and IL-6 (linear, P < 0.05) decreased with increasing level of XOS. Microbiota analysis showed that dietary supplementation with 1.5% XOS decreased (P < 0.05) the α-diversity and enriched (P < 0.05) beneficial bacteria including Lactobacillus, Bifidobacterium, and Fusicatenibacter at the genus level, compared with the control group. Importantly, linearly increasing responses (P < 0.05) to fecal acetate, propionate, butyrate, and total short-chain fatty acids (SCFAs) were observed with increasing level of XOS. Spearman correlation analyses found that Lactobacillus abundance was positively correlated with ADG, acetate, propionate, and IgA (P < 0.05), but negatively correlated with IL-1β (P < 0.05). Bifidobacterium abundance was positively related with ADFI, total SCFAs, IgG, and IL-10 (P < 0.05), as well as g_Fusicatenibacter abundance with ADFI, total SCFAs, and IL-10. However, Bifidobacterium and Fusicatenibacter abundances were negatively associated with MDA levels (P < 0.05). In summary, dietary supplementation with XOS can improve the growth performance in weaning piglets by increasing antioxidant capability, enhancing immune function, and promoting beneficial bacteria counts.

Xylo-oligosaccharide alleviates Salmonella induced inflammation by stimulating Bifidobacterium animalis and inhibiting Salmonella colonization

Xylo-oligosaccharide (XOS), which is considered as a potential prebiotic, exhibits multiple beneficial effects on modulation of gut microbiota, strength of intestinal barrier, and inhibition of intestinal inflammation. The objective of this study is to investigate whether XOS protects against Salmonella infection by modulating gut microbiota, enhancing the intestinal barrier, and resisting colonization. C57BL/6 male mice received water supplementation with 5% XOS for 14 days before Salmonella Typhimurium infection. The results showed that XOS suppressed the Salmonella-induced inflammation, but had limited effects on tight junction molecules and mRNA expression of mucus proteins, except for claudin-1 in the colon. Data of 16S rDNA sequencing indicated that XOS modulated gut microbiota composition by significantly stimulating Bifidobacterium animalis (B. animalis), and reducing Salmonella counts. Therefore, the potential protective effects of B. animalis against Salmonella challenge were investigated as well. Bifidobacterium animalis subsp lactis BB-12 (BB12), which could markedly increase in XOS, was selected to treat mice. Similarly, Salmonella-induced inflammatory reactions were alleviated by BB12 but tight junction molecules and mucin proteins in the colonic tissues were not affected. Administration of BB12 remarkably decreased the copies of Salmonella in cecal digesta post Salmonella infection. Additionally, the decrease concentrations of cecal propionate and total short-chain fatty acids (SCFAs) in Salmonella-infected mice were reversed by BB12 treatment, and propionate performed a strong inhibitory effect on Salmonella growth in vitro. Besides that, BB12 could directly restrict Salmonella proliferation in vitro. Moreover, BB12 reduced the adhesion ability of Salmonella on the Caco-2 cells model. Our results suggest that XOS could be considered as a candidate of functional food to protect against Salmonella infection by stimulating Bifidobacterium, which then resists Salmonella colonization by maintaining the intestinal SCFAs levels and suppressing adhesibility.

Similarities and differences of oligo/poly-saccharides' impact on human fecal microbiota identified by in vitro fermentation

The dietary supplementation of prebiotics is considered a promising strategy for the modulation of gut microbiota. Due to the wide variety of animal models and tremendous inter-individual variability from human investigations, the prebiotic effect of fibers is often difficult to compare between studies. Here, the effects of 11 dietary fibers on human fecal microbiota were studied using an in vitro human fecal fermentation model under well-controlled conditions. All fibers showed positive regulatory effects on short chain fatty acids (SCFAs) and several beneficial bacteria, including Parabacteroides distasonis and Bifidobacterium spp. Cultures supplemented with xylo-oligosaccharide and konjac flour showed the highest SCFAs. According to regulatory effects, fibers were divided into three groups, with 13 indicator OTUs (operational taxonomic units) identified. Fecal microbiota regulated by isomalto-oligosaccharide and chitosan-oligosaccharide were similar to fructo-oligosaccharide and inulin outputs. As a supplement to in vivo studies, our results comprehensively summarized the similarities and distinctiveness of fibers in regulating fecal microbiota structures. KEY POINTS: • Fibers were divided into three groups based on the regulatory effects in microbiota. • Thirteen indicator OTUs were identified using pairwise comparisons. • Fiber similarities and distinctive traits in regulating microbiota effect were identified.

Chimeric bi-functional enzyme possessing xylanase and deacetylase activity for hydrolysis of agro-biomass rich in acetylated xylan

Here, a chimeric bifunctional enzyme was developed for two activities xylanase and deacetylase. Chimeric enzyme was designed by combining the relevant amino acid stretches from two different parent sequences, such as polysaccharide/xylan deacetylase (ref id: MT682066) and xylanase (ref id WP_110897546.1). Five different hypothetical chimeras were developed and one of the best predicted chimeric protein GA_2(syn_SKYAP01) was synthesized. The GA_2(syn_SKYAP01) possessed the specific activity of 14.905 ± 0.8 U/mg for deacetylase and 100.87 ± 14.2 U/mg for xylanase. Optimum level of both the activities together was achieved at pH 5 and 60 °C. The chimeric protein was also found to be stable at higher temperature of 71°C. Functionality of the developed chimeric protein for both the activities was confirmed by the hydrolysis of commercial xylan into xylooligosaccharides and the release of acetic acid from glucose pentacetate and 7-amino cephalosporin. The designed bifunctional enzyme was found to be highly efficient.

Western-style diet impedes colonization and clearance of Citrobacter rodentium

Western-style diet (WSD), which is high in fat and low in fiber, lacks nutrients to support gut microbiota. Consequently, WSD reduces microbiota density and promotes microbiota encroachment, potentially influencing colonization resistance, immune system readiness, and thus host defense against pathogenic bacteria. Here we examined the impact of WSD on infection and colitis in response to Citrobacter rodentium. We observed that, relative to mice consuming standard rodent grain-based chow (GBC), feeding WSD starkly altered the dynamics of Citrobacter infection, reducing initial colonization and inflammation but frequently resulting in persistent infection that associated with low-grade inflammation and insulin resistance. WSD's reduction in initial Citrobacter virulence appeared to reflect that colons of GBC-fed mice contain microbiota metabolites, including short-chain fatty acids, especially acetate, that drive Citrobacter growth and virulence. Citrobacter persistence in WSD-fed mice reflected inability of resident microbiota to out-compete it from the gut lumen, likely reflecting the profound impacts of WSD on microbiota composition. These studies demonstrate potential of altering microbiota and their metabolites by diet to impact the course and consequence of infection following exposure to a gut pathogen.

Combined effects of xylo-oligosaccharides and coated sodium butyrate on growth performance, immune function, and intestinal physical barrier function of broilers

This study was conducted to investigate the effects of dietary supplementation xylo-oligosaccharides (XOS), coated sodium butyrate (CSB), and their combination on growth performance, immune parameters, and intestinal barrier of broilers. A total of 192 1-day-old chicks were assigned to a 2 × 2 factorial design including two dietary additives (0 and 150 mg/kg XOS and 0 and 400 mg/kg CSB). This trial lasted for 42 days. CSB supplementation increased the thymus and bursa index, blood myeloperoxidase (MPO) activity, and IgG and IgM concentrations, whereas adding XOS only improved IgM concentration (p < .05). A significant interaction was observed for MPO activity. Furthermore, broilers fed CSB and their interaction exhibited increased ileal villus height/crypt depth (VH/CD) and goblet cells numbers in the ileum, as well as decreased ileal CD (p < .05). Broilers fed XOS and CSB individually showed higher ileal VH, the number of goblet cells in the duodenum and jejunum (p < .05). Moreover, XOS and CSB individual supplementation upregulated the expression of claudin3 in the ileum (p < .05). Simultaneously, a significant interaction was found for the ileal expression of claudin3. Overall, XOS and CSB supplementation could improve the development of immune organs, the small intestine morphology, and the intestinal physical barrier of broilers. Although no clear synergy of XOS and CSB was detected, the combination had positively affect broilers intestinal barrier and immune parameters.

Xylooligosaccharide attenuates lipopolysaccharide-induced intestinal injury in piglets via suppressing inflammation and modulating cecal microbial communities

Xylooligosaccharide (XOS) has been considered to be an effective prebiotic, but its exact mechanisms remain unknown. This research was conducted to evaluate the effects of XOS on pig intestinal bacterial community and mucosal barrier using a lipopolysaccharide (LPS)-caused gut damage model. Twenty-four weaned pigs were assigned to 4 treatments in a 2 × 2 factorial design involving diet (with or without XOS) and immunological challenge (saline or LPS). After 21 d of feeding 0% or 0.02% commercial XOS product, piglets were treated with saline or LPS. After that, blood, small intestinal mucosa and cecal digesta were obtained. Dietary XOS enhanced intestinal mucosal integrity demonstrated by higher villus height, villus height-to-crypt depth ratio, disaccharidase activities and claudin-1 protein expression and lower crypt depth. XOS also caused down-regulation of the gene expression of toll-like receptor 4 and nucleotide-binding oligomerization domain protein signaling, accompanied with decreased pro-inflammatory cytokines and cyclooxygenase 2 contents or mRNA expression and increased heat shock protein 70 mRNA and protein expression. Additionally, increased Bacteroidetes and decreased Firmicutes relative abundance were observed in the piglets fed with XOS. At the genus level, XOS enriched the relative abundance of beneficial bacteria, e.g., Faecalibacterium, Lactobacillus, and Prevotella. Moreover, XOS enhanced short chain fatty acids contents and inhibited histone deacetylases. The correlation analysis of the combined datasets implied some potential connections between the intestinal microbiota and pro-inflammatory cytokines or cecal metabolites. These results suggest that XOS inhibits inflammatory response and beneficially modifies microbes and metabolites of the hindgut to protect the intestine from inflammation-related injury.

Effects of Xylo-Oligosaccharides on Growth and Gut Microbiota as Potential Replacements for Antibiotic in Weaning Piglets

Xylo-oligosaccharides (XOS) is a well-known kind of oligosaccharide and extensively applied as a prebiotic. The objective of this study was to investigate the effect of XOS supplementation substituting chlortetracycline (CTC) on growth, gut morphology, gut microbiota, and hindgut short chain fatty acid (SCFA) contents of weaning piglets. A total of 180 weaned piglets were randomly allocated to three treatments for 28 days, as follows: control group (basal diet, CON), basal diet with 500 mg/kg (XOS500) XOS, and positive control (basal diet with 100 mg/kg CTC). Compared with the CON group, the piglets in the XOS500 group improved body weight (BW) on days 28, average daily gain (ADG) and reduced feed: gain ratio during days 1–28 (P < 0.05). The XOS500 supplementation increased Villus height and Villus height: Crypt depth ratio in the ileum (P < 0.05). Villus Height: Crypt Depth of the ileum was also increased in the CTC treatment group (P < 0.05). Meanwhile, the XOS500 supplementation increased significantly the numbers of goblet cells in the crypt of the cecum. High-throughput 16S rRNA gene sequencing revealed distinct differences in microbial compositions between the ileum and cecum. XOS500 supplementation significantly increased the bacterial diversity. However, CTC treatment markedly reduced the microbial diversity (P < 0.05). Meanwhile, XOS500 supplementation in the diet significantly increased the abundance of Lactobacillus genus compared to the CON and CTC group in the ileum and cecum (P < 0.01), whereas the level of Clostridium_sensu_stricto_1, Escherichia-Shigella, and Terrisporobacter genus in the XOS500 group were markedly lower than the CON and CTC group (P < 0.05). In addition, dietary supplementation with XOS500 significantly increased the total short-chain fatty acids, propionate and butyrate concentrations and decreased the acetate concentration compared to the CON group in the cecum (P < 0.05). In summary, dietary supplemented with XOS500 could enhance specific beneficial microbiota abundance and decrease harmful microbiota abundance to maintain the structure of the intestinal morphology and improve growth performance of weaned piglets. Thus, XOS may potentially function as an alternative to in-feed antibiotics in weaned piglets in modern husbandry.

Supplemental Xylooligosaccharide Modulates Intestinal Mucosal Barrier and Cecal Microbiota in Laying Hens Fed Oxidized Fish Oil

Our previous study indicated that dietary xylooligosaccharide (XOS) supplementation improved feed efficiency, ileal morphology, and nutrient digestibility in laying hens. The objective of this study was to evaluate the mitigative effects of XOS on intestinal mucosal barrier impairment and microbiota dysbiosis induced by oxidized fish oil (OFO) in laying hens. A total of 384 Hy-Line Brown layers at 50 weeks of age were randomly divided into four dietary treatments, including the diets supplemented with 20 g/kg of fresh fish oil (FFO group) or 20 g/kg of oxidized fish oil (OFO group), and the OFO diets with XOS addition at 200 mg/kg (OFO/XOS200 group) or 400 mg/kg (OFO/XOS400 group). Each treatment had eight replicates with 12 birds each. The OFO treatment decreased (P < 0.05) the production performance of birds from 7 to 12 weeks of the experiment, reduced (P < 0.05) ileal mucosal secretory immunoglobulin A (sIgA) content, and increased (P < 0.05) serum endotoxin concentration, as well as downregulated (P < 0.05) mRNA expression of claudin-1 (CLDN1) and claudin-5 (CLDN5) in the ileal mucosa at the end of the experiment. Dietary XOS addition (400 mg/kg) recovered (P < 0.05) these changes and further improved (P < 0.05) ileal villus height (VH) and the villus height-to-crypt depth ratio (VCR). In addition, OFO treatment altered cecal microbial composition of layers, and these alterations were probably involved in OFO-induced ileal mucosal impairment as causes or consequences. Supplemental XOS remodeled cecal microbiota of layers fed the OFO diet, characterized by an elevation in microbial richness and changes in microbial composition, including increases in Firmicutes, Ruminococcaceae, Verrucomicrobia (Akkermansia), Paraprevotella, Prevotella_9, and Oscillospira, along with a decrease in Erysipelatoclostridium. The increased abundance of Verrucomicrobia (Akkermansia) had positive correlations with the improved ileal VH and ileal mucosal expression of CLDN1. The abundance of Erysipelatoclostridium decreased by XOS addition was negatively associated with ileal VH, VCR, ileal mucosal sIgA content, and the relative expression of zonula occludens-2, CLDN1, and CLDN5. Collectively, supplemental XOS alleviated OFO-induced intestinal mucosal barrier dysfunction and performance impairment in laying hens, which could be at least partially attributed to the modulation of gut microbiota.

Effect of Xylo-Oligosaccharides Supplementation by Drinking Water on the Bone Properties and Related Calcium Transporters in Growing Mice

Xylo-oligosaccharides (XOS), non-digestible oligosaccharides, have the potential to regulate intestinal microorganisms, and thus, improve host health, but little evidence exists for the prebiotic effects on bone health. This study evaluates the dose-response effect of XOS supplementation on bone properties, the morphology of the intestine, cecum pH, and cecum wall weight, as well as the related calcium transporters. Ninety-six 28-day-old male mice were randomized into one of four groups, fed the same commercial diet, and given different types of deionized water containing 0, 1, 2, or 4% XOS by concentration for 30 days. Eight mice were randomly selected to accomplish particular tasks every 10 days. No significant differences in serum Ca and P levels and growth performance were observed among the four studied groups. XOS intervention significantly decreased cecum pH and increased cecum wall weight in a dose-dependent manner. At the late growth stage, compared with 0% XOS, the bone mineral density (BMD) and bone-breaking strength in 4% XOS were significantly higher. The bone crystallinity with 4% XOS, measured by Raman spectrum, was significantly enhanced compared to that with 0% XOS during later growth. The villus height and villus height to crypt depth (VH:CD) were enhanced with an increase of XOS concentration during the later stage of growth. The expression of transient receptor potential vanillin receptor 6 (TRPV6) and Na⁺/Ca²⁺ exchanger 1 (NCX1) in the duodenum were enhanced by XOS supplementation. XOS exerted a positive influence on bone properties by decreasing the cecum pH, increasing the cecum wall and villus structure, and upregulating the expression of related calcium transporters.

The role of mucin and oligosaccharides via cross-feeding activities by Bifidobacterium: A review

Bifidobacteria are one genus of low-abundance gut commensals that are often associated with host health-promoting effects. Bifidobacteria can degrade various dietary fibers (i.e., galactooligosaccharides, fructooligosaccharides, inulin), and are reported as one of the few gut-dwelling microbes that can utilize host-derived carbohydrates (mucin and human milk oligosaccharides). Previous studies have noted that the superior carbohydrate-metabolizing abilities of bifidobacteria facilitate the intestinal colonization of this genus and also benefit other gut symbionts, in particular butyrate-producing bacteria, via cooperative metabolic interactions. Given that such cross-feeding activities of bifidobacteria on mucin and oligosaccharides have not been systematically summarized, here we review the carbohydrate-degrading capabilities of various bifidobacterial strains that were identified in vitro experiments, the core enzymes involved in the degradation mechanisms, and social behavior between bifidobacteria and other intestinal microbes, as well as among species-specific bifidobacterial strains. The purpose of this review is to enhance our understanding of the interactions of prebiotics and probiotics, which sheds new light on the future use of oligosaccharides and bifidobacteria for nutritional intervention or clinical application.

Effects of dietary components on intestinal permeability in health and disease

Altered intestinal permeability plays a role in many pathological conditions. Intestinal permeability is a component of the intestinal barrier. This barrier is a dynamic interface between the body and the food and pathogens that enter the gastrointestinal tract. Therefore, dietary components can directly affect this interface, and many metabolites produced by the host enzymes or the gut microbiota can act as signaling molecules or exert direct effects on this barrier. Our aim was to examine the effects of diet components on the intestinal barrier in health and disease states. Herein, we conducted an in-depth PubMed search based on specific key words (diet, permeability, barrier, health, disease, and disorder), as well as cross references from those articles. The normal intestinal barrier consists of multiple components in the lumen, epithelial cell layer and the lamina propria. Diverse methods are available to measure intestinal permeability. We focus predominantly on human in vivo studies, and the literature is reviewed to identify dietary factors that decrease (e.g., emulsifiers, surfactants, and alcohol) or increase (e.g., fiber, short-chain fatty acids, glutamine, and vitamin D) barrier integrity. Effects of these dietary items in disease states, such as metabolic syndrome, liver disease, or colitis are documented as examples of barrier dysfunction in the multifactorial diseases. Effects of diet on intestinal barrier function are associated with precise mechanisms in some instances; further research of those mechanisms has potential to clarify the role of dietary interventions in treating diverse pathologic states.

Putative Mechanisms Responsible for the Antihyperglycemic Action of Lactobacillus paracasei HII01 in Experimental Type 2 Diabetic Rats

Despite the updated knowledge of the impact of gut dysbiosis on diabetes, investigations into the beneficial effects of individual bacteria are still required. This study evaluates the antihyperglycemic efficacy of Lactobacillus paracasei HII01 and its possible mechanisms in diabetic rats. Diabetic rats were assigned to receive vehicle, L. paracasei HII01 (10⁸ CFU/day), metformin 30 (mg/kg) or a combination of L. paracasei HII01 and metformin. Normal rats given vehicle and L. paracasei HII01 were included. Metabolic parameters, including in vitro hemi-diaphragm glucose uptake, skeletal insulin-signaling proteins, plasma lipopolysaccharide (LPS), gut permeability, composition of gut microbiota and its metabolites, as well as short-chain fatty acids (SCFAs), were assessed after 12 weeks of experiment. The results clearly demonstrated that L. paracasei HII01 improved glycemic parameters, glucose uptake, insulin-signaling proteins including pAkt^Ser473, glucose transporter 4 (GLUT4) and phosphorylation of AMP-activated protein kinase (pAMPK^Thr172), tumor necrosis factor (TNF-α) and nuclear factor-κB (NF-kB) in diabetic rats. Modulation of gut microbiota was found together with improvement in leaky gut, endotoxemia and SCFAs in diabetic rats administered L. paracasei HII01. In conclusion, L. paracasei HII01 alleviated hyperglycemia in diabetic rats primarily by modulating gut microbiota along with lessening leaky gut, leading to improvement in endotoxemia and inflammation-disturbed insulin signaling, which was mediated partly by PI3K/Akt signaling and AMPK activation.

Dietary Components, Microbial Metabolites and Human Health: Reading between the Lines

Trillions of bacteria reside in the human gut and they metabolize dietary substances to obtain nutrients and energy while producing metabolites. Therefore, different dietary components could affect human health in various ways through microbial metabolism. Many such metabolites have been shown to affect human physiological activities, including short-chain fatty acids metabolized from carbohydrates; indole, kynurenic acid and para-cresol, metabolized from amino acids; conjugated linoleic acid and linoleic acid, metabolized from lipids. Here, we review the features of these metabolites and summarize the possible molecular mechanisms of their metabolisms by gut microbiota. We discuss the potential roles of these metabolites in health and diseases, and the interactions between host metabolism and the gut microbiota. We also show some of the major dietary patterns around the world and hope this review can provide insights into our eating habits and improve consumers' health conditions.

Human microbiota-transplanted C57BL/6 mice and offspring display reduced establishment of key bacteria and reduced immune stimulation compared to mouse microbiota-transplantation

Transplantation of germ-free (GF) mice with microbiota from mice or humans stimulates the intestinal immune system in disparate ways. We transplanted a human microbiota into GF C57BL/6 mice and a murine C57BL/6 microbiota into GF C57BL/6 mice and Swiss-Webster (SW) mice. Mice were bred to produce an offspring generation. 56% of the Operational Taxonomic Units (OTUs) present in the human donor microbiota established in the recipient mice, whereas 81% of the C57BL/6 OTUs established in the recipient C57BL/6 and SW mice. Anti-inflammatory bacteria such as Faecalibacterium and Bifidobacterium from humans were not transferred to mice. Expression of immune-related intestinal genes was lower in human microbiota-mice and not different between parent and offspring generation. Expression of intestinal barrier-related genes was slightly higher in human microbiota-mice. Cytokines and chemokines measured in plasma were differentially present in human and mouse microbiota-mice. Minor differences in microbiota and gene expression were found between transplanted mice of different genetics. It is concluded that important immune-regulating bacteria are lost when transplanting microbiota from humans to C57BL/6 mice, and that the established human microbiota is a weak stimulator of the murine immune system. The results are important for study design considerations in microbiota transplantation studies involving immunological parameters.

Short-Term Amoxicillin-Induced Perturbation of the Gut Microbiota Promotes Acute Intestinal Immune Regulation in Brown Norway Rats

The intestinal gut microbiota is essential for maintaining host health. Concerns have been raised about the possible connection between antibiotic use, causing microbiota disturbances, and the increase in allergic and autoimmune diseases observed during the last decades. To elucidate the putative connection between antibiotic use and immune regulation, we have assessed the effects of the antibiotic amoxicillin on immune regulation, protein uptake, and bacterial community structure in a Brown Norway rat model. Daily intra-gastric administration of amoxicillin resulted in an immediate and dramatic shift in fecal microbiota, characterized by a reduction of within sample (α) diversity, reduced variation between animals (β diversity), increased relative abundance of Bacteroidetes and Gammaproteobacteria, with concurrent reduction of Firmicutes, compared to a water control group. In the small intestine, amoxicillin also affected microbiota composition significantly, but in a different way than observed in feces. The small intestine of control animals was vastly dominated by Lactobacillus, but this genus was much less abundant in the amoxicillin group. Instead, multiple different genera expanded after amoxicillin administration, with high variation between individual animals, thus the small intestinal α and β diversity were higher in the amoxicillin group compared to controls. After 1 week of daily amoxicillin administration, total fecal IgA level, relative abundance of small intestinal regulatory T cells and goblet cell numbers were higher in the amoxicillin group compared to controls. Several bacterial genera, including Escherichia/Shigella, Klebsiella (Gammaproteobacteria), and Bifidobacterium, for which the relative abundance was higher in the small intestine in the amoxicillin group than in controls, were positively correlated with the fraction of small intestinal regulatory T cells. Despite of epidemiologic studies showing an association between early life antibiotic consumption and later prevalence of inflammatory bowel diseases and food allergies, our findings surprisingly indicated that amoxicillin-induced perturbation of the gut microbiota promotes acute immune regulation. We speculate that the observed increase in relative abundance of small intestinal regulatory T cells is partly mediated by immunomodulatory lipopolysaccharides derived from outgrowth of Gammaproteobacteria.

Xylooligosaccharide Modulates Gut Microbiota and Alleviates Colonic Inflammation Caused by High Fat Diet Induced Obesity

Obesity leads to colonic inflammation and may increase the risk of colorectal cancer. Xylooligosaccharide (XOS) exhibits strong antioxidant and excellent antibacterial properties, and can be utilized by gut microbes to maintain the ecological balance of the intestinal tract. In this study, we explored how XOS modulates the microbiota and regulates high fat diet (HFD) induced inflammation. We measured the changes in body weight and visceral coefficients in rats fed a high-fat diet. We also measured the expression levels of inflammatory factors in the plasma and colonic tissues of the rats using the enzyme-linked immunosorbent assay and real-time quantitative polymerase chain reaction. We analyzed the composition of fecal microorganisms and short chain fatty acid (SCFA) content using 16S rDNA and GC-MS. We found that XOS significantly counteracted HFD induced weight gain. Moreover, the plasma levels of monocyte chemoattractant protein-1, tumor necrosis factor (TNF-α) and lipopolysaccharide decreased in the XOS-treated rats. XOS treatment decreased TNF-α mRNA expression and increased occludin mRNA expression in the rat colon. We observed a reduction in the overall microbial abundance in the feces of the XOS-treated rats, although the proportion of Bacteroidetes/Firmicutes increased significantly and the number of beneficial bacteria increased in the form of dominant microbes. We found that both SCFA-producing bacteria and SCFA content increased in the gut of the XOS-treated rats. We identified a correlation between the abundance of Prevotella and Paraprevotella and SCFA content. Taken together, we propose that XOS can alleviate colonic inflammation by regulating gut microbial composition and enhancing SCFA content in the gut.

Dietary xylo-oligosaccharide improves intestinal functions in weaned piglets

This study aimed at investigating the effects of dietary xylo-oligosaccharide (XOS) on intestinal functions (i.e., intestinal morphology, tight junctions, gut microbiota and metabolism) and growth performance in weaned piglets. 19 weaned piglets were randomly divided into two groups (n = 9/10): a control group (basic diet) and a XOS treated group in which piglets were fed 0.01% XOS for 28 days. Growth performance, blood cells and biochemical parameters, serum cytokines, intestinal morphology, tight junctions, gut microbiota, and the metabolic profiles of the gut digesta were analyzed. The results showed that dietary supplementation with XOS had little effects on growth performance, blood cells and biochemical parameters, and intestinal morphology. However, the inflammatory status and intestinal barrier were improved in XOS-fed piglets evidenced by the reduction of IFN-γ and upregulation of ZO-1. Microbiota analysis showed that XOS enhanced α-diversity and affected the relative abundances of Lactobacillus, Streptococcus, and Turicibacter at the genus level. The alterations in the microbiota might be further involved in carbohydrate metabolism, cell motility, cellular processes and signaling, lipid metabolism, and metabolism of other amino acids by functional prediction. A metabolomics study identified three differentiated metabolites, including coenzyme Q6, zizyphine A, and pentadecanal, which might be produced by the microbiota and further affect host metabolism. In conclusion, dietary XOS improved the inflammatory status, gut barrier, and microbiota communities, which might be used as a potential feed additive to prevent gut dysfunction caused by weaning in the pig industry.

Antihyperglycemic effect of rice husk derived xylooligosaccharides in high-fat diet and low-dose streptozotocin-induced type 2 diabetic rat model

Rice husk (RH) is an agricultural waste obtained from rice milling process. Our previous study demonstrated the optimized process of extracting xylooligosaccharides (XOS), a prebiotic that can support the growth and activity of beneficial gut microbiota, from RH. Accumulated evidences indicate that the composition of gut microbiota is involved in the progression of insulin resistance and diabetes. This study aims to evaluate the antihyperglycemic effect and putative mechanisms of RH-XOS using a diabetic rat model induced by high-fat diet and streptozotocin injection. Diabetic rats were randomly assigned to receive vehicle (DMC), XOS (DM-XOS), metformin (DMM), and a combination of XOS and metformin (DMM-XOS). An additional group of rats were fed with normal diet plus vehicle (NDC) and normal diet plus XOS (ND-XOS). Supplementation with RH-XOS for 12 weeks successfully decreased the fasting plasma glucose, insulin, leptin, and LPS levels in DM-XOS compared with DMC. Likewise, the insulin-stimulated glucose uptake assessed by in vitro study was significantly enhanced in DM-XOS, DMM, and DMM-XOS. The diminished protein expressions of GLUT4 and pAktSer473 as well as pAMPKThr172 were significantly modulated in DM-XOS, DMM, and DMM-XOS groups. Interestingly, RH-XOS supplementation reversed the changed gut permeability, elevated the number of beneficial bacteria, both Lactobacillus and Bifidobacterium spp., and increased SCFAs production. Taken together, the results confirm the efficacy of RH-XOS in achieving good glycemic control in diabetes by maintenance of gut microbiota and attenuation of endotoxemia. The findings reveal the benefits of RH-XOS and open an opportunity to improve its value by its development as a nutraceutical for diabetes.

Synbiotic supplementation containing Bifidobacterium infantis and xylooligosaccharides alleviates dextran sulfate sodium-induced ulcerative colitis

Synbiotics (Bifidobacterium infantis + xylooligosaccharides) had the strongest efficacy on colitis through inhibiting inflammation and oxidative stress and protecting epithelial integrity.

Food Supplements to Mitigate Detrimental Effects of Pelvic Radiotherapy

Pelvic radiotherapy has been frequently reported to cause acute and late onset gastrointestinal (GI) toxicities associated with significant morbidity and mortality. Although the underlying mechanisms of pelvic radiation-induced GI toxicity are poorly understood, they are known to involve a complex interplay between all cell types comprising the intestinal wall. Furthermore, increasing evidence states that the human gut microbiome plays a role in the development of radiation-induced health damaging effects. Gut microbial dysbiosis leads to diarrhea and fatigue in half of the patients. As a result, reinforcement of the microbiome has become a hot topic in various medical disciplines. To counteract GI radiotoxicities, apart from traditional pharmacological compounds, adjuvant therapies are being developed including food supplements like vitamins, prebiotics, and probiotics. Despite the easy, cheap, safe, and feasible approach to protect patients against acute radiation-induced toxicity, clinical trials have yielded contradictory results. In this review, a detailed overview is given of the various clinical, intestinal manifestations after pelvic irradiation as well as the role of the gut microbiome herein. Furthermore, whilst discussing possible strategies to prevent these symptoms, food supplements are presented as auspicious, prophylactic, and therapeutic options to mitigate acute pelvic radiation-induced GI injury by exploring their molecular mechanisms of action.

Modulation of microbial communities and mucosal gene expression in chicken intestines after galactooligosaccharides delivery In Ovo

Intestinal mucosa is the interface between the microbial content of the gut and the host's milieu. The goal of this study was to modulate chicken intestinal microflora by in ovo stimulation with galactooligosaccharides (GOS) prebiotic and to demonstrate the molecular responses of the host. The animal trial was performed on meat-type chickens (Ross 308). GOS was delivered by in ovo injection performed into the air cell on day 12 of egg incubation. Analysis of microbial communities and mucosal gene expression was performed at slaughter (day 42 post-hatching). Chyme (for DNA isolation) and intestinal mucosa (for RNA isolation) from four distinct intestinal segments (duodenum, jejunum, ileum, and caecum) was sampled. The relative abundance of Bifidobacterium spp. and Lactobacillus spp. in DNA isolated from chyme samples was determined using qPCR. On the host side, the mRNA expression of 13 genes grouped into two panels was analysed with RT-qPCR. Panel (1) included genes related to intestinal innate immune responses (IL-1β, IL-10 and IL-12p40, AvBD1 and CATHL2). Panel (2) contained genes involved in intestinal barrier function (MUC6, CLDN1 and TJAP1) and nutrients sensing (FFAR2 and FFAR4, GLUT1, GLUT2 and GLUT5). GOS increased the relative abundance of Bifidobacterium in caecum (from 1.3% to 3.9%). Distinct effects of GOS on gene expression were manifested in jejunum and caecum. Cytokine genes (IL-1β, IL-10 and IL-12p40) were up-regulated in the jejunum and caecum of the GOS-treated group. Host defence peptides (AvBD1 and CATHL2) were up-regulated in the caecum of the GOS-treated group. Free fatty acid receptors (FFAR2 and FFAR4) were up-regulated in all three compartments of the intestine (except the duodenum). Glucose transporters were down-regulated in duodenum (GLUT2 and GLUT5) but up-regulated in the hindgut (GLUT1 and GLUT2). In conclusion, GOS delivered in ovo had a bifidogenic effect in adult chickens. It also modulated gene expression related to intestinal immune responses, gut barrier function, and nutrient sensing.

Prebiotic compounds from agro-industrial by-products

Prebiotics are nondigestible food components that have an impact on gut microbiota composition and activity, which in turn results in the improvement of health conditions. Nowadays, the production of prebiotics from agro-industrial by-products is under investigation. In this regard, polysaccharides are usually found in these sources and their potential use as prebiotics has been studied recently since these compounds act as substrates for the human gut microbiota, and they have the potential to modulate its composition through many mechanisms. Additionally, the use of agricultural by-products is advantageous because it is a cheap and abundantly available material. This review focuses on the recent scientific literature regarding the prebiotic properties of polysaccharides from agro-industrial by-products. PRACTICAL APPLICATIONS: Currently, the maintenance of gut homeostasis is a target for the improvement of human health. This review can broaden the perspective on the utilization of agro-industrial by-products that can compete in the market with the commercial ones or act as a source for new food ingredients.

Prebiotic prevents impaired kidney and renal Oat3 functions in obese rats

Obesity is health issue worldwide, which can lead to kidney dysfunction. Prebiotics are non-digestible foods that have beneficial effects on health. This study aimed to investigate the effects of xylooligosaccharide (XOS) on renal function, renal organic anion transporter 3 (Oat3) and the mechanisms involved. High-fat diet was provided for 12 weeks in male Wistar rats. After that, the rats were divided into normal diet (ND); normal diet treated with XOS (NDX); high-fat diet (HF) and high-fat diet treated with XOS (HFX). XOS was given daily at a dose of 1000 mg for 12 weeks. At week 24, HF rats showed a significant increase in obesity and insulin resistance associated with podocyte injury, increased microalbuminuria, decreased creatinine clearance and impaired Oat3 function. These alterations were improved by XOS supplementation. Renal MDA level and the expression of AT1R, NOX4, p67^phox, 4-HNE, phosphorylated PKCα and ERK1/2 were significantly decreased after XOS treatment. In addition, Nrf2-Keap1 pathway, SOD2 and GCLC expression as well as renal apoptosis were also significantly reduced by XOS. These data suggest that XOS could indirectly restore renal function and Oat3 function via the reduction of oxidative stress and apoptosis through the modulating of AT1R-PKCα-NOXs activation in obese insulin-resistant rats. These attenuations were instigated by the improvement of obesity, hyperlipidemia and insulin resistance.