Effects of pectin supplementation on the fermentation patterns of different structural carbohydrates in rats

Effects of pectin methyl-esterification on intestinal microbiota and its immunomodulatory properties in naive mice

Pectins are dietary fibers that are attributed with several beneficial immunomodulatory effects. Depending on the degree of esterification (DE), pectins can be classified as high methoxyl pectin (HMP) or low methoxyl pectin (LMP). The aim of this study was to investigate the effects of pectin methyl-esterification on intestinal microbiota and its immunomodulatory properties in naive mice. Supplementation of the diet with LMP or HMP induced changes in the composition of the intestinal microbiota in mice toward Bacteroides, which was mainly promoted by HMP. Metabolome analysis of stool samples from pectin-fed mice showed a different effect of the two types of pectin on the levels of short-chain fatty acids and bile acids, which was consistent with highly efficient in vivo fermentation of LMP. Analysis of serum antibody levels showed a significant increase in IgG and IgA levels by both pectins, while FACS analysis revealed a decrease of infiltrating inflammatory cells in the intestinal lamina propria by HMP. Our study revealed that the structural properties of the investigated pectins determine fermentability, effects on microbial composition, metabolite production, and modulation of immune responses. Consumption of HMP preferentially altered the gut microbiota and suppressed pro-inflammatory immune responses, suggesting a beneficial role in inflammatory diseases.

A methyl esterase from Bifidobacterium longum subsp. longum reshapes the prebiotic properties of apple pectin by triggering differential modulatory capacity in faecal cultures

Pectin structures have received increasing attention as emergent prebiotics due to their capacity to promote beneficial intestinal bacteria. Yet the collective activity of gut bacterial communities to cooperatively metabolize structural variants of this substrate remains largely unknown. Herein, the characterization of a pectin methylesterase, BpeM, from Bifidobacterium longum subsp. longum, is reported. The purified enzyme was able to remove methyl groups from highly methoxylated apple pectin, and the mathematical modelling of its activity enabled to tightly control the reaction conditions to achieve predefined final degrees of methyl-esterification in the resultant pectin. Demethylated pectin, generated by BpeM, exhibited differential fermentation patterns by gut microbial communities in in vitro mixed faecal cultures, promoting a stronger increase of bacterial genera associated with beneficial effects including Lactobacillus, Bifidobacterium and Collinsella. Our findings demonstrate that controlled pectin demethylation by the action of a B. longum esterase selectively modifies its prebiotic fermentation pattern, producing substrates that promote targeted bacterial groups more efficiently. This opens new possibilities to exploit biotechnological applications of enzymes from gut commensals to programme prebiotic properties.

Toxicological evaluation of a pumpkin-derived pectin preparation: in vitro genotoxicity studies and a 13-week oral toxicity study in Sprague-Dawley rats

The safety of a rhamnogalacturonan-I-enriched pectin extract (G3P-01) from pumpkin (Cucurbita moschata var. Dickinson) was evaluated for use as an ingredient in food and dietary supplements. G3P-01 was tested in a battery of genetic toxicity studies including reverse mutagenicity and in vitro micronucleus assay. In addition, Sprague-Dawley rats were randomized and orally dosed with G3P-01 incorporated in animal diet at concentrations of 0, 9000, 18,000, and 36,000 ppm daily for 13-weeks (n=10/sex/group) in line with OECD guidelines (TG 408). The results of the in vitro bacterial reverse mutation assay and micronucleus assay in TK6 cells demonstrated a lack of genotoxicity. The 13-week oral toxicity study in Sprague-Dawley rats demonstrated that the test article, G3P-01 was well tolerated; there were no mortalities and no adverse effects on clinical, gross pathology, hematology, blood chemistry, and histological evaluation of the essential organs of the animals. The present study demonstrates that G3P-01 is non-genotoxic and is safe when ingested in diet at concentrations up to 36, 000 ppm. The subchronic no-observed-adverse-effect level (NOAEL) for G3P-01 was concluded to be 36,000 ppm, equivalent to 1,899 and 2,361 mg/kg/day for male and female rats respectively.

New insight into pectic fractions of cell wall: Impact of extraction on pectin structure and in vitro gut fermentation

Pectic polysaccharides modulate gut fermentation ability, which is determined by structural characteristics. In this work, apple pectins were extracted by HCl (HAEP), NaOH (AEP), cellulase (EAEP), and in parallel cell wall pectic fractions were sequentially extracted by water (WEP), chelator (CEP) and NaOH (NEP). The aim is to comprehensively compare the impact of extraction on pectin structure and gut fermentation behavior. Results showed that high content of galacturonic acid (90.65 mol%) and large molecular weight (675 kg/mol) were detected in the HAEP. Molecular morphology of the HAEP presented high linearity, while AEP, EAEP and WEP exhibited compact filamentous structures with highly branched patterns. The AEP was characterized by high yield (33.1 g/100 g d.b.), moderate molecular weight (304 kg/mol) and large extent of rhamnogalacturonan-I region (24.88 %) with low degree of branching (1.77). After in vitro simulated gut fermentation for 24 h, total content of short-chain fatty acid (SCFA) generated with the AEP supplement increased to 36.8 mmol/L, followed by EAEP, HAEP and WEP (25.2, 24.2 and 20.3 mmol/L, respectively). Meanwhile, WEP simultaneously produced the highest ammonia content (22.4 mmol/L). This investigation suggests that the fermentation of AEP produces more beneficial SCFA and less ammonia, thus indicating a better gut fermentation property.

Pectin Modulates Calcium Absorption in Polarized Caco-2 Cells via a Pathway Distinct from Vitamin D Stimulation

Pectin, a type of soluble fiber, promotes morphological changes in the small intestinal villi. Although its physiological significance is unknown, we hypothesized that changes in villus morphology enhance the efficiency of nutrient absorption in the small intestine and investigated the effect of pectin derived from persimmon on calcium absorption using polarized Caco-2 cells. In polarized Caco-2 cells, pectin altered the mRNA expression levels of substances involved in calcium absorption and the regulation of intracellular calcium concentration and significantly reduced calcium absorption. Although this was comparable to the results of absorption and permeability associated with the addition of active vitamin D, the simultaneous action of pectin and active vitamin D did not show any additive effects. Furthermore, as active vitamin D significantly increases the activity of intestinal alkaline phosphatase (ALP), which is known to be involved in the regulation of intestinal absorption of calcium and lipids, we also investigated the effect of pectin on intestinal ALP activity. As a result, it was found that, unlike the effect of active vitamin D, pectin significantly reduced intestinal ALP activity. These results suggest that pectin stimulates polarized Caco-2 cells through a mechanism distinct from the regulation of calcium absorption by vitamin D, modulating total calcium absorption from the elongated villi through morphological changes in the small intestine by suppressing it at the cellular level.

Lutein combined with EGCG improved retinitis pigmentosa against N-methyl-N nitrosourea-induced

In order to investigate the synergistic improving effect of lutein (LUT) and epigallocatechin-3-gallate (EGCG) treatment on retinitis pigmentosa (RP), an N-methyl-N-nitrosourea (MNU)-induced mouse model was conducted in the present study. Compared to the LUT alone treatment group, in the LUT combined with EGCG (LUT-EGCG) treatment group, the accumulation content of LUT was significantly increased by 50.24% in the liver. The morphological results indicated that LUT-EGCG treatment significantly improved the retina structure with the thickness of the outer nuclear layer restored to 185.28 ± 0.29 μm, showing no significant difference compared to the control group. The LUT-EGCG treatment also increased the production of short-chain fatty acids, such as acetic and propionic acids. Compared with the LUT alone treatment, the LUT-EGCG treatment significantly increased the relative abundance of Lachnospiraceae and Helicobacteraceae. RT-qPCR results indicated that LUT-EGCG treatment significantly increased the antiapoptotic gene Bcl-2 expression. In addition, the expression of IL-6 was significantly down-regulated in the LUT-EGCG group, while there was no significance in NF-κβ, TNF-α, IL-1β, and IL-18 compared with the LUT group. Correlation analysis supported the conclusion that LUT combined with EGCG may improve RP by modulating antiapoptotic gene expression and regulating the abundance of gut microbiota. However, the underlying mechanism still needs further research.

Fermentation patterns of prebiotics fructooligosaccharides-SCFA esters inoculated with fecal microbiota from ulcerative colitis patients

Ulcerative colitis (UC) is believed to arise from an imbalance between the intestinal microbiota and mucosal immunity, leading to excessive intestinal inflammation. Modulating the gut microbial community through dietary components presents a valuable strategy in aiding the treatment of UC. In this study, esters formed by binding of well-known prebiotics, fructooligosaccharides (FOS), with short chain fatty acids (SCFAs) via both enzymatic and chemical methods were evaluated for their impact on the gut microbiota of UC patients. An in vitro human colonic fermentation model was employed to monitor changes in total carbohydrates and SCFAs production during the fermentation of these esters by microbiota from patients with active and remission UC. The results showed that pronounced abundance of [Ruminococcus]_gnavus_group, Escherichia_Shigella, Lachnoclostridium, Klebsiella and other potential pathogens were detected in the fecal samples from UC patients, with a milder condition observed during the remission phase. Significant higher levels of corresponding SCFA were observed in the groups with addition of FOS-SCFAs esters during fermentation. Butyrylated fructooligosaccharides (B-FOS) and propionylated fructooligosaccharides (P-FOS) by enzymatic synthesis successfully promoted the proliferation of Bifidobacterium and inhibited Clostridium_sensu_stricto_1 and Klebsiella. Overall, B-FOS and P-FOS exhibit promising potential for restoring intestinal homeostasis and alleviating intestinal inflammation in individuals with UC.

Recent progress in plant-derived polysaccharides with prebiotic potential for intestinal health by targeting gut microbiota: a review

Natural products of plant origin are of high interest and widely used, especially in the food industry, due to their low toxicity and wide range of bioactive properties. Compared to other plant components, the safety of polysaccharides has been generally recognized. As dietary fibers, plant-derived polysaccharides are mostly degraded in the intestine by polysaccharide-degrading enzymes secreted by gut microbiota, and have potential prebiotic activity in both non-disease and disease states, which should not be overlooked, especially in terms of their involvement in the treatment of intestinal diseases and the promotion of intestinal health. This review elucidates the regulatory effects of plant-derived polysaccharides on gut microbiota and summarizes the mechanisms involved in targeting gut microbiota for the treatment of intestinal diseases. Further, the structure-activity relationships between different structural types of plant-derived polysaccharides and the occurrence of their prebiotic activity are further explored. Finally, the practical applications of plant-derived polysaccharides in food production and food packaging are summarized and discussed, providing important references for expanding the application of plant-derived polysaccharides in the food industry or developing functional dietary supplements.

Structural characteristics and in vitro fermentation patterns of polysaccharides from Boletus mushrooms

The aim of this study was to investigate the structural characteristics and in vitro fermentation patterns of polysaccharides from Boletus mushrooms. Polysaccharides were solubilized from fruit bodies of selected mushrooms Boletus auripes, B. bicolor, and B. griseus using subcritical water extraction. Boletus polysaccharides were characterized for their general physicochemical pattern, constituent monosaccharides and molecular weight. A simulated in vitro fermentation model was used to study the utilization of Boletus polysaccharides by the gut microbiota and their consequent modulation of microbial communities. Results showed that the main constituent monosaccharides of Boletus polysaccharides were glucose, galactose and mannose, followed by fucose, xylose and rhamnose, with glucose being the most abundant. The polysaccharides from B. bicolor and B. griseus exhibited a relatively high proportion of galactose and mannose, respectively. Boletus polysaccharides exhibited a wide range of molecular weights (5 kDa to 2000 kDa), which covered multiple polysaccharide populations, but the proportions of these populations varied among the samples. Boletus polysaccharides were gradually utilized by the human fecal microbiota, promoting the production of SCFAs. Boletus polysaccharides contributed to a healthier gut microbiota composition by increasing the relative abundance of beneficial bacterial genera such as Bacteroides and Faecalibacterium and reducing the relative abundance of harmful bacterial genera such as Sutterella and Escherichia-Shigella. B. bicolor polysaccharides showed better fermentability and prebiotic effects than the other Boletus polysaccharide groups. Therefore, the consumption of select Boletus mushrooms, particularly B. bicolor, could be a potential approach to obtain polysaccharides for microbiota modulation and to support gut health.

Spectroscopic Analyses Highlight Plant Biostimulant Effects of Baker's Yeast Vinasse and Selenium on Cabbage through Foliar Fertilization

The main aim of this study is to find relevant analytic fingerprints for plants' structural characterization using spectroscopic techniques and thermogravimetric analyses (TGAs) as alternative methods, particularized on cabbage treated with selenium-baker's yeast vinasse formulation (Se-VF) included in a foliar fertilizer formula. The hypothesis investigated is that Se-VF will induce significant structural changes compared with the control, analytically confirming the biofortification of selenium-enriched cabbage as a nutritive vegetable, and particularly the plant biostimulant effects of the applied Se-VF formulation on cabbage grown in the field. The TGA evidenced a structural transformation of the molecular building blocks in the treated cabbage leaves. The ash residues increased after treatment, suggesting increased mineral accumulation in leaves. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) evidenced a pectin-Iα-cellulose structure of cabbage that correlated with each other in terms of leaf crystallinity. FTIR analysis suggested the accumulation of unesterified pectin and possibly (seleno) glucosinolates and an increased network of hydrogen bonds. The treatment with Se-VF formulation induced a significant increase in the soluble fibers of the inner leaves, accompanied by a decrease in the insoluble fibers. The ratio of soluble/insoluble fibers correlated with the crystallinity determined by XRD and with the FTIR data. The employed analytic techniques can find practical applications as fast methods in studies of the effects of new agrotechnical practices, while in our particular case study, they revealed effects specific to plant biostimulants of the Se-VF formulation treatment: enhanced mineral utilization and improved quality traits.

Effects of Modified Dietary Fiber from Fresh Corn Bracts on Obesity and Intestinal Microbiota in High-Fat-Diet Mice

The effects of insoluble dietary fiber from fresh corn bracts modified by dynamic high-pressure micro-fluidization (DHPM) on the pathological characteristics of obesity, intestinal microflora distribution and production of short-chain fatty acids in high-fat-diet C57BL/6 mice were evaluated. The results show that the DHPM-modified dietary fiber from fresh corn bracts significantly reduces weight gain, insulin resistance and oxidative damage caused by a high-fat diet, and promotes the production of SCFAs, especially acetic acid, propionic acid and butyric acid. These modified dietary fibers also change the proportion of different types of bacteria in the intestinal microflora of mice, reduce the ratio of Firmicutes and Bacteroidota and promote the proliferation of Bifidobacteriales. Therefore, the DHPM-modified dietary fiber from fresh corn bracts can be used as a good intestinal microbiota regulator to promote intestinal health, thereby achieving the role of preventing and treating obesity.

Different Approaches to Ergogenic, Pre-, and Probiotic Supplementation in Sports with Different Metabolism Characteristics: A Mini Review

Sport disciplines with different metabolic characteristics require different dietary approaches. Bodybuilders or sprinters ("anaerobic" athletes) need a high-protein diet (HPD) in order to activate muscle protein synthesis after exercise-induced muscle damage and use nitric oxide enhancers (such as citrulline and nitrates) to increase vasodilatation, whereas endurance athletes, such as runners or cyclists ("aerobic" athletes), prefer a high-carbohydrate diet (HCHD), which aims to restore the intramuscular glycogen, and supplements containing buffering agents (such as sodium bicarbonate and beta-alanine). In both cases, nutrient absorption, neurotransmitter and immune cell production and muscle recovery depend on gut bacteria and their metabolites. However, there is still insufficient data on the impact of an HPD or HCHD in addition to supplements on "anaerobic" and "aerobic" athletes' gut microbiota and how this impact could be affected by nutritional interventions such as pre- and probiotic therapy. Additionally, little is known about the role of probiotics in the ergogenic effects of supplements. Based on the results of our previous research on an HPD in amateur bodybuilders and an HCHD in amateur cyclists, we reviewed human and animal studies on the effects of popular supplements on gut homeostasis and sport performance.

Effects of in vitro simulated digestion and fecal fermentation of polysaccharides from straw mushroom (Volvariella volvacea) on its physicochemical properties and human gut microbiota

Herein, the fermentation and digestion behavior of Volvariella volvacea polysaccharide (VVP) were examined through the in vitro simulation experiment. The results revealed that succeeding the simulated salivary gastrointestinal digestion, the molecular weight of VVP was reduced by only 8.9 %. In addition, the reducing sugar, uronic acid, monosaccharide composition and Fourier transform infrared spectroscopy characteristics of VVP did not change significantly, which indicate that saliva-gastrointestinal could not digest VVP. However, 48 h of fecal fermentation of VVP dramatically reduced its molecular weight by 40.4 %. Furthermore, the molar ratios of the monosaccharide composition altered considerably due to the degradation of VVP by microorganisms and the metabolysis into different short-chain fatty acids (SCFAs). Meanwhile, the VVP also raised the proportion of Bacteroidetes to Firmicutes and promoted the proliferation of some beneficial bacteria including Bacteroides and Phascolarctobacterium, whereas it inhibited the growth of unfavorable bacteria such as Escherichia-shigella. Therefore, VVP has the potential to have a positive influence on health and hinder diseases by improving the intestinal microbial environment. These findings provide a theoretical foundation to further develop Volvariella volvacea as a healthy functional food.

The Preparation and Potential Bioactivities of Modified Pectins: A Review

Pectins are complex polysaccharides that are widely found in plant cells and have a variety of bioactivities. However, the high molecular weights (M_w) and complex structures of natural pectins mean that they are difficult for organisms to absorb and utilize, limiting their beneficial effects. The modification of pectins is considered to be an effective method for improving the structural characteristics and promoting the bioactivities of pectins, and even adding new bioactivities to natural pectins. This article reviews the modification methods, including chemical, physical, and enzymatic methods, for natural pectins from the perspective of their basic information, influencing factors, and product identification. Furthermore, the changes caused by modifications to the bioactivities of pectins are elucidated, including their anti-coagulant, anti-oxidant, anti-tumor, immunomodulatory, anti-inflammatory, hypoglycemic, and anti-bacterial activities and the ability to regulate the intestinal environment. Finally, suggestions and perspectives regarding the development of pectin modification are provided.

Pectin mediates the mechanism of host blood glucose regulation through intestinal flora

Pectin is a complex polysaccharide found in plant cell walls and interlayers. As a food component, pectin is benefit for regulating intestinal flora. Metabolites of intestinal flora, including short-chain fatty acids (SCFAs), bile acids (BAs) and lipopolysaccharides (LPS), are involved in blood glucose regulation. SCFAs promote insulin synthesis through the intestine-GPCRs-derived pathway and hepatic adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) pathway to promote hepatic glycogen synthesis. On the one hand, BAs stimulate intestinal L cells and pancreatic α cells to secrete Glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) through receptors G protein-coupled receptor (TGR5) and farnesoid X receptor (FXR). On the other hand, BAs promote hepatic glycogen synthesis through AMPK pathway. LPS inhibits the release of inflammatory cytokines through Toll-like receptors (TLRs)-myeloid differentiation factor 88 (MYD88) pathway and mitogen-activated protein kinase (MAPK) pathway, thereby alleviating insulin resistance (IR). In brief, both SCFAs and BAs promote GLP-1 secretion through different pathways, employing strategies of increasing glucose consumption and decreasing glucose production to maintain normal glucose levels. Notably, pectin can also directly inhibit the release of inflammatory cytokines through the -TLRs-MYD88 pathway. These data provide valuable information for further elucidating the relationship between pectin-intestinal flora-glucose metabolism.

Serum short chain fatty acids mediate hippocampal BDNF and correlate with decreasing neuroinflammation following high pectin fiber diet in mice

Introduction

Dietary components, such as prebiotic fiber, are known to impact brain chemistry via the gut-brain axis. In particular, short chain fatty acids (SCFAs) generated from excessive soluble fiber consumption are thought to impact neuroimmune signaling and brain function through increased production of neurotropic factors. Given reports that high dietary fiber intake is associated with increased mental health and improved quality of life scores, we set out to identify whether changes in SCFA levels as a result of a high soluble fiber diet mediate hippocampal neuroinflammation and brain derived neurotrophic factor (BDNF) in mice.

Methods

Adult male and female C57BL/6 mice were fed a 1-month high pectin fiber or cellulose-based control diet. Following 1 month of excessive pectin consumption, serum SCFAs were measured using gas chromatography-mass spectrometry (GC-MS) and hippocampal cytokines and BDNF were assessed via multiplex magnetic bead immunoassay.

Results

Pectin-based fiber diet increased circulating acetic acid in both sexes, with no effect on propionic or butyric acid. In the hippocampus, a high fiber diet decreased TNFa, IL-1ß, IL-6, and IFNγ and increased BDNF levels. Furthermore, increased SCFA levels were inversely correlated with neuroinflammation in the hippocampus, with acetic acid revealed as a strong mediator of increased BDNF production.

Conclusion

Collectively, these findings highlight the beneficial effects of fiber-induced molecular changes in a brain region known to influence mood- and cognition-related behaviors. Dietary composition should be considered when developing mental health management plans for men and women with an emphasis on increasing soluble fiber intake.

Pectin in Metabolic Liver Disease

Alterations in the composition of the gut microbiota (dysbiosis) are observed in nutritional liver diseases, including non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) and have been shown to be associated with the severity of both. Editing the composition of the microbiota by fecal microbiota transfer or by application of probiotics or prebiotics/fiber in rodent models and human proof-of-concept trials of NAFLD and ALD have demonstrated its possible contribution to reducing the progression of liver damage. In this review, we address the role of a soluble fiber, pectin, in reducing the development of liver injury in NAFLD and ALD through its impact on gut bacteria.

Mechanistic Understanding of the Effects of Pectin on In Vivo Starch Digestion: A Review

Obesity and type II diabetes are closely related to the rapid digestion of starch. Starch is the major food-energy source for most humans, and thus knowledge about the regulation of starch digestion can contribute to prevention and improved treatment of carbohydrate metabolic disorders such as diabetes. Pectins are plant polysaccharides with complex molecular structures and ubiquitous presence in food, and have diverse effects on starch digestion. Pectins can favorably regulate in vivo starch digestion and blood glucose level responses, and these effects are attributed to several reasons: increasing the viscosity of digesta, inhibiting amylase activity, and regulating some in vivo physiological responses. Pectins can influence starch digestion via multiple mechanisms simultaneously, in ways that are highly structure-dependent. Utilizing the multi-functionalities of pectin could provide more ways to design low glycemic-response food and while avoiding the unpalatable high viscosity in food by which is commonly caused by many other dietary fibers.

Study on the Interaction between Four Typical Carotenoids and Human Gut Microflora Using an in Vitro Fermentation Model

Recent studies indicated a strong relationship between carotenoids and gut microflora. However, their structure-activity relationship remains unclear. This study evaluated the interaction between four typical carotenoids (β-carotene, lutein, lycopene, and astaxanthin) and gut microflora using an in vitro fermentation model. After 24 h of fermentation, the retention rates of the four carotenoids were 1.40, 1.38, 1.46, and 5.63 times lower than those of their without gut microflora control groups, respectively. All four carotenoid treated groups significantly increased total short-chain fatty acids (SCFAs) production. All carotenoid supplements significantly promoted the abundance of Roseburia and Parasutterella and inhibited the abundance of Collinsella, while β-carotene, lutein, lycopene, and astaxanthin significantly promoted the abundance of Ruminococcus, Sutterella, Subdoligranulum, and Megamonas, respectively. Furthermore, xanthophylls have a more significant impact on gut microflora than carotenes. This study provides a new way to understand how carotenoids work in the human body with the existing gut microflora.

Tumor Microenvironment Multiple Responsive Nanoparticles for Targeted Delivery of Doxorubicin and CpG Against Triple-Negative Breast Cancer

Introduction

Currently, the main treatment for advanced breast cancer is still chemotherapy. Immunological and chemical combination therapy has a coordinated therapeutic effect and achieves some efficacy. However, the immunosuppressive tumor microenvironment is a major cause for the failure of immunotherapy in breast cancer. CpG oligodeoxynucleotides can activate the tumor immune microenvironment to reverse the failure of immunotherapy.

Methods

In this study, we designed an amphiphilic peptide micelle system (Co-LMs), which can targeted delivery of the immune adjuvant CpG and the chemotherapeutic drug doxorubicin to breast cancer tumors simultaneously. The peptide micelle system achieved tumor microenvironment pH and redox-sensitive drug release.

Results and Discussion

Co-LMs showed 2.3 times the antitumor efficacy of chemotherapy alone and 5.1 times the antitumor efficacy of immunotherapy alone in triple-negative breast cancer mice. Co-LMs activated cytotoxic CD8+ T lymphocytes and CD4+ T cells in mice to a greater extent than single treatments. We also found that Co-LMs inhibited the metastasis of circulating tumor cells in the bloodstream to some extent. These results indicate that the Co-LMs offer a promising therapeutic strategy against triple-negative breast cancer.

Dietary citrus pectin drives more ileal microbial protein metabolism and stronger fecal carbohydrate fermentation over fructo-oligosaccharide in growing pigs

Fructo-oligosaccharide (FOS) and pectin are known soluble dietary fibers and can influence gut microbiota and consequently modulate gut health. To understand the differential impact patterns of pectin vs. FOS in modulating gut microbiota in the small and large intestine, an ileal-cannulated pig model was adopted to compare the temporal and spatial effects of FOS and citrus pectin (CP) on the gut microbiota. Sixteen terminal ileal-cannulated pigs were randomly divided into 2 groups and fed with a standard diet supplemented with either 3% FOS or 3% CP for 28 d. The CP group and FOS group showed different microbial composition, especially in the feces, with time and location as major factors affecting microbiota in the CP group, and with only location contribution in the FOS group. In the feces, relative to the FOS group, the CP group showed higher abundance of ChristensenellaceaeR-7 group and RuminococcaceaeUCG-010 and lower abundance of Mitsuokella and Olsenella (adjusted P < 0.05), a higher level of short-chain fatty acids and a lower level of lactate at both d 14 and 25 (P < 0.05), and more copy numbers of genes encoding key enzymes related to propionate (mmdA) and butyrate (BCoAT) production and lactate utilization (LcdA) (P < 0.05), indicating a greater degree of microbial carbohydrate fermentation. In the ileum, as compared with FOS, CP increased the bacteria with high capability of fermenting amino acids, including Escherichia-Shigella and Klebsiella (adjusted P < 0.05), and the expression of enzymes responsible for amino acid fermentation (i.e. lysine decarboxylase), as well as the amino acid fermentation products (cadaverine and tyramine) (P < 0.05), indicating a greater degree of amino acid fermentation. Overall, our results highlight a differential dynamic impact of dietary CP vs. FOS on microbial composition and metabolism in the gut. The dietary CP has a stronger ability to promote microbial amino acid fermentation in the ileum and carbohydrate fermentation in the feces than FOS. These findings provide a new insight into the role of different fibers in gut nutrition and guidelines for the choice of fibers in manipulating gut health.

Exposure to Bisphenol A Caused Hepatoxicity and Intestinal Flora Disorder in Rats

Bisphenol A (BPA) is a globally utilized industrial chemical and is commonly used as a monomer of polycarbonate plastics and epoxy resins. Recent research reveals that BPA could cause potential adverse biological effects and liver dysfunction. However, the underlying mechanisms of BPA-induced hepatoxicity and gut dysbiosis remain unclear and deserve further study. In this study, male Sprague Dawley rats were exposed to different doses (0, 30, 90, and 270 mg/kg bw) of BPA by gavage for 30 days. The results showed that the high dose of BPA decreased superoxide dismutase (SOD), glutathione (GSH), and increased malondialdehyde (MDA) levels. Moreover, a high dose of BPA caused a significant increase in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C), while high-density lipoprotein cholesterol (HDL-C) was significantly decreased in BPA-treated rats. The gene expression of PGC-1α and Nrf1 were decreased in the liver of high doses of BPA-administrated rats, as well as the protein levels of SIRT1, PGC-1α, Nrf2, and TFAM. However, the protein expression of IL-1β was significantly increased in BPA-treated rats. In addition, BPA weakened the mitochondrial function of hepatocytes and promoted cell apoptosis in the liver by up-regulating the protein levels of Bax, cleaved-Caspase3, and cleaved-PARP1 while down-regulating the Bcl-2 in the liver. More importantly, a high dose of BPA caused a dramatic change in microbiota structure, as characterized at the genus level by increasing the ratio of Firmicutes to Bacteroidetes (F/B), and the relative abundance of Proteobacteria in feces, while decreasing the relative abundance of Prevotella_9 and Ruminococcaceae_UCG-014, which is positively correlated with the content of short-chain fatty acids (SCFAs). In summary, our data indicated that BPA exposure caused hepatoxicity through apoptosis and the SIRT1/PGC-1α pathway. BPA-induced intestinal flora and SCFA changes may be associated with hepatic damage. The results of this study provide a new sight for the understanding of BPA-induced hepatoxicity.

Effects of Monascus application on in vitro digestion and fermentation characteristics of fish protein

The aim of this study was to investigate the digestion and fermentation properties of fish protein fermented by Monascus. Semi-dried fish was fermented by applying Monascus purpureus Went M 3.439. Our results show that the Monascus fermentation of the fish protein enriched the free amino acids and achieved a relatively higher glutamate content than the control group. The Monascus treatment promoted the decomposition of the fish protein during in vitro digestion, reduced the ammonia and indole content and tended to increase the propionic acid content during in vitro fermentation. The Monascus treatment considerably changed the gut microbiota composition, and particularly increased the relative abundance of Parabacteroides in the in vitro fermentation model of human distal colon. Consumption of Monascus fermented fish protein could result in positive changes in fermentation metabolites and gut microbiota, which brings potential health benefits.

Current Research on the Effects of Non-Digestible Carbohydrates on Metabolic Disease

Metabolic diseases (MDs), including cardiovascular diseases (CVDs) and diabetes, occur when the body’s normal metabolic processes are disrupted. Behavioral risk factors such as obesity, physical inactivity, and dietary habits are strongly associated with a higher risk of MD. However, scientific evidence strongly suggests that balanced, healthy diets containing non-digestible carbohydrates (NDCs), such as dietary fiber and resistant starch, can reduce the risk of developing MD. In particular, major properties of NDCs, such as water retention, fecal bulking, viscosity, and fermentation in the gut, have been found to be important for reducing the risk of MD by decreasing blood glucose and lipid levels, increasing satiety and insulin sensitivity, and modifying the gut microbiome. Short chain fatty acids produced during the fermentation of NDCs in the gut are mainly responsible for improvement in MD. However, the effects of NDCs are dependent on the type, source, dose, and duration of NDC intake, and some of the mechanisms underlying the efficacy of NDCs on MD remain unclear. In this review, we briefly summarize current studies on the effects of NDCs on MD and discuss potential mechanisms that might contribute to further understanding these effects.

Structural Characterization and In Vitro Fermentation Characteristics of Enzymatically Extracted Black Mulberry Polysaccharides

In this study, we systematically investigated the structural characterization and in vitro fermentation patterns of crude black mulberry fruit polysaccharides (BMPs), either extracted by water (BMP) or by enzymatic treatment. Different enzymatic treatments were pectinase-extracted (PE)-BMP, pectin lyase-extracted (PL)-BMP, cellulase-extracted (CE)-BMP, and compound enzymes-extracted (M)-BMP (pectinase:pectin lyase:cellulase = 1:1:1). Our results show that enzymatic treatment improved the polysaccharide yield and led to a different chemical composition and structure for the polysaccharides. Change dynamics during the in vitro fermentation indicated that BMPs could indeed be degraded and consumed by human fecal microbiota and that different BMPs showed different degrees of fermentability. In addition, BMPs stimulated the growth of Bacteroidetes and Firmicutes, inhibited the growth of Fusobacteria and Proteobacteria (except for CE-BMP), and induced the production of short-chain fatty acids (SCFAs). Furthermore, we found that BMP and PL-BMP exhibited better fermentability and prebiotic potential than the other polysaccharides.

Effects of Keemun and Dianhong Black Tea in Alleviating Excess Lipid Accumulation in the Liver of Obese Mice: A Comparative Study

Schematic diagram of the effects of two black teas in alleviating excess hepatic lipid accumulation.

Bacterial diversity in different outdoor pilot plant photobioreactor types during production of the microalga Nannochloropsis sp. CCAP211/78

As large-scale outdoor production cannot be done in complete containment, cultures are (more) open for bacteria, which may affect the productivity and stability of the algae production process. We investigated the bacterial diversity in two indoor reactors and four pilot-scale outdoor reactors for the production of Nannochloropsis sp. CCAP211/78 spanning four months of operation from July to October. Illumina sequencing of 16S rRNA gene amplicons demonstrated that a wide variety of bacteria were present in all reactor types, with predominance of Bacteroidetes and Alphaproteobacteria. Bacterial communities were significantly different between all reactor types (except between the horizontal tubular reactor and the vertical tubular reactor) and also between runs in each reactor. Bacteria common to the majority of samples included one member of the Saprospiraceae family and one of the NS11-12_marine group (both Bacteroidetes). Hierarchical clustering analysis revealed two phases during the cultivation period separated by a major shift in bacterial community composition in the horizontal tubular reactor, the vertical tubular reactor and the raceway pond with a strong decrease of the Saprospiraceae and NS11-12_marine group that initially dominated the bacterial communities. Furthermore, we observed a less consistent pattern of bacterial taxa appearing in different reactors and runs, most of which belonging to the classes Deltaproteobacteria and Flavobacteriia. In addition, canonical correspondence analysis showed that the bacterial community composition was significantly correlated with the nitrate concentration. This study contributes to our understanding of bacterial diversity and composition in different types of outdoor reactors exposed to a range of dynamic biotic and abiotic factors. Key points • Reactor types had significantly different bacterial communities except HT and VT • The inoculum source and physiochemical factors together affect bacterial community • The bacterial family Saprospiraceae is positively correlated to microalgal growth.

The Complex Biological Effects of Pectin: Galectin-3 Targeting as Potential Human Health Improvement?

Galectin-3 is the only chimeric representative of the galectin family. Although galectin-3 has ubiquitous regulatory and physiological effects, there is a great number of pathological environments where galectin-3 cooperatively participates. Pectin is composed of different chemical structures, such as homogalacturonans, rhamnogalacturonans, and side chains. The study of pectin's major structural aspects is fundamental to predicting the impact of pectin on human health, especially regarding distinct molecular modulation. One of the explored pectin's biological activities is the possible galectin-3 protein regulation. The present review focuses on revealing the structure/function relationship of pectins, their fragments, and their biological effects. The discussion highlighted by this review shows different effects described within in vitro and in vivo experimental models, with interesting and sometimes contradictory results, especially regarding galectin-3 interaction. The review demonstrates that pectins are promissory food-derived molecules for different bioactive functions. However, galectin-3 inhibition by pectin had been stated in literature before, although it is not a fully understood, experimentally convincing, and commonly agreed issue. It is demonstrated that more studies focusing on structural analysis and its relation to the observed beneficial effects, as well as substantial propositions of cause and effect alongside robust data, are needed for different pectin molecules' interactions with galectin-3.

Revealing methyl-esterification patterns of pectins by enzymatic fingerprinting: Beyond the degree of blockiness

Citrus pectins were studied by enzymatic fingerprinting using a simultaneous enzyme treatment with endo-polygalacturonase (endo-PG) from Kluyveromyces fragilis and pectin lyase (PL) from Aspergillus niger to reveal the methyl-ester distribution patterns over the pectin backbone. Using HILIC-MS combined with HPAEC enabled the separation and identification of the diagnostic oligomers released. Structural information on the pectins was provided by using novel descriptive parameters such as degree of blockiness of methyl-esterified oligomers by PG (DB_PGme) and degree of blockiness of methyl-esterified oligomers by PL (DB_PLme). This approach enabled us to clearly differentiate citrus pectins with various methyl-esterification patterns. The simultaneous use of PG and PL showed additional information, which is not revealed in digests using PG or PL alone. This approach can be valuable to differentiate pectins having the same DM and to get specific structural information on pectins and therefore to be able to better predict their physical and biochemical functionalities.

Recent advances in utilization of pectins in biomedical applications: a review focusing on molecular structure-directing health-promoting properties

The numerous health benefits of pectins justify their inclusion in human diets and biomedical products. This review provides an overview of pectin extraction and modification methods, their physico-chemical characteristics, health-promoting properties, and pharmaceutical/biomedical applications. Pectins, as readily available and versatile biomolecules, can be tailored to possess specific functionalities for food, pharmaceutical and biomedical applications, through judicious selection of appropriate extraction and modification technologies/processes based on green chemistry principles. Pectin's structural and physicochemical characteristics dictate their effects on digestion and bioavailability of nutrients, as well as health-promoting properties including anticancer, immunomodulatory, anti-inflammatory, intestinal microflora-regulating, immune barrier-strengthening, hypercholesterolemia-/arteriosclerosis-preventing, anti-diabetic, anti-obesity, antitussive, analgesic, anticoagulant, and wound healing effects. HG, RG-I, RG-II, molecular weight, side chain pattern, and degrees of methylation, acetylation, amidation and branching are critical structural elements responsible for optimizing these health benefits. The physicochemical characteristics, health functionalities, biocompatibility and biodegradability of pectins enable the construction of pectin-based composites with distinct properties for targeted applications in bioactive/drug delivery, edible films/coatings, nano-/micro-encapsulation, wound dressings and biological tissue engineering. Achieving beneficial synergies among the green extraction and modification processes during pectin production, and between pectin and other composite components in biomedical products, should be key foci for future research.

Pectins that Structurally Differ in the Distribution of Methyl-Esters Attenuate Citrobacter rodentium-Induced Colitis

INTRODUCTION

Pectins have anti-inflammatory properties on intestinal immunity through direct interactions on Toll-like receptors (TLRs) in the small intestine or via stimulating microbiota-dependent effects in the large intestine. Both the degree of methyl-esterification (DM) and the distribution of methyl-esters (degree of blockiness; DB) of pectins contribute to this influence on immunity, but whether and how the DB impacts immunity through microbiota-dependent effects in the large intestine is unknown. Therefore, this study tests pectins that structurally differ in DB in a mouse model with Citrobacter rodentium induced colitis and studies the impact on the intestinal microbiota composition and associated attenuation of inflammation.

METHODS AND RESULTS

Both low and high DB pectins induce a more rich and diverse microbiota composition. These pectins also lower the bacterial load of C. rodentium in cecal digesta. Through these effects, both low and high DB pectins attenuate C. rodentium induced colitis resulting in reduced intestinal damage, reduced numbers of Th1-cells, which are increased in case of C. rodentium induced colitis, and reduced levels of GATA3+ Tregs, which are related to tissue inflammation.

CONCLUSION

Pectins prevent C. rodentium induced colonic inflammation by lowering the C. rodentium load in the caecum independently of the DB.

The Dietary Fiber Pectin: Health Benefits and Potential for the Treatment of Allergies by Modulation of Gut Microbiota

Purpose of Review

The incidence of allergies is increasing and has been associated with several environmental factors including westernized diets. Changes in environment and nutrition can result in dysbiosis of the skin, gut, and lung microbiota altering the production of microbial metabolites, which may in turn generate epigenetic modifications. The present review addresses studies on pectin-mediated effects on allergies, including the immune modulating mechanisms by bacterial metabolites.

Recent Findings

Recently, microbiota have gained attention as target for allergy intervention, especially with prebiotics, that are able to stimulate the growth and activity of certain microorganisms. Dietary fibers, which cannot be digested in the gastrointestinal tract, can alter the gut microbiota and lead to increased local and systemic concentrations of gut microbiota-derived short chain fatty acids (SCFAs). These can promote the generation of peripheral regulatory T cells (T_reg) by epigenetic modulation and suppress the inflammatory function of dendritic cells (DCs) by transcriptional modulation.

The dietary fiber pectin (a plant-derived polysaccharide commonly used as gelling agent and dietary supplement) can alter the ratio of Firmicutes to Bacteroidetes in gut and lung microbiota, increasing the concentrations of SCFAs in feces and sera, and reducing the development of airway inflammation by suppressing DC function.

Summary

Pectin has shown immunomodulatory effects on allergies, although the underlying mechanisms still need to be elucidated. It has been suggested that the different types of pectin may exert direct and/or indirect immunomodulatory effects through different mechanisms. However, little is known about the relation of certain pectin structures to allergies.

Lean and obese microbiota: differences in in vitro fermentation of food-by-products

The aim of the study was to investigate the potential prebiotic effects of food-by-products (cassava bagasse (n=3), orange bagasse (n=2) and passion fruit peel (n=3)) using an in vitro model simulating the proximal colon, and to assess possible differences in fermentation when using faecal microbiota from lean or obese people. Fermentation of the by-products was compared to a control medium and the prebiotic inulin. The effects of the by-products on the dynamics of the gut microbiota differed according to the type of microbiota, as well as the type of by-product used. Principal Coordinate Analysis of the microbiota showed evidence of a clear separate clustering of lean and obese microbiota before the addition of substrates, which disappeared after fermentation, and instead, distinct clusters due to primary carbohydrate composition of the by-products (starch, fructan and pectin) were present. This is evidence that the substrates drove the obese microbiota to a healthier profile, more similar to that of the lean microbiota. Cassava bagasses enriched the beneficial genus Bifidobacterium in the obese microbiota. The production of total SCFA by cassava bagasses by the obese microbiota was higher than for control medium and inulin. Orange bagasses stimulated the growth of the butyrate-producing genus Coprococcus. Passion fruit peels were poorly fermented and generated negligible amounts of intermediate metabolites, indicating slow fermentation. Nevertheless, passion fruit peel fermentation resulted in a microbiota with the highest diversity and evenness, a positive trait regarding host health. In conclusion, the use of food-by-products could be an important step to tackle obesity and decrease the waste of valuable food material and consequently environmental pollution. They are an inexpensive and non-invasive way to be used as a dietary intervention to improve health, as they were shown here to drive the composition of the obese microbiota to a healthier profile.

Challenges of pectic polysaccharides as a prebiotic from the perspective of fermentation characteristics and anti-colitis activity

Several studies are described that contribute to the systematic exploration of new aspects of digestion, fermentation, and biological activities of pectic polysaccharides (PPS) leading to a better understanding of prebiotics. Inflammatory bowel disease (IBD) is thought to be associated with the dysbacteriosis induced by different environmental agents in genetically susceptible persons. PPS are considered as an indispensable gut-microbiota-accessible carbohydrate that play a dominant role in maintaining gut microbiota balance and show a better effect in ameliorating IBD than some traditional prebiotics. The aim of this review is to summarize the fermentation characteristics of PPS, highlight its role in improving IBD, and propose a view that PPS may be a new and effective prebiotic.

Dietary Fiber Modulates the Fermentation Patterns of Cyanidin-3-O-Glucoside in a Fiber-Type Dependent Manner

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

Phocaeicola faecalis sp. nov., a strictly anaerobic bacterial strain adapted to the human gut ecosystem

A novel strictly anaerobic, Gram-negative bacterium, designated as strain FXJYN30E22^T, was isolated from the feces of a healthy woman in Yining county, Xinjiang province, China. This strain was non-spore-forming, bile-resistant, non-motile and rod-shaped. It was found to belong to a single separate group in the Phocaeicola genus based on its 16 S ribosomal RNA (rRNA) gene sequence. Alignments of 16 S rRNA gene sequences showed only a low sequence identity (≤  95.5 %) between strain FXJYN30E22^T and all other Phocaeicola strains in public data bases. The genome (43.0% GC) of strain FXJYN30E22^T was sequenced, and used for phylogenetic analysis which showed that strain FXJYN30E22^T was most closely related to the type strain Phocaeicola massiliensis JCM 13223^T. The average nucleotide identity (ANI) value and digital DNA-DNA hybridization (dDDH) between FXJYN30E22^T and P. massiliensis JCM 13223^T were 90.4 and 41.9 %, which were lower than the generally accepted species boundaries (94.0 and 70 %, respectively). The major cellular fatty acids and polar lipids were anteiso-branched C_15:0 and phosphatidylethanolamine, respectively. The result of genome annotation and KEGG analysis showed that strain FXJYN30E22^T contains a number of genes in polysaccharide and fatty acid synthesis that indicated adaptation to the human gut system. Furthermore, a pbpE (penicillin-binding protein) gene was found in the genome of strain FXJYN30E22^T but in no other Phocaeicola species, which suggested this gene might be contribute to the adaptive capacity of strain FXJYN30E22^T. Based on our data, strain FXJYN30E22^T (= CGMCC1.17870^T/KCTC25195^T) was classified as a novel Phocaeicola species, and the name Phocaeicola faecalis sp. nov., was proposed.

Pectin and homogalacturonan with small molecular mass modulate microbial community and generate high SCFAs via in vitro gut fermentation

The intestinal fermentability of pectic polysaccharides is largely determined by its molecular size. In this study, fermentation properties of enzymatic-modified apple pectin (AP) and homogalacturonans (HG) with high, medium and low molecular weight (Mw) were evaluated by in vitro fermentation model, and their structural changes were also investigated. Results showed that Mw, monosaccharide contents and molecular linearity of the AP hydrolysates were reduced after microbial degradation. On the other hand, culture media supplemented with low-Mw AP (60,300 g/mol) and low-Mw HG (861 g/mol) exhibited lower pH (5.1 and 5.7, respectively) and produced higher total short-chain fatty acid contents (SCFA, 230.40 mmol/L and 187.19 mmol/L, respectively). However, reduced trends in abundance of the pectinolytic microorganisms Faecalibacterium and Eubacterium were showed as Mw of the HG decreased, whereas growth of the SCFA-producer genera Bifidobaacterium, Megasphaera and Allisonella were improved. This work confirmed that low-Mw pectin and homogalacturonan generated more beneficial metabolites, developing structure-microbiota-gut health relationship.

Different co-occurring bacteria enhance or decrease the growth of the microalga Nannochloropsis sp. CCAP211/78

Marine photosynthetic microalgae are ubiquitously associated with bacteria in nature. However, the influence of these bacteria on algal cultures in bioreactors is still largely unknown. In this study, eighteen different bacterial strains were isolated from cultures of Nannochloropsis sp. CCAP211/78 in two outdoor pilot-scale tubular photobioreactors. The majority of isolates was affiliated with the classes Alphaproteobacteria and Flavobacteriia. To assess the impact of the eighteen strains on the growth of Nannochloropsis sp. CCAP211/78, 24-well plates coupled with custom-made LED boxes were used to simultaneously compare replicate axenic microalgal cultures with addition of individual bacterial isolates. Co-culturing of Nannochloropsis sp. CCAP211/78 with these strains demonstrated distinct responses, which shows that the technique we developed is an efficient method for screening the influence of harmful/beneficial bacteria. Two of the tested strains, namely a strain of Maritalea porphyrae (DMSP31) and a Labrenzia aggregata strain (YP26), significantly enhanced microalgal growth with a 14% and 12% increase of the chlorophyll concentration, respectively, whereas flavobacterial strain YP206 greatly inhibited the growth of the microalga with 28% reduction of the chlorophyll concentration. Our study suggests that algal production systems represent a 'natural' source to isolate and study microorganisms that can either benefit or harm algal cultures.

Microwave treatment enhances human gut microbiota fermentability of isolated insoluble dietary fibers

Most insoluble dietary fibers are known to be relatively poorly fermented by the human gut microbiota. Here, the potential of microwave (MW) treatment to enhance the susceptibility of insoluble fruit polysaccharides to fermentation by the human gut microbiota was evaluated. Insoluble fruits dietary fibers before (xylan A, xylan T, and arabinan) and after MW (xylan A-MW, xylan T-MW, and arabinan-MW) treatment were fermented using an in vitro fermentation model. Gas production, shifts in pH, and short chain fatty acids (SCFAs) production showed an increase in fermentability of all tested dietary fibers, with an average 4-fold increase in SCFAs production after microwaving with total SCFAs ranging from 17.1 mM in the arabinan-MW to 40.4 mM in the xylan T-MW. While arabinan-MW and xylan T-MW promoted all three SCFAs proportionally (acetate:propionate:butyrate), xylan A-MW led to a marked and slow increase in butyrate reaching 28.1% of total SCFAs at 24 h. Rearrangements in three-dimensional structure that potentially facilitate bacterial accessibility to the dietary fiber were observed by scanning electron microscopy in xylan A-MW, forming coin-like particles with ~1.1 µm diameter. 16S rRNA gene sequencing indicated that microbiota shifts were related to both treatment (native versus MW) and dietary fiber type with many butyrogenic species being promoted by xylan A-MW. Overall, MW treatment enhanced insoluble dietary fiber fermentability promoting increased SCFAs production and bacterial shifts which are related to health benefits.

Effects of long-term consumption of polysaccharides from the fruit of Lycium barbarum on host's health

Polysaccharides from the fruit of Lycium barbarum (LBPs) are functional molecules with diverse biological functions in vivo and in vitro. This study investigated the long-term consumption of LBPs on host's health in BALB/c mice. Six-week-old male mice (n = 10 each group) were fed either a normal control (NC) diet or supplemented with 200 mg/kg (body weight)/d of LBPs for 14 weeks. Compared with the NC diet, the LBPs diet enhanced the expression of mucin 2 and Claudin5, improved the intestinal barrier morphologically, moreover, promoted the growth of Lactobacillus and strongly increased the production of short-chain fatty acids and IgA (p < 0.05). Feeding LBPs increased the levels of superoxide dismutase and reduced glutathione in the serum, liver and spleen while decreased the levels of alanine aminotransferase and lysozyme in serum and spleen. Besides, the LBPs diet increased the expression of cytokines including tumor necrosis factor α and interleukin-6 and related mRNA but decreased the level of lysozyme. To sum up, chronic intake of LBPs in BALB/c mice improved the oxidation resistance, changed the immune status especially promoted the intestinal immunity. These results may have important implications for LBPs as functional food supplement and for realizing the potential value of LBPs for host's health.

Not All Fibers Are Born Equal; Variable Response to Dietary Fiber Subtypes in IBD

Diet provides a safe and attractive alternative to available treatment options in a variety of diseases; however, research has only just begun to elucidate the role of diet in chronic diseases, such as the inflammatory bowel diseases (IBD). The chronic and highly debilitating IBDs, Crohn disease and ulcerative colitis, are hallmarked by intestinal inflammation, immune dysregulation, and dysbiosis; and evidence supports a role for genetics, microbiota, and the environment, including diet, in disease pathogenesis. This is true especially in children with IBD, where diet-based treatments have shown excellent results. One interesting group of dietary factors that readily links microbiota to gut health is dietary fibers. Fibers are not digested by human cells, but rather fermented by the gut microbes within the bowel. Evidence has been mounting over the last decade in support of the importance of dietary fibers in the maintenance of gut health and in IBD; however, more recent studies highlight the complexity of this interaction and importance of understanding the role of each individual dietary fiber subtype, especially during disease. There are roughly ten subtypes of dietary fibers described to date, categorized as soluble or insoluble, with varying chemical structures, and large differences in their fermentation profiles. Many studies to date have described the benefits of the byproducts of fermentation in healthy individuals and the potential health benefits in select disease models. However, there remains a void in our understanding of how each of these individual fibers affect human health in dysbiotic settings where appropriate fermentation may not be achieved. This review highlights the possibilities for better defining the role of individual dietary fibers for use in regulating inflammation in IBD.

Pectin limits epithelial barrier disruption by Citrobacter rodentium through anti-microbial effects

SCOPE

C. rodentium is the murine equivalent of Enteropathogenic Escherichia. coli (EPEC) and Enterohemorrhagic Escherichia coli (EHEC) which induce damage to the intestinal epithelial barrier that results in diarrhea and intestinal inflammation. Dietary fibre intake can be an effective approach to limit epithelial damage by these enteric pathogens. Therefore, the protective effect of dietary fibre pectin against dysfunction of epithelial barrier integrity upon C. rodentium infection was investigated.

METHODS AND RESULTS

Pectins that structurally differed in the degree and distribution of methylesters were tested on barrier protective effects on epithelial cells against C. rodentium by measuring transepithelial electrical resistance and lucifer yellow fluxes. All three pectins protected the epithelial barrier from C. rodentium induced damage in a structure-independent manner. These barrier protective effects were also independent of pectin-induced TLR2 activation. Furthermore, the pectins induced anti-adhesive effects on C. rodentium by interacting with C. rodentium and not with epithelial cells. This may be explained by antimicrobial effects of pectins on C. rodentium and not on other enteric bacteria including Lactobacillus plantarum and E. coli. A competition ELISA for binding of C. rodentium to pectin supported this finding as it showed that pectin interacts strongly with C. rodentium, whereas it interacts weakly or not with L. plantarum or E. coli.

CONCLUSION

These findings demonstrate that pectin protects the epithelial barrier from C. rodentium induced damage by inducing anti-microbial effects.

Opportunities of prebiotics for the intestinal health of monogastric animals

The goal of prebiotic applications from different sources is to improve the gut ecosystem where the host and microbiota can benefit from prebiotics. It has already been recognized that prebiotics have potential roles in the gut ecosystem because gut microbiota ferment complex dietary macronutrients and carry out a broad range of functions in the host body, such as the production of nutrients and vitamins, protection against pathogens, and maintenance of immune system balance. The gut ecosystem is very crucial and can be affected by numerous factors consisting of dietary constituents and commensal bacteria. This review focuses on recent scientific evidence, confirming a beneficial effect of prebiotics on animal health, particularly in terms of protection against pathogenic bacteria and increasing the number of beneficial bacteria that may improve epithelial cell barrier functions. It has also been reviewed that modification of the gut ecosystem through the utilization of prebiotics significantly affects the intestinal health of animals. However, the identification and characterization of novel potential prebiotics remain a topical issue and elucidation of the metagenomics relationship between gut microbiota alteration and prebiotic substances is necessary for future prebiotic studies.