SCFA Production Research Articles

Gas-Mediated Intestinal Microbiome Regulation Prompts the Methanol Extract of Schizonepetae Spica to Relieve Colitis.

Intestinal dysbiosis plays an important role in the pathogenesis of colitis (UC). Schizonepetae Herba can achieve anti-inflammatory effects as a medicine and food homologous vegetable. Luteolin, eriodictyol, fisetin, and kaempferol are the main anti-inflammatory active compounds obtained through mass spectrometry from the methanol extract of Schizonepetae Spica (JJSM). JJSM intervention resulted in attenuated weight loss, high disease-activity-index score, colon length shortening and colonic pathological damage in DSS-induced colitis mice. Interestingly, hydrogen sulfide (H2S) was inhibited remarkably, which is helpful to elucidate the relationship between active substance and intestinal flora. Furthermore, JJSM administration improved intestinal flora with down-regulating the abundance of harmful bacteria such as Clostridiales and Desulfovibrio and up-regulating the abundance of beneficial bacteria such as Muribaculaceae and Ligolactobacillus and enhanced the production of SCFAs. It is worth noticing that Desulfovibrio is related to the production of intestinal gas H2S. The elevated levels of Desulfovibrio and H2S will hasten the onset of colitis, which is a crucial risk factor for colitis. The results displayed that JJSM could considerably ameliorate colitis by rebuilding H2S-related intestinal flora, which provides a new therapeutic strategy for Schizonepetae Spica to be utilized as a functional food and considered as an emerging candidate for intestinal inflammation.

Influence of structural features and feruloylation on fermentability and ability to modulate gut microbiota of arabinoxylan in in vitro fermentation.

Arabinoxylan (AX) is a versatile polysaccharide that shows various effects in modulating gut microbiota and health. The influence of arabinoxylan carbohydrate structural feature and feruloylation on fermentability and the effect of modulation of gut microbiota of AX was not clear. Arabinoxylans from rice bran and corn bran (RAX and CAX), and their deferulyolated counterpart dRAX and dCAX were fermented using an in vitro fermentation model. Structural information was determined based on monosaccharide composition. Gas production of fermentation products, SCFAs production, pH change, and microbiota change were measured. RAX and dRAX posessed lower A/X ratio compared with CAX and dCAX. The gas and total SCFAs production were lower in RAX and dRAX, and the butyrate production were higher in RAX and dRAX compared with CAX and dCAX. Butyrate production was lower at dRAX compared to RAX. On the other hand, butyrate production was higher in dCAX than in CAX. The microbiota shift were different for the four fibers. The AXs from rice have a higher A/X ratio than the AXs from maize, suggesting more branching and a more complex side chain. The structural difference was crucial for the difference in fermentation pattern. Different Bacteroides species are responsible for the utilization of rice AXs and corn AXs. Although feruloylation had a minor effect on the overall fermentation pattern, it significantly affected butyrate production and alpha diversity. dRAX promoted less butyrate than RAX, which is associated with a significantly lower amount of Faecalibacterium prausnitzi. dCAX promoted more butyrate than CAX, which may be associated with a lower amount of Bacteroides ovatus and a higher amount of Blautia in dCAX compared to CAX. The effects of feruloylation on the fermentation pattern and the resulted microbiota shift of AX varied depending on the carbohydrate structure.

Breast cancer patients from the Midwest region of the United States have reduced levels of short-chain fatty acid-producing gut bacteria

As geographical location can impact the gut microbiome, it is important to study region-specific microbiome signatures of various diseases. Therefore, we profiled the gut microbiome of breast cancer (BC) patients of the Midwestern region of the United States. The bacterial component of the gut microbiome was profiled utilizing 16S ribosomal RNA sequencing. Additionally, a gene pathway analysis was performed to assess the functional capabilities of the bacterial microbiome. Alpha diversity was not significantly different between BC and healthy controls (HC), however beta diversity revealed distinct clustering between the two groups at the species and genera level. Wilcoxon Rank Sum test revealed modulation of several gut bacteria in BC specifically reduced abundance of those linked with beneficial effects such as Faecalibacterium prausnitzii. Machine learning analysis confirmed the significance of several of the modulated bacteria found by the univariate analysis. The functional analysis showed a decreased abundance of SCFA (propionate) production in BC compared to HC. In conclusion, we observed gut dysbiosis in BC with the depletion of SCFA-producing gut bacteria suggesting their role in the pathobiology of breast cancer. Mechanistic understanding of gut bacterial dysbiosis in breast cancer could lead to refined prevention and treatment.

The maca protein ameliorates DSS-induced colitis in mice by modulating the gut microbiota and production of SCFAs.

Maca is a functional food with anti-inflammatory activity, and it is rich in protein. Currently, inflammatory bowel disease (IBD) is a common gastrointestinal disease. However, there is little research focusing on the effect of maca protein (MCP) on IBD. In this study, we extracted MCP from maca root and explored its effect and mechanism on improving dextran sodium sulfate (DSS)-induced IBD in mice. The results indicated that MCP intervention alleviated the clinical symptoms and colon tissue damage of mice with DSS-induced colitis and inhibited the expression of inflammatory factors. Moreover, it can modulate the gut microbiota composition in mice with DSS-induced colitis. The regulation is achieved by reducing the relative abundance of the IBD-exacerbating key bacterial genera: Lachnospiraceae_NK4A136_group, Bacteroides, Desulfovibrio, Prevotella, Helicobacter and Sutterella, while increasing the relative abundance of the IBD-alleviating key bacterial genera: norank_f_Muribaculaceae, Lactobacillus, Oscillospira, Akkermansia and Bifidobacterium. MCP can also promote the production of short-chain fatty acids (SCFAs). The further western blotting results indicated that MCP can regulate the Treg/Th17 immune balance in mice with colitis via the SCFAs-GPR41/43/HDAC1 signaling pathway. Overall, MCP can alleviate colitis by comprehensively regulating the gut microbiota and inflammatory response. It may be a promising functional component that reduces the risk of colitis by maintaining intestinal health.

Performance Indicators, Coccidia Oocyst Counts, Plasma Biochemical Parameters and Fermentation Processes in the Cecum of Rabbits Fed a Diet with the Addition of Black Cumin Seed Meal

Abstract The aim of this study was to determine the effects of dietary supplementation with black cumin seed meal on growth performance parameters, coccidia oocyst counts, plasma biochemical parameters and cecal fermentation processes in growing rabbits. A total of 40 male Californian rabbits at 35 days of age were divided into two feeding groups: Control (complete rabbit diet) and Black cumin (2% of the complete diet was replaced with black cumin seed meal). Dietary supplementation with black cumin did not affect growth performance parameters, but it reduced coccidia oocyst counts in the feces of 63-day-old rabbits. Increased liver weight and elevated plasma albumin levels were noted in these rabbits. A significant decrease in small intestinal digesta viscosity was also observed in rabbits fed a diet supplemented with black cumin seed meal. The above change suppressed the formation of putrefactive compounds, i.e. ammonia and branched short-chain fatty acids (SCFA s) in the cecum, but it did not decrease the production of major SCFA s, i.e. acetic, propionic and butyric acids. The current study demonstrated that the dietary addition of 2% black cumin seed meal exerted a modulatory effect on gastrointestinal function, but it did not compromise microbial enzyme activity or SCFA production in the cecum.

A pilot study of dietary fibres on pathogen growth in an ex vivo colonic model reveals their potential ability to limit vancomycin-resistant Enterococcus expansion.

Aim: Dietary fibre is important for shaping gut microbiota. The aim of this pilot study was to investigate the impact of dietary fibres on pathogen performance in the presence of gut microbiota. Methods: In an ex vivo gut model, pooled faecal samples were spiked with a cocktail of representative gastrointestinal pathogens and fermented with yeast β-glucan for 24 hours, after which 16S rRNA amplicon sequencing and short-chain and branched-chain fatty acid (SCFA and BCFA) analyses were performed. In addition, oat β-glucan, arabinoxylan, yeast β-glucan, and galactooligosaccharides were each tested against individual representative pathogens and pathogen growth was assessed via qPCR. Glucose served as a control carbon source. Results: Based on 16S rRNA amplicon sequencing, yeast β-glucan selected for higher proportions of Bacteroides (P = 0.0005, ~6 fold) and Clostridia (P = 0.005, ~3.6 fold) while species of Escherichia/Shigella (P = 0.021, ~2.8 fold) and Lactobacillus (P = 0.007, ~ 15.7-fold) were higher in glucose. Pathogen relative abundance did not differ between glucose and yeast β-glucan. In the absence of pathogens, higher production of BCFAs (P = 0.002) and SCFAs (P = 0.002) fatty acids was observed for fibre group(s). For individual pathogens, yeast β-glucan increased growth of Escherichia coli, Salmonella typhimurium, and Listeria monocytogenes (P < 0.05), arabinoxylan increased S. typhimurium (P < 0.05). Tested fibres decreased vancomycin-resistant Enterococcus faecium (P < 0.05), with yeast β-glucan causing a 1-log reduction (P < 0.01), while galactooligosaccharides decreased L. monocytogenes (P < 0.05). Conclusion: Tested fibres differentially influenced the growth of pathogens, but yeast β-glucan could represent a dietary strategy to help limit vancomycin-resistant enterococci (VRE) expansion in the gut.

Lactate and buyrate proportions, methanogen growth and gas production during in vitro dietary fibre fermentation all depend on fibre concentration

Dietary fibre (DF) concentration plays a critical role in the gas kinetics and short-chain fatty acid production profiles during in vitro human faecal fermentation. However, the mechanisms leading to concentration-dependent fermentation outcomes are unknown. In this study, fructo-oligosaccharides and pectin at three concentrations (0.2, 0.4 and 0.6g/44mL), were selected to investigate the effect of DF type and concentration on human gut microbiota. An absolute quantification method was applied to determine the microbial biomass and load for each genus. Additionally, the gas kinetics and fermentation metabolites (acetate, propionate, butyrate, i-butyrate, valerate, i-valerate, formate, succinate, methanol, ethanol and lactate) were measured. Results showed that DF type and concentration affected the microbial diversity, microbial loads and metabolite profiles to different extents. At high DF concentrations Methanobrevibacter , a genus of Archaea, was found to increase by ∼28 fold for FOS, and ∼93 fold for pectin. We propose three main pathways, dictated by DF type and concentration, driving the observed alterations in microbial loads and metabolite profiles. Firstly, the lactate cross-feeding pathway could lead to increased butyrate production. Secondly, methanogenesis from H 2 and CO 2 , and thirdly, reductive acetyl-CoA pathways resulted in the conversion of gases to increase microbial biomass. Understanding these underlying mechanisms allows for tailoring DF fermentation by varying their concentrations to control SCFA and gas production. • Higher DF concentration led to increased butyrate proportion via lactate cross-feeding. • Higher DF concentration led to more gas production, triggering gas cross-feeding. • Absolute quantification of microbiota revealed concentration-dependent biomass shifts. • Methanogenesis and reductive acetyl-CoA pathways led to biomass growth. • Cross-feeding of lactate and gases also depended on DF type.

Role of extracted phytochemicals from Rosa sterilis S. D. Shi in DSS-induced colitis mice: potential amelioration of UC.

Rosa sterilis S. D. Shi is a new variety of R. roxburghii Tratt and its fruits are rich in bioactive components, but its effects and mechanisms against intestinal inflammation are currently unknown. In this study, the main components of the ethanol extract of R. sterilis S. D. Shi fruits (RSE) were identified and its anti-inflammatory efficacy in DSS-induced mice was evaluated. A total of nine compounds were identified, including 1-O-E-cinnamoyl-(6-arabinosylglucose), ellagic acid-O-rhamnoside, (epi) catechin, niga-ichigoside F1, etc. The results demonstrated that RSE ameliorated DSS-induced inflammation in mouse colon tissues by increasing mucin expression, reducing the production of TNF-α, IL-1β, and IL-6, inhibiting the mRNA expression of COX-2 and iNOS, regulating the composition of gut microbiota through suppressing Escherichia-Shigella while increasing Akkermansia muciniphila, and promoting the production of SCFAs, especially acetic acid. Briefly, RSE showed outstanding potential for anti-inflammatory activity and is expected to be a promising dietary supplement for healthy individuals to prevent or relieve colitis and colitis-related diseases, which provided a new direction for functional food development.

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.

Modulation effect of black rice dietary fiber on the metabolism and fermentation of cyanidin-3-glucoside in an in vitro human colonic model.

Black rice (Oryza sativa L.) is a great source of anthocyanins and dietary fiber and possesses various health-promoting properties. The modulating effect of insoluble dietary fiber (IDF) from black rice on the fermentation of cyanidin-3-O-glucoside (Cy3G) in an in vitro human colonic model, together with the possible microbiota-mediated mechanisms, was investigated. The combined Cy3G and IDF fermentation can promote the biotransformation of Cy3G into phenolic compounds such as cyanidin and protocatechuic acid with stronger antioxidant activities and increase the total production of SCFAs during the fermentation of Cy3G. 16S rRNA sequencing analysis revealed that the addition of IDF modulated the microbiota structure and bloomed Bacteroidota and Prevotellaceae-related genera, which were positively correlated with metabolites of Cy3G, thus potentially regulating the microbial metabolism of Cy3G. The work is of great significance for elucidating the material basis of the health benefits of black rice.

The role of IL-10 in regulating inflammation and gut microbiome in mice consuming milk kefir and orally challenged with S. Typhimurium.

Kefir has been suggested as a possible bacterial prophylaxis against Salmonella and IL-10 production seems to be crucial in the pathogenesis of salmonellosis in mice. This study evaluated the role of IL-10 in the inflammation and gut microbiome in mice consuming milk kefir and orally challenged with Salmonella enterica serovar Typhimurium. C57BL wild type (WT) (n = 40) and C57BL IL-10-/- (KO) (n = 40) mice were subdivided into eight experimental groups either treated or not with kefir. In the first 15 days, the water groups received filtered water (0.1 mL) while the kefir groups received milk kefir (10% w/v) orally by gavage. Then, two groups of each strain received a single dose (0.1 mL) of the inoculum of S. Typhimurium (ATCC 14028, dose: 106 CFU mL-1). After four weeks, the animals were euthanized to remove the colon for further analysis. Kefir prevented systemic infections only in IL-10-/- mice, which were able to survive, regulate cytokines, and control colon inflammation. The abundance in Lachnospiraceae and Roseburia, and also the higher SCFA production in the pre-infection, showed that kefir has a role in intestinal health and protection, colonizing and offering competition for nutrients with the pathogen as well as acting in the regulation of salmonella infectivity only in the absence of IL-10. These results demonstrate the role of IL-10 in the prognosis of salmonellosis and how milk kefir can be used in acute infections.

Early intestinal microbiota changes in aged and adult mice with sepsis.

The mortality rate associated with sepsis in elderly individuals is higher than that in younger individuals. The intestinal microbiota has been demonstrated to play an important role in the occurrence and development of sepsis. The purpose of this study was to investigate the differences in the intestinal microbiota between aged and adult mice with sepsis. Thirty male C57BL mice were randomly divided into two groups: 15 in the adult group (AD group) and 15 in the age group (Age group). All the mice underwent caecal ligation and puncture to induce sepsis. Mice faeces were collected, and analysed using 16S rRNA sequencing. The liver and colon tissues were collected. There were significant differences in intestinal microbiota composition between the two groups. Compared with adult sepsis mice, the diversity of intestinal microbiota in the aged group was significantly reduced and the structure of dominant intestinal microbiota was changed. In the Age group, the microbiota associated with inflammatory factors increased, and the microbiota associated with the production of SCFAs (Ruminiclostridium, Prevotellaceae_UCG-001, Rikenella, Parabacteroides, Oscillibacter, Odoribacter, Muribaculum, Lachnoclostridium, Intestinimonas, Faecalibaculum, Anaerotruncus, Alloprevotella and Absiella) decreased. The metabolic pathways related to the microbiota also changed. Moreover, the proportion of inflammatory factors in Age group was higher than that in AD group. Our results showed that there were significant differences in the abundance and structure of microbiota between aged and adult sepsis mice, Aged sepsis mice have more severe intestinal microbiota destruction and liver tissue inflammation than adult sepsis mice.

Integrative metagenomic and metabolomic analyses reveal gut microbiota-derived multiple hits connected to development of gestational diabetes mellitus in humans

ABSTRACT Gestational diabetes mellitus (GDM) is characterized by the development of hyperglycemia and insulin resistance during the second or third trimester of pregnancy, associated with considerable risks to both the mother and developing fetus. Although emerging evidence suggests an association between the altered gut microbiota and GDM, remarkably little is known about the microbial and metabolic mechanisms that link the dysbiosis of the gut microbiota to the development of GDM. In this study, a metagenome-wide association study and serum metabolomics profiling were performed in a cohort of pregnant women with GDM and pregnant women with normal glucose tolerance (NGT). We identified gut microbial alterations associated with GDM and linked to the changes in circulating metabolites. Blood metabolite profiles revealed that GDM patients exhibited a marked increase in 2-hydroxybutyric acid and L-alpha-aminobutyric acid, but a decrease in methionine sulfoxide, allantoin, and dopamine and dopaminergic synapse, when compared with those in NGT controls. Short-chain fatty acid-producing genera, including Faecalibacterium, Prevotella, and Streptococcus, and species Bacteroides coprophilus, Eubacterium siraeum, Faecalibacterium prausnitzii, Prevotella copri, and Prevotella stercorea, were significantly reduced in GDM patients relative to those in NGT controls. Bacterial co-occurrence network analysis revealed that pro-inflammatory bacteria were over-represented as the core species in GDM patients. These microbial and metabolic signatures are closely associated with clinical parameters of glucose metabolism in GDM patients and NGT controls. In conclusion, we identified circulating dopamine insufficiency, imbalanced production of SCFAs, and excessive metabolic inflammation as gut microbiota-driven multiple parallel hits linked to GDM development. This work might explain in part the mechanistic link between altered gut microbiota and GDM pathogenesis, and suggest that gut microbiota may serve as a promising target to intervene in GDM.

The administration of Enterococcus faecium SF68 counteracts compositional shifts in the gut microbiota of diet-induced obese mice.

Microorganisms with probiotic properties are eliciting an increasing interest as coadjuvants in the prevention and treatment of obesity through modulation of the gut microbiota. In this study, a probiotic formulation based on Enterococcus faecium SF68 was administered to mice fed with a high-fat diet (HFD) to evaluate its efficacy in reducing body mass gain and in modulating the intestinal bacterial composition. Both stool and ileum samples were collected from untreated and treated mice and absolute abundances of specific taxa constituting the gut microbial consortium were evaluated. SF68 administration significantly reduced the HFD-induced weight gain. In these animals, the microbial gut composition shifted toward an enrichment in microbes positively correlated with mucus thickness, lower inflammation, lower glycemia levels, and SCFA production (i.e., Bifidobacterium, Akkermansia, and Faecalibacterium), as well as a depletion in bacterial phyla having a key role in obesity (i.e., Firmicutes, Proteobacteria). Our results demonstrate the efficacy of E. faecium SF68 in adjusting the composition of the dysbiotic microbiota of HFD-fed animals, thus ameliorating clinical conditions and exerting anti-obesity effects.

Investigation of the impact of black chokeberry polyphenols in different matrices on the human gut microbiota using the in vitro model of the large intestine (TIM-2)

BACKGROUND: Despite the great range of health-beneficial activities associated with dietary polyphenols, their influence on gut ecology remains poorly understood. Only a few studies have examined the impact of black chokeberry polyphenols present in different matrices on human gut microbiota, and in fact none have examined encapsulated black chokeberry polyphenols. OBJECTIVE: The objective of this study was to evaluate the effect of black chokeberry polyphenols in pulp, extract and encapsulate (in a maltodextrin:gum Arabic polymer system) on human gut microbiota and fecal short-chain and branched-chain fatty acids (SCFA and BCFA, respectively). METHODS: The effect of black chokeberry polyphenols on gut microbiota was tested in a validated, dynamic in vitro model of the colon (TIM-2) for 24 h by applying five different interventions (Pulp, Extract, Encapsulate, Encapsulate control, SIEM) to the standardized microbiota from five healthy donors. RESULTS: We observed that the fermentation of black chokeberry polyphenols in the in vitro colon model resulted in shifts in the standardized microbiota and differentiation in the extent of the production of SCFA and BCFAs. Synergy between maltodextrin+gum Arabic+polyphenols resulted in an increase in the relative abundances of some health-promoting taxa and decrease in the disease related taxa Alistipes. Encapsulation increased the SCFA production and decreased the BCFA production in the lumen. CONCLUSIONS: Although encapsulation of polyphenols may provide a robust way for their protection during their transit along the upper gastrointestinal tract, their effect on the gut microbiota should be further investigated both by using different coating materials and with in vivo studies.

A comparison study on polysaccharides extracted from Rosa sterilis S.D.Shi using different methods: Structural and in vitro fermentation characterizations

In this study, the structural and in vitro fermentation characterizations of Rosa sterilis S.D.Shi polysaccharides (RSP), extracted by hot water (HW), acid (AA), alkali (AK) and enzyme (EM) were investigated for the first time. The results indicated that extraction methods exhibited significant effects on the structure of RSPs, thus resulting in different probiotic effects. HW-RSP and AA-RSP had high contents of Gal, Glc and GalA, while AK-RSP and EM-RSP mainly contained Ara, Gal and GalA. EM-RSP was rich in RG-I and its size of average side chain were the largest. Moreover, HW-RSP and AK-RSP exhibited the smallest (57.55 kDa) and largest (922.20 kDa) molecular weights, respectively. All RSPs promoted the production of total SCFAs and the growth of beneficial bacteria like Bifidobacterium, Bacteroides, Faecalibacterium and Paraclostrium to varying degrees, but inhibited the growth of pathogenic bacteria such as Escherichia-shigella, thereby regulating the composition of gut microbiota. Furthermore, the function prediction results showed that EM-RSP had the most special metabolic pathways. Collectively, our findings provide new insights into the relationship between the structure and probiotic function of RSPs, and offer theoretical basis for the development of functional products of Rosa sterilis S.D.Shi.

Bone loss is ameliorated by fecal microbiota transplantation through SCFA/GPR41/ IGF1 pathway in sickle cell disease mice

Bone loss is common in sickle cell disease (SCD), but the molecular mechanisms is unclear. Serum insulin-like growth factor 1 (IGF1) was low in SCD subjects and SCD mice. To determine if decreased IGF1 associated with low bone mass in SCD is due to reduced SCFA production by gut microbiota, we performed reciprocal fecal microbiota transplantation (FMT) between healthy control (Ctrl) and SCD mice. uCT and histomorphometry analysis of femur showed decreased bone volume/total volume (BV/TV), trabecular number (Tb.N), osteoblast surface/bone surface (Ob.S/BS), mineralizing surface/ bone surface (MS/BS), inter-label thickness (Ir.L.Th) in SCD mice were significantly improved after receiving Ctrl feces. Bone formation genes Alp, Col1, Runx2, and Dmp1 from SCD mice were significantly decreased and were rescued after FMT from Ctrl feces. Transplantation of Ctrl feces increased the butyrate, valerate, and propionate levels in cecal content of SCD mice. Decreased G-coupled protein receptors 41 and 43 (GPR41 and GPR43) mRNA in tibia and lower IGF1 in bone and serum of SCD mice were partially restored after FMT from Ctrl feces. These data indicate that the healthy gut microbiota of Ctrl mice is protective for SCD bone loss through regulating IGF1 in response to impaired bacterial metabolites SCFAs.

The modulation of gut microbiota by herbal medicine to alleviate diabetic kidney disease - A review.

The treatment of diabetic kidney disease (DKD) has been the key concern of the medical community. Herbal medicine has been reported to alleviate intestinal dysbiosis, promote the excretion of toxic metabolites, and reduce the secretion of uremic toxins. However, the current understanding of the modulation of the gut microbiota by herbal medicine to delay the progression of DKD is still insufficient. Consequently, we reviewed the knowledge based on peer-reviewed English-language journals regarding regulating gut microbiota by herbal medicines in DKD. It was found that herbal medicine or their natural extracts may have the following effects: modulating the composition of intestinal flora, particularly Akkermansia, Lactobacillus, and Bacteroidetes, as well as adjusting the F/B ratio; increasing the production of SCFAs and restoring the intestinal barrier; reducing the concentration of uremic toxins (p-cresol sulfate, indole sulfate, TMAO); inhibiting inflammation and oxidative stress.

Characterization of diet-dependent temporal changes in circulating short-chain fatty acid concentrations: A randomized crossover dietary trial

Production of SCFAs from food is a complex and dynamic saccharolytic fermentation process mediated by both human and gut microbial factors. Knowledge of SCFA production and of the relation between SCFA profiles and dietary patterns is lacking. Temporal changes in SCFA concentrations in response to 2 contrasting diets were investigated using a novel GC-MS method. Samples were obtained from a randomized, controlled, crossover trial designed to characterize the metabolic response to 4 diets. Participants (n = 19) undertook these diets during an inpatient stay (of 72 h). Serum samples were collected 2 h after breakfast (AB), after lunch (AL), and after dinner (AD) on day 3, and a fasting sample (FA) was obtained on day 4. The 24-h urine samples were collected on day 3. In this substudy, samples from the 2 extreme diets representing a diet with high adherence to WHO healthy eating recommendations and a typical Western diet were analyzed using a bespoke GC-MS method developed to detect and quantify 10 SCFAs and precursors in serum and urine samples. Considerable interindividual variation in serum SCFA concentrations was observed across all time points, and temporal fluctuations were observed for both diets. Although the sample collection timing exerted a greater magnitude of effect on circulating SCFA concentrations, the unhealthy diet was associated with a lower concentration of acetic acid (FA: coefficient: -17.0; SE: 5.8; P-trend = 0.00615), 2-methylbutyric acid (AL: coefficient: -0.1; SE: 0.028; P-trend = 4.13 × 10-4 and AD: coefficient: -0.1; SE: 0.028; P-trend = 2.28 × 10-3), and 2-hydroxybutyric acid (FA: coefficient: -15.8; SE: 5.11; P-trend: 4.09 × 10-3). In contrast, lactic acid was significantly higher in the unhealthy diet (AL: coefficient: 750.2; SE: 315.2; P-trend = 0.024 and AD: coefficient: 1219.3; SE: 322.6; P-trend: 8.28 × 10-4). The GC-MS method allowed robust mapping of diurnal patterns in SCFA concentrations, which were affected by diet, and highlighted the importance of standardizing the timing of SCFA measurements in dietary studies. This trial was registered on the NIHR UK clinical trial gateway and with ISRCTN as ISRCTN43087333.

In vitro fermentation of pretreated oat bran by human fecal inoculum and impact on microbiota

• There was no significant change in dietary fiber and β-glucan content after in vitro digestion of pretreated oat bran. • The steaming oat bran had a greater effect on inhibiting Escherichia-Shigella and promoting Faecalibacterium prausnitzii . • The steaming oat bran produced more acetic acid, propionic acid, and butyric acid than the microwave and hot-air drying oat bran. • Steaming was the most effective way that could modulate the diversity of the intestinal flora and effectively prohibit the multiplication of harmful bacteria. Owing to its potential role in improving intestinal health, oat bran has received a lot of attention. In vitro digestion and fermentation were performed on oat brans that had been pretreated with steaming, microwave, and hot-air drying. The results showed that the dietary fiber after in vitro digestion and β -glucan content of pretreated oat brans changed insignificantly (p > 0.05). The abundance of Firmicutes and Proteobacteria varied significantly between samples (p < 0.05). The steaming oat bran was utilized by gut microbiota to produce acetate, propionate, and butyrate, the relative abundance of Faecalibacterium prausnitzii significantly increased, and Escherichia-Shigella significantly decreased. Furthermore, the genus level flora differed significantly between steaming, microwave, and hot-air drying oat bran. Overall, steaming improved oat bran fermentability, promoting increased SCFA production and bacterial shifts associated with health benefits. Our findings provide a solid foundation for further research into the role of oat bran and gut microbiota in host health.