Fecal Short-chain Fatty Acids Research Articles

Fecal Short Chain Fatty Acids Predict Eating Behavior of Postmenopausal Women After Completion of a Dietary Pulses Intervention

Fecal Short Chain Fatty Acids Predict Eating Behavior of Postmenopausal Women After Completion of a Dietary Pulses Intervention

Influence of Blackcurrant Anthocyanins on Fecal Short Chain Fatty Acids and Their Associations With Bone Health in Peri- and Early Postmenopausal Women

Influence of Blackcurrant Anthocyanins on Fecal Short Chain Fatty Acids and Their Associations With Bone Health in Peri- and Early Postmenopausal Women

Fecal bacteria and short-chain fatty acids in irritable bowel syndrome: Relations to subtype.

The relationship between gut microbiota and irritable bowel syndrome (IBS) subtype is unclear. We aimed to explore whether differences in fecal bacteria composition and short-chain fatty acid (SCFA) levels were associated with subtypes and symptoms of IBS. All participants delivered fecal samples and self-reports on IBS Symptom Severity Score (IBS-SSS), Bristol Stool Scale (BSS), and Gastrointestinal Symptom Rating Scale (GSRS). Fecal bacteria composition was assessed by the GA-map® Dysbiosis Test based on 16S rRNA sequences of bacterial species/groups. SCFAs were analyzed by vacuum distillation followed by gas chromatography. Sixty patients with IBS were included (mean age 38 years, 46 [77%] females): Twenty-one patients were classified as IBS-D (diarrhea), 31 IBS-M (mixed diarrhea and constipation), and eight IBS-C (constipation). Forty-two healthy controls (HCs) (mean age 35 years, 27 [64%] females) were included. Patients had a significantly higher relative frequency of dysbiosis, lower levels of Actinobacteria, and higher levels of Bacilli than HCs. Eight bacterial markers were significantly different across IBS subgroups and HCs, and 13 bacterial markers were weakly correlated with IBS symptoms. Clostridia and Veillonella spp. had a weak negative correlation with constipation scores (GSRS) and a weak positive correlation with loose stools (BSS). Diarrhea scores (GSRS) and looser stool (BSS) were weakly correlated with levels of total SCFAs, acetic and butyric acid. Levels of total SCFAs and acetic acid were weakly correlated with symptom severity (IBS-SSS). Patients with IBS had a different fecal bacteria composition compared to HCs, and alterations of SCFAs may contribute to the subtype.

Gut microbiome signatures associated with type 2 diabetes in obesity in Mongolia.

Mongolian people possess a unique dietary habit characterized by high consumption of meat and dairy products and fewer vegetables, resulting in the highest obesity rate in East Asia. Although obesity is a known cause of type 2 diabetes (T2D), the T2D rate is moderate in this population; this is known as the "Mongolian paradox." Since the gut microbiota plays a key role in energy and metabolic homeostasis as an interface between food and body, we investigated gut microbial factors involved in the prevention of the co-occurrence of T2D with obesity in Mongolians. We compared the gut microbiome and metabolome of Mongolian adults with obesity with T2D (DO: n = 31) or without T2D (NDO: n = 35). Dysbiotic signatures were found in the gut microbiome of the DO group; lower levels of Faecalibacterium and Anaerostipes which are known as short-chain fatty acid (SCFA) producers and higher levels of Methanobrevibacter, Desulfovibrio, and Solobacterium which are known to be associated with certain diseases. On the other hand, the NDO group exhibited a higher level of fecal SCFA concentration, particularly acetate. This is consistent with the results of the whole shotgun metagenomic analysis, which revealed a higher relative abundance of SCFA biosynthesis-related genes encoded largely by Anaerostipes hadrus in the NDO group. Multiple logistic regression analysis including host demographic parameters indicated that acetate had the highest negative contribution to the onset of T2D. These findings suggest that SCFAs produced by the gut microbial community participate in preventing the development of T2D in obesity in Mongolians.

Gut microbial features and dietary fiber intake predict gut microbiota response to resistant starch supplementation

ABSTRACT Resistant starch (RS) consumption can have beneficial effects on metabolic health, but the response, in terms of effects on the gut microbiota and host physiology, varies between individuals. Factors predicting the response to RS are not yet established and would be useful for developing precision nutrition approaches that maximize the benefits of dietary fiber intake. We sought to identify predictors of gut microbiota response to RS supplementation. We enrolled 76 healthy adults into a 7-week crossover study with 59 individuals completing the study. Participants consumed RS type 2 (RS2), RS type 4 (RS4), and digestible starch, for 10 d each with 5-d washout periods in between. We collected fecal and saliva samples and food records during each treatment period. We performed 16S rRNA gene sequencing and measured fecal short-chain fatty acids (SCFAs), salivary amylase (AMY1) gene copy number, and salivary amylase activity (SAA). Dietary fiber intake was predictive of the relative abundance of several amplicon sequence variants (ASVs) at the end of both RS treatments. AMY1-related metrics were not predictive of response to RS. SAA was only predictive of the relative abundance of one ASV after digestible starch supplementation. Interestingly, SCFA concentrations increased the most during digestible starch supplementation. Treatment order (the order of consumption of RS2 and RS4), alpha diversity, and a subset of ASVs were predictive of SCFA changes after RS supplementation. Based on our findings, dietary fiber intake and gut microbiome composition would be informative if assessed prior to recommending RS supplementation because these data can be used to predict changes in specific ASVs and fecal SCFA concentrations. These findings lay a foundation to support the premise that using a precision nutrition approach to optimize the benefits of dietary fibers such as RS could be an effective strategy to compensate for the low consumption of dietary fiber nationwide.

Improvement of insulin sensitivity by dietary fiber consumption during late pregnant sows is associated with gut microbiota regulation of tryptophan metabolism

BackgroundDietary fiber (DF) consumption was reported to improve insulin sensitivity, change the tryptophan metabolism, and alter the gut microbiota. Herein, this study aimed to investigate the effects of DF consumption on insulin sensitivity, tryptophan metabolism, and gut microbiota composition in sows during late pregnancy, and explore the relationship between tryptophan metabolites and insulin sensitivity regulated by DF supplementation.ResultsTwelve sows were randomly assigned to two dietary treatment groups (six/group): the low-fiber (LF) group, which was fed a basal diet, and the high-fiber (HF) group, which was fed the basal diet supplemented with 22.60 g/kg inulin and 181.60 g/kg cellulose. During late pregnancy, meal test, glucose tolerance test, and insulin challenge test were used to investigate the insulin sensitivity of sows, using the percutaneous brachiocephalic vein catheterization technique. High DF consumption resulted in improved insulin sensitivity, especially during the second and third trimesters, and promoted serotonin production from tryptophan. Additionally, plasma serotonin concentration was positively correlated with the insulin sensitivity index during late pregnancy. Moreover, DF consumption elevated fecal short-chain fatty acid (SCFA) concentrations, altered fecal microbial diversity, and increased the abundances of Rikenellaceae_RC9_gut_group, Alloprevotella, Parabacteroides, Roseburia, and Sphaerochaeta, which were positively correlated to plasma serotonin concentration.ConclusionsDF consumption improved insulin sensitivity during late pregnancy in sows, which improved microbial diversity in fecal samples and increased fecal SCFA concentrations, resulting in a positive correlation with plasma serotonin level.

Faecal Short-Chain, Long-Chain, and Branched-Chain Fatty Acids as Markers of Different Chronic Inflammatory Enteropathies in Dogs

Chronic inflammatory enteropathies (CIEs) are classified based on treatment trials, and new methods are being sought for earlier differentiation and characterization. Giardia infection (GIA) is one of the first differential diagnoses and may be present in CIE-affected dogs. The aim of this study was to evaluate the faecal characteristics and faecal fatty acid profile (short, medium, long, and branched-chain fatty acids) in dogs with food-responsive enteropathy (FRE), immunosuppressant-responsive enteropathy (IRE), and dogs infected with Giardia compared to healthy control (HC) animals as a potential non-invasive indicator of intestinal health that helps in the differentiation of CIEs. The C16:1n-7 percentage (p = 0.0001) and C16:1n-7/C16:0 ratio (p = 0.0001) served to differentiate between HC, FRE, and IRE. IRE dogs presented lower levels of short-chain fatty acids (∑SCFAs) (p = 0.0008) and acetic acid (C2) (p = 0.0007) compared to the other three groups and lower propionic acid (C3) (p = 0.0022) compared to HCs. IRE and GIA presented higher faecal fat content (p = 0.0080) and ratio of iso/anteiso branched-chain fatty acids (BCFAs) compared to HC and FRE. Correlations between some fatty acids and desaturation indices with the canine inflammatory bowel disease activity index and faecal characteristics were observed, suggesting that these compounds could play an important role in the pathogenesis of these diseases.

Effects of acupuncture on fecal short-chain fatty acids and TLR4/MyD88/NF-κB signaling pathway in spontaneously hypertensive rats

To observe the effects of acupuncture on blood pressure, fecal short-chain fatty acids (SCFAs) and toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway in spontaneously hypertensive rats (SHR), and to explore the mechanism of acupuncture for anti-hypertension. Twenty-four male SHR of SPF grade were randomly divided into a model group, a western medication group, an acupuncture group and a sham acupuncture group, with 6 rats in each group, and 6 male Wistar-Kyoto rats were selected as the blank group additionally. Hydrochlorothiazide solution was given by gavage in the western medication group; acupuncture was applied at bilateral "Renying" (ST 9) and "Zusanli" (ST 36) in the acupuncture group, 20 min a time; acupuncture was applied at the non-meridian and non-acupoint points close to bilateral "Renying" (ST 9) and "Zusanli" (ST 36) in the sham acupuncture group, 20 min a time. The intervention was adopted once a day for 4 weeks continuously in each group. The systolic blood pressure (SBP) of the caudal artery was measured before intervention and after 1, 2, 3 and 4 weeks of intervention. After intervention, the morphology of colonic tissue was observed by HE staining; the fecal level of SCFAs was detected by gas chromatography; the serum levels of interleukin (IL)-6, IL-1βand tumor necrosis factor-α (TNF-α) were detected by ELISA; the protein expression of TLR4, MyD88 and NF-κB p65 in the mesenteric artery was detected by Western blot. Compared with the blank group, in the model group, the SBP was increased (P<0.05), significant pathological changes could be found in the colonic tissue, the fecal SCFAs level was decreased (P<0.05), the serum levels of IL-6, IL-1β and TNF-α were increased (P<0.05), the protein expression of TLR4, MyD88 and NF-κB p65 in the mesenteric artery was increased (P<0.05). Compared with the model group, the SBP after 2, 3 and 4 weeks of intervention was decreased (P<0.05), the serum levels of IL-6, IL-1β and TNF-α were decreased (P<0.05) in the acupuncture group and the western medication group; the mucosal epithelium of colonic tissue was intact, the number of intestinal glands was abundant, the fecal SCFAs level was increased (P<0.05), and the protein expression of TLR4, MyD88 and NF-κB p65 in the mesenteric artery was decreased (P<0.05) in the acupuncture group. Compared with the sham acupuncture group, the SBP after 2, 3 and 4 weeks of intervention was decreased (P<0.05), the fecal SCFAs level was increased (P<0.05), the serum levels of IL-6, IL-1β and TNF-α were decreased (P<0.05), the protein expression of TLR4, MyD88 and NF-κB p65 in the mesenteric artery was decreased (P<0.05) in the acupuncture group. Acupuncture at bilateral "Renying" (ST 9) and "Zusanli" (ST 36) can effectively play an anti-hypertensive role in SHR. Its mechanism may be related to regulating fecal SCFAs level and inhibiting the TLR4/MyD88/NF-κB signaling pathway.

Impact of age-related gut microbiota dysbiosis and reduced short-chain fatty acids on the autonomic nervous system and atrial fibrillation in rats.

Aging is the most significant contributor to the increasing prevalence of atrial fibrillation (AF). Dysbiosis of gut microbiota has been implicated in age-related diseases, but its role in AF development remains unclear. This study aimed to investigate the correlations between changes in the autonomic nervous system, short-chain fatty acids (SCFAs), and alterations in gut microbiota in aged rats with AF. Electrophysiological experiments were conducted to assess AF induction rates and heart rate variability in rats. 16S rRNA gene sequences extracted from fecal samples were used to assess the gut microbial composition. Gas and liquid chromatography-mass spectroscopy was used to identify SCFAs in fecal samples. The study found that aged rats exhibited a higher incidence of AF and reduced heart rate variability compared to young rats. Omics research revealed disrupted gut microbiota in aged rats, specifically a decreased Firmicutes to Bacteroidetes ratio. Additionally, fecal SCFA levels were significantly lower in aged rats. Importantly, correlation analysis indicated a significant association between decreased SCFAs and declining heart rate variability in aged rats. These findings suggest that SCFAs, as metabolites of gut microbiota, may play a regulatory role in autonomic nervous function and potentially influence the onset and progression of AF in aged rats. These results provide novel insights into the involvement of SCFAs and autonomic nervous system function in the pathogenesis of AF. These results provide novel insights into the involvement of SCFAs and autonomic nervous system function in the pathogenesis of AF.

Levilactobacillus brevis SG031 modulates mood-related behaviors and attenuates stress-related sleep disturbance and autonomic dysfunction via gut microbiota modulation in Wistar–Kyoto rats

AimsThe probiotic bacterium Levilactobacillus brevis (L. brevis) has been proposed as a potential solution to manage mood disorders and alleviate stress-related sleep disturbances. However, the underlying mechanisms of its effects have not been fully elucidated. The aim of this study was to explore the impact and potential mechanisms of L. brevis SG031 supplementation on anxiety/depression-like behaviors and stress-induced changes in sleep patterns and sleep-related autonomic function. Main methodsMale Wistar–Kyoto rats were administered low, medium, or high doses of L. brevis SG031 or a vehicle for 4 weeks, followed by behavioral tests to evaluate anxiety and depression. After an additional 2 weeks of SG031 or vehicle administration, a cage-exchange paradigm was performed with 24-hour physiological signal measurements under different stress conditions. Fecal samples were collected to construct a 16S rRNA library and assess fecal short-chain fatty acids (SCFAs). Key findingsHigh-dose SG031 administration yielded reduced depression-like responses and enhanced social interaction in behavioral tests. It also exhibited a protective effect against stress-induced sleep disturbance characterized by decreased sleep time, increased awake time, and autonomic dysfunction during sleep. Fecal examination indicated that high-dose SG031 administration exerted beneficial effects on gut health by maintaining the gut microbial abundance, preserving stability of the microbial composition, and enriching the gut with SCFAs, which were associated with improvements in sleep and autonomic function. SignificanceThese findings collectively underscore the multifaceted potential of SG031 in addressing mental health and stress-related sleep challenges through the modulation of the gut microbiota.

Potential role of short-chain fatty acids in irritable bowel syndrome in overweight and obese individuals

Due to increasing prevalence of functional diseases of the colon in obese patients, the mechanisms by which the intestinal microbiota affects the development of symptoms of irritable bowel syndrome (IBS) in the setting of metabolic activity of adipose tissue should be investigated. The quantitative and qualitative changes in the pool of synthesized short-chain fatty acids, which have a multidirectional impact on the colonic motility is one of the key mechanisms by which the intestinal microbiota affects the occurrence and features of the course of irritable bowel syndrome. But as regards the issue of whether individual short-chain fatty acids have an impact on the severity of abdominal pain and characteristics of colonic motility dysfunction, it remains a subject of discussions. The study of the mechanisms of impact of short-chain fatty acids on the development and progression of obesity deserves special attention. Increased serum and faecal short-chain fatty acid levels in obese patients can either be a result of changes in the intestinal microflora composition associated with special eating habits and lifestyle, or have an independent effect on the development of obesity in individuals due to intestinal microflora composition disorders that have been already developed. Due to special features of the course of irritable bowel syndrome associated with overweight and obesity, studying the intestinal microbiota composition and the short-chain fatty acids produced by it in this cohort of IBS patients is of particular interest. This publication has been prepared to describe and systematize the possible mechanisms of impact of short-chain fatty acids on the development of abdominal pain and impaired colonic motility in IBS patients with overweight and obesity. The literature search was conducted in the databases Embase, PubMed and Google Scholar using the keywords “irritable bowel syndrome”, “obesity”, “short-chain fatty acids”, “gut microbiota”.

Short-chain fatty acids mitigate Methamphetamine-induced hepatic injuries in a Sigma-1 receptor-dependent manner

Methamphetamine (Meth) is a potent psychostimulant with well-established hepatotoxicity. Gut microbiota-derived short-chain fatty acids (SCFAs) have been reported to yield beneficial effects on the liver. In this study, we aim to further reveal the mechanisms of Meth-induced hepatic injuries and investigate the potential protective effects of SCFAs. Herein, mice were intraperitoneally injected with 15 mg/kg Meth to induce hepatic injuries. The composition of fecal microbiota and SCFAs was profiled using 16 S rRNA sequencing and Gas Chromatography/Mass Spectrometry (GC/MS) analysis, respectively. Subsequently, SCFAs supplementation was performed to evaluate the protective effects against hepatic injuries. Additionally, Sigma-1 receptor knockout (S1R-/-) mice and fluvoxamine (Flu), an agonist of S1R, were introduced to investigate the mechanisms underlying the protective effects of SCFAs. Our results showed that Meth activated S1R and induced hepatic autophagy, inflammation, and oxidative stress by stimulating the MAPK/ERK pathway. Meanwhile, Meth disrupted SCFAs product-related microbiota, leading to a reduction in fecal SCFAs (especially Acetic acid and Propanoic acid). Accompanied by the optimization of gut microbiota, SCFAs supplementation normalized S1R expression and ameliorated Meth-induced hepatic injuries by repressing the MAPK/ERK pathway. Effectively, S1R knockout repressed Meth-induced activation of the MAPK/ERK pathway and further ameliorated hepatic injuries. Finally, the overexpression of S1R stimulated the MAPK/ERK pathway and yielded comparable adverse phenotypes to Meth administration. These findings suggest that Meth-induced hepatic injuries relied on the activation of S1R, which could be alleviated by SCFAs supplementation. Our study confirms the crucial role of S1R in Meth-induced hepatic injuries for the first time and provides a potential preemptive therapy.

Determination of six short‐chain fatty acids in rat feces using headspace solid‐phase dynamic extraction coupled with GC‐MS

Short‐chain fatty acids (SCFAs) are organic acids with carbon atoms less than six, released through fermentation products by intestinal microbiome, having multiple physiological activities. Considering weak acidity and high volatility, derivatization or liquid–liquid extraction is essential, which is time consuming. Headspace‐solid‐phase dynamic extraction (HS‐SPDE) coupled with gas chromatography‐mass spectrometry is automated and effortless to determine SCFAs in rat feces. The extraction procedure is performed by aspirating and discharging the headspace cyclically through a steel needle, coated with an inner polyethylene glycol sorbent. The key parameters of SPDE were optimized including coating type, incubation time and temperature, and number of extraction strokes. Besides, salting‐out was conducted. Then, a method by HS‐SPDE‐GC‐MS was established and validated. It only took 3‐min incubation time, 4.5 min extraction time, and 13 min chromatographic separation in a run. The recovery, linearity, limit of quantification, and stability were evaluated. Then, the proposed method was applied to analyze rat feces including 18 rats with liver injury and 23 normal controls. Mann–Whitney U test indicated that the concentrations of six SCFAs in normal rat feces were higher than those with liver injury. This method provides a choice for fast, solvent‐free, automated, and high‐throughput analysis of SCFAs.

Limosilactobacillus fermentum TY-S11 ameliorates hypercholesterolemia via promoting cholesterol excretion and regulating gut microbiota in high-cholesterol diet-fed apolipoprotein E-deficient mice

Hypercholesterolemia is a metabolic disease characterized by elevated cholesterol level in the blood, which is a risk factor for many diseases. Probiotic intervention may be one of the ways to improve hypercholesterolemia. In this study, three strains with better cholesterol removal ability were selected from 60 strains of lactic acid bacteria, and were orally administered to apolipoprotein E-deficient mice on a high-cholesterol diet. Among the three strains, only Limosilactobacillus fermentum TY-S11, which was isolated from the intestine of a longevity person, significantly improved serum and liver lipid levels in hypercholesterolemic mice. Further study found that L. fermentum TY-S11 promoted the excretion of cholesterol in the feces and inhibited the absorption of cholesterol in the small intestine. As for gut microbiota, the results showed that L. fermentum TY-S11 not only prevented the reduction of diversity caused by high-cholesterol diet, but also increased the contents of short-chain fatty acids in feces. These results confirmed the ameliorative effect of L. fermentum TY-S11 on hypercholesterolemia.

Effects of dietary fiber and biotic supplementation on apparent total tract macronutrient digestibility and the fecal characteristics, metabolites, and microbiota of healthy adult dogs.

Dietary fibers and biotics have been shown to support gastrointestinal health in dogs, but are usually tested individually. There is value in testing fiber-biotic combinations that are commonly used commercially. Therefore, this study was conducted to determine the apparent total tract macronutrient digestibility (ATTD) of diets supplemented with fibers or biotics and to evaluate their effects on the fecal characteristics, metabolites, microbiota, and immunoglobulin A (IgA) concentrations of dogs. Twelve healthy adult female beagle dogs (age= 6.2 ± 1.6 yr; body weight = 9.5 ± 1.1kg) were used in a replicated 3 x 3 Latin square design to test three treatments: 1) control diet based on rice, chicken meal, tapioca starch, and cellulose + a placebo treat (CT); 2) diet based on rice, chicken meal, garbanzo beans, and cellulose + a placebo treat (GB); 3) diet based on rice, chicken meal, garbanzo beans, and a functional fiber/prebiotic blend + a probiotic-containing treat (GBPP). In each 28-day period, a 22-day diet adaptation was followed by a 5-day fecal collection phase. Fasted blood samples were collected on day 28. Data were analyzed using the Mixed Models procedure of SAS 9.4, with P<0.05 being significant and P<0.10 being trends. ATTD of dry matter, organic matter, and energy were lower (P<0.001) and DM fecal output was higher (P<0.01) in dogs fed GBPP than CT or GB, whereas ATTD of crude protein was higher (P<0.001) in dogs fed CT and GBPP than GB. ATTD of fat was higher (P<0.001) and wet fecal output was lower (P<0.01) in dogs fed CT than GB or GBPP. Fecal DM% was higher (P<0.001) in dogs fed CT than GBPP or GB, and higher in dogs fed GBPP than GB. Fecal short-chain fatty acid concentrations were higher (P<0.001) in dogs fed GB than CT or GBPP, and higher in dogs fed GB than GBPP. Fecal IgA concentrations were higher (P<0.01) in dogs fed GB than CT. Fecal microbiota populations were affected by diet, with alpha diversity being higher (P<0.01) in dogs fed GB than CT, and beta diversity shifting following dietary fiber and biotic supplementation. The relative abundance of 24 bacterial genera were altered in dogs fed GB or GBPP than CT. Serum triglyceride concentrations were lower in dogs fed GB than GBPP or CT. Our results demonstrate that legume-based dietary fibers, with or without prebiotics and probiotics, reduce ATTD, increase stool output, beneficially shift fecal metabolites and microbiota, and reduce blood lipids of adult dogs.

#2070 Associations of fecal and plasma levels of SCFAs with gut microbiota and clinical characteristics in non-dialysis renal anemia patients

Abstract Background and Aims Renal anemia is one of the most common complications of Chronic Kidney Disease (CKD). The gut-kidney axis hypothesis has led to numerous studies showing that patients with CKD have a distinct gut microbiota structure compared with controls and that changes in gut microbiota correlate with disease severity and progression. The short-chain fatty acids (SCFAs) are speculated to be pivotal in the gut-kidney crosstalk. However, the role of SCFAs in renal anemia has not been elucidated. This study aimed to explore and compare the fecal and plasma levels of SCFAs in non-dialysis renal anemia patients and healthy controls to reveal the potential interactions among SCFAs, gut microbiota, and clinical features of renal anemia, which may provide new light on further studies. Method A cohort of 30 non-dialysis renal anemia patients and 20 healthy controls were recruited from the First Affiliated Hospital of Zhengzhou University. Gut microbiota was analyzed using 16S rRNA gene amplification sequencing. Fecal and plasma concentrations of SCFAs were measured using GC-MS/MS platform. The clinical characteristics of patients with renal anemia and controls were evaluated. Results Renal anemia patients displayed altered microbiota composition compared to healthy subjects. The relative abundance of Enterobacterales, Enterobacteriaceae, Escherichia-Shigella, and Escherichia-coli were higher in patients with renal anemia, and the Lachnospiraceae family decreased in renal anemia patients. In contrast, the relative abundance of Lachnospirales, Lachnospiraceae, and Bacteroides vulgatus was higher in the control group. Patients with renal anemia had higher fecal and plasma concentrations of SCFAs compared to controls. The fecal and plasma concentrations of SCFAs were significantly different not only between the patients with renal anemia and controls but also in the different severity of renal anemia. Moreover, different types of SCFAs are intimately associated with clinical characteristics. The applications of medications may exert effects on the fecal and plasma SCFAs. A positive correlation was obtained between Lachnospirales and the plasma SCFAs. The levels of acetic acid and caproic acid in fecal and the levels of acetic acid, propionic acid, and butyric acid in plasma were all positively correlated with the abundance of Cyanobacteria. Conclusion The gut metabolites SCFAs are tightly linked to the alterations of gut microbiota and clinical characteristics of renal anemia. Further studies are warranted to elucidate the relationships more in-depth.

Meta-analysis of shotgun sequencing of gut microbiota in Parkinson’s disease

We aimed to identify gut microbial features in Parkinson’s disease (PD) across countries by meta-analyzing our fecal shotgun sequencing dataset of 94 PD patients and 73 controls in Japan with five previously reported datasets from USA, Germany, China1, China2, and Taiwan. GC-MS and LC-MS/MS assays were established to quantify fecal short-chain fatty acids (SCFAs) and fecal polyamines, respectively. α-Diversity was increased in PD across six datasets. Taxonomic analysis showed that species Akkermansia muciniphila was increased in PD, while species Roseburia intestinalis and Faecalibacterium prausnitzii were decreased in PD. Pathway analysis showed that genes in the biosyntheses of riboflavin and biotin were markedly decreased in PD after adjusting for confounding factors. Five out of six categories in carbohydrate-active enzymes (CAZymes) were decreased in PD. Metabolomic analysis of our fecal samples revealed that fecal SCFAs and polyamines were significantly decreased in PD. Genes in the riboflavin and biotin biosyntheses were positively correlated with the fecal concentrations of SCFAs and polyamines. Bacteria that accounted for the decreased riboflavin biosynthesis in Japan, the USA, and Germany were different from those in China1, China2, and Taiwan. Similarly, different bacteria accounted for decreased biotin biosynthesis in the two country groups. We postulate that decreased SCFAs and polyamines reduce the intestinal mucus layer, which subsequently facilitates the formation of abnormal α-synuclein fibrils in the intestinal neural plexus in PD, and also cause neuroinflammation in PD.

Bacillus siamensis Improves the Immune Status and Intestinal Health of Weaned Piglets by Improving Their Intestinal Microbiota.

Previous studies on the early interference of gut microbiota by Bacillus siamensis (B. siamensis) in weaned piglets are rarely reported, and the present trial is a preliminary study. This experiment was conducted to investigate the effects of B. siamensis supplementation on the growth performance, serum biochemistry, immune response, fecal short-chain fatty acids and microbiota of weaned piglets. Sixty weaned piglets were randomly divided into a control group (CON) and a B. siamensis group (BS), which were fed a basal diet and the basal diet supplemented with 5 × 1010 CFU B. siamensis per kg, respectively. Each group had 3 replicates and 10 piglets per replicate. The trial lasted for 28 days. The results showed that B. siamensis significantly increased the serum growth hormone (GH) and insulin-like growth factor (IGF) in piglets. Compared with the CON group, the levels of serum immunoglobulin and inflammatory factors in the BS group were significantly improved. In addition, the serum concentrations of zonulin and endotoxin (ET) in the BS group were lower. The dietary addition of B. siamensis significantly increased fecal short-chain fatty acid (SCFA) levels in piglets. Notably, B. siamensis improved the microbial composition by increasing beneficial genera, including Weissella, Lachnospiraceae_NK4A136_group and Bifidobacterium, and decreasing pathogenic genera, including Pantoea, Fusobacterium and Gemella, in piglet feces. Correlation analysis showed that the benefits of dietary B. siamensis supplementation were closely related to its improved microbial composition. In summary, the addition of B. siamensis can improve the immunity function, inflammatory response, gut permeability and SCFA levels of weaned piglets, which may be achieved through the improvement of their microbiota.

Comprehensive evaluation of the mechanism of Banxia Baizhu Tianma Decoction in ameliorating posterior circulation ischemia vertigo based on integrating fecal short-chain fatty acids and 16S rRNA sequencing

Posterior circulation ischemia vertigo (PCIV) is vertebrobasilar insufficiency resulting in vertigo. Banxia Baizhu Tianma Decoction (BBTD) is broadly applied to treat PCIV in China, but its efficacy and detailed mechanism remains unclear. Therefore, this study aims to investigate the effects of BBTD on PCIV, and identify important gut microbiota and its derived short-chain fatty acid (SCFA) changes and the detailed mechanism through 16 S rRNA sequencing with SCFAs profiling. In this study, the model of PCIV was established by surgical ligation of the right subclavian artery (RSCA) and right common carotid artery (RCCA). We found that BBTD administration effectively reduced the volume of cerebral infarction and improved neurologic functions, reduced neuronal apoptosis and neuroinflammatory. Moreover, BBTD significantly modulated the diversity and composition of the gut microbiota, including increasing the relative abundance of Lactobacillus, Prevotella and Akkermansia and decreasing relative abundances of Lachnospiraceae, Bacteroidetes (S24–7) and Ruminococcaceae. BBTD treatment also increased propionate content. Propionate mediates the the recovery of neurological functions and anti-apoptotic effects of BBTD in PCIV rat. Our findings wish to discover the potential mechanism of BBTD treatment on PCIV and promote its clinical application.

Quantifying fecal and plasma short-chain fatty acids in healthy Thai individuals

Short-chain fatty acids (SCFAs) are involved in important physiological processes such as gut health and immune response, and changes in SCFA levels can be indicative of disease. Despite the importance of SCFAs in human health and disease, reference values for fecal and plasma SCFA concentrations in healthy individuals are scarce. To address this gap in current knowledge, we developed a simple and reliable derivatization-free GC-TOFMS method for quantifying fecal and plasma SCFAs in healthy individuals. We targeted six linear- and seven branched-SCFAs, obtaining method recoveries of 73–88% and 83–134% in fecal and plasma matrices, respectively. The developed methods are simpler, faster, and more sensitive than previously published methods and are well suited for large-scale studies. Analysis of samples from 157 medically confirmed healthy individuals showed that the total SCFAs in the feces and plasma were 34.1 ± 15.3 µmol/g and 60.0 ± 45.9 µM, respectively. In fecal samples, acetic acid (Ace), propionic acid (Pro), and butanoic acid (But) were all significant, collectively accounting for 89% of the total SCFAs, whereas the only major SCFA in plasma samples was Ace, constituting of 93% of the total plasma SCFAs. There were no statistically significant differences in the total fecal and plasma SCFA concentrations between sexes or among age groups. The data revealed, however, a positive correlation for several nutrients, such as carbohydrate, fat, iron from vegetables, and water, to most of the targeted SCFAs. This is the first large-scale study to report SCFA reference intervals in the plasma and feces of healthy individuals, and thereby delivers valuable data for microbiome, metabolomics, and biomarker research.