Fecal Short-chain Fatty Acid Concentrations Research Articles

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 ± 45.9µM, 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.

Green banana biomass anti-obesogenic, anti-hyperlipidemic, antidiabetic, and intestinal function potential effects: a systematic review.

Apparently, the consumption of resistant-starch food sources, such as green banana biomass, stimulates the proliferation of short-chain fatty acid intestinal bacteria producers, which can contribute to intestinal health and reduce the risk of chronic diseases. However, the available scientific evidence is scarce and no study has systematically evaluated such evidence. The aim of this study was to analyze the potential effects of green banana biomass on anthropometry, body composition, and biochemical and intestinal variables in humans and animals. The Cochrane Library, Embase, Medline/PubMed, Scopus, and Web of Science electronic databases were searched in January 2024 for eligible articles. Studies that tested the effects of cooked peeled or unpeeled green banana on anthropometric, biochemical, and/or intestinal variables were included. This systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The classification and assessment of the quality of studies were based on the relevant criteria related to the design of these studies and the quality criteria checklist of the Academy of Nutrition and Dietetics manual. Twelve studies published between 2001 and 2021 were included in the review. The results of human studies indicate that the ingestion of green banana biomass controlled intestinal dysfunction (50-300 g/day for 5-14 days or 30 g/day for 8 wk) in children, and showed potential anti-obesogenic, anti-hyperlipidemic, and antidiabetic (40 g/day for 24 wk) effects in adults. In rats, biomass consumption led to potential anti-obesogenic (25 g/day for 8 wk), anti-hyperlipidemic, and antidiabetic (∼8-30 g/day for 12 wk) effects. Consumption of green banana biomass seems to exert beneficial effects on intestinal function and potential effects on obesity, dyslipidemia, and diabetes. These effects may be related to increased fecal short-chain fatty acid concentrations as a result of type 3 resistant starch present in biomass. Open Science Framework (OSF) (https://doi.org/10.17605/OSF.IO/TKCWV).

Fibras solúvel e insolúvel em dietas de leitões na creche

This study evaluated the effect of diets containing low levels of soluble and insoluble fiber sources on performance, diarrhea score, chemical and physical characteristics of feces, and behavior in weaning piglets. Thirty-six weaned piglets of 30 days of age with an initial body weight of 8.8 kg were distributed in 36 pens using a completely randomized design in an experimental period of 21 days. The experimental treatments were the Control diet (CONT), the Control diet + 1% beet pulp inclusion (SBP), and the Control diet + 1% lignocellulose inclusion (LCE, Arbocel®). Feed and water were available ad libitum. Body weight and feed intake were measured weekly to calculate the average daily intake, weight gain, and feed conversion ratio. The fecal consistency was determined visually twice daily, classifying feces according to three scores. To determine fecal pH and concentration of fecal short-chain fatty acids (SCFA), samples of fresh feces were collected two weeks after weaning and measured by a digital pH meter and gas chromatography, respectively. The behavior of piglets was observed once a week, using four animals per treatment, from 14:00 to 16:00, every 12 min. Fibre sources had no effect (P>0.05) on performance, except in the period 15 to 21 days after weaning, which was a tendency (P=0.061) of feed intake decrease in SBP and LCE diets. Fiber sources did not affect the fecal consistency score (P>0.05). However, piglets fed SBP and LCE showed a tendency (P<0.10) to have less diarrhea incidence 15 to 21 days post-weaning and in the entire experimental period. Fecal pH and SCFA concentration were not influenced by fiber source (P>0.05), with acetic, propionic, and butyric acids representing around 71%, 19%, and 10% of the total, respectively. Fiber sources did not influence the social and feeding behavior of weaning piglets (P>0.05). Diets containing 1% fiber sources did not alter performance, diarrhea score, fecal pH, fecal SCFA concentration, or feeding and social behavior of weaned piglets.

Protective effect of chicken yolk antibody Y against Campylobacter jejuni induced diarrhea in cats.

Campylobacter jejuni (C. jejuni) is a common pathogen that often causes diarrhea, loss of appetite, and even enteritis in domestic cats, affecting their growth and development, especially in kittens under 6 months of age. Oral passive immunization with chicken yolk antibody Y has been proved effective for the treatment of gastrointestinal pathogen infections due to its high specificity. In this study, C. jejuni was isolated from diarrheal cat feces, and the specific egg yolk antibody Y against C. jejuni was demonstrated to effectively inhibit its proliferation in vitro experiments. To evaluate the effect of anti-C. jejuni IgY, the mouse C. jejuni infection model was established and it was found that IgY could alleviate C. jejuni-induced clinical symptoms. Consistent with these results, the reduction of pro-inflammatory factors and intestinal colonization by C. jejuni in the IgY-treated groups, especially in the high dose group. We then evaluated the protective effect of IgY on young Ragdoll cats infected with C. jejuni. This specific antibody reduced the rate of feline diarrhea, protected the growth of young cats, inhibited systemic inflammatory hyperactivation, and increased fecal short-chain fatty acid concentrations. Notably, IgY may have a protective role by changing intestinal amino acid metabolism and affecting C. jejuni chemotaxis. Collectively, specific IgY is a promising therapeutic strategy for C. jejuni-induced cat diarrhea.

XX sex chromosome complement modulates immune responses to heat-killed Streptococcus pneumoniae immunization in a microbiome-dependent manner.

Differences in male vs. female immune responses are well-documented and have significant clinical implications. While the immunomodulatory effects of sex hormones are well established, the contributions of sex chromosome complement (XX vs. XY) and gut microbiome diversity on immune sexual dimorphisms have only recently become appreciated. Here we investigate the individual and collaborative influences of sex chromosome complements and gut microbiota on humoral immune activation. Male and female Four Core Genotype (FCG) mice were immunized with heat-killed Streptococcus pneumoniae (HKSP). Humoral immune responses were assessed, and X-linked immune-related gene expression was evaluated to explain the identified XX-dependent phenotype. The functional role of Kdm6a, an X-linked epigenetic regulatory gene of interest, was evaluated ex vivo using mitogen stimulation of B cells. Additional influences of the gut microbiome on sex chromosome-dependent B cell activation was also evaluated by antibiotically depleting gut microbiota prior to HKSP immunization. Reconstitution of the depleted microbiome with short-chain fatty acid (SCFA)-producing bacteria tested the impact of SCFAs on XX-dependent immune activation. XX mice exhibited higher HKSP-specific IgM-secreting B cells and plasma cell frequencies than XY mice, regardless of gonadal sex. Although Kdm6a was identified as an X-linked gene overexpressed in XX B cells, inhibition of its enzymatic activity did not affect mitogen-induced plasma cell differentiation or antibody production in a sex chromosome-dependent manner ex vivo. Enhanced humoral responses in XX vs. XY immunized FCG mice were eliminated after microbiome depletion, indicating that the microbiome contributes to the identified XX-dependent immune enhancement. Reconstituting microbiota-depleted mice with select SCFA-producing bacteria enhanced fecal SCFA concentrations and increased humoral responses in XX, but not XY, FCG mice. However, exposure to the SCFA propionate alone did not enhance mitogenic B cell stimulation in ex vivo studies. FCG mice have been used to assess sex hormone and sex chromosome complement influences on various sexually dimorphic traits. The current study indicates that the gut microbiome impacts humoral responses in an XX-dependent manner, suggesting that the collaborative influence of gut bacteria and other sex-specific factors should be considered when interpreting data aimed at delineating the mechanisms that promote sexual dimorphism.

Association of short-chain fatty acids and the gut microbiome with type 2 diabetes: Evidence from the Henan Rural Cohort

Background and aimsHuman studies about short-chain fatty acids (SCFAs), the gut microbiome, and Type 2 diabetes (T2DM) are limited. Here we explored the association between SCFAs and T2DM and the effects of gut microbial diversity on glucose status in rural populations. Methods and resultsWe performed a cross-sectional study from the Henan Rural Cohort and collected stool samples. Gut microbiota composition and faecal SCFA concentrations were measured by 16S rRNA and GC-MS. The population was divided based on the tertiles of SCFAs, and logistic regression models assessed the relationship between SCFAs and T2DM. Generalized linear models tested the interactions between SCFAs and gut microbial diversity on glucose indicators (glucose, HbAlc and insulin). Compared to the lowest tertile of total SCFA, acetate and butyrate, the highest tertile exhibited lower T2DM prevalence, with ORs and 95% CIs of 0.291 (0.085–0.991), 0.160 (0.044–0.574) and 0.171 (0.047–0.620), respectively. Restricted cubic spline demonstrated an approximately inverse S-shaped association. We also noted interactions of the ACE index with the highest tertile of valerate on glucose levels (P-interaction = 0.022) and the Shannon index with the middle tertile of butyrate on insulin levels (P-interaction = 0.034). Genus Prevotella_9 and Odoribacter were inversely correlated with T2DM, and the genus Blautia was positively associated with T2DM. These bacteria are common SCFA-producing members. ConclusionsInverse S-shaped associations between SCFAs (total SCFA, acetate, and butyrate) and T2DM were observed. Valerate and butyrate modify glucose status with increasing gut microbial diversity.

Вікові особливості перебігу ротавірусної інфекції в дітей та внесок осмотичного компонента в патогенез діарейного синдрому залежно від віку

Purpose - to identify the age-specific features of the course of rotavirus infection (RVI) in children and to clarify the role of the osmolar component in the pathogenesis of diarrheal syndrome in young children. Materials and methods. 100 young children with RVI were examined. Children were divided into 3 age subgroups: 1-6 months, 6-12 months and 13-24 months. A comparative analysis of the manifestation and features of the clinical course of the disease was carried out in the subgroups. A comparative assessment of the level of undigested sugars in feces and concentrations of short-chain fatty acids (SCFA) in the dynamics of the disease were carried out. The total level of carbohydrates in feces was determined on the 2nd, 5th, 7th and 10th day of RVI using the Benedict test. Concentrations of SCFA (acetate, propionate, butyrate) were determined on 2nd, 5th and 10th days by liquid chromatography. As physiological indicators of the total amount of carbohydrates in the feces and fecal concentrations of SCFA, the indicators of 30 relatively healthy children were taken. The "STATISTICA for Windows 13" program was used for statistical processing of the obtained data. Since the quantitative values that were analyzed had a distribution that differed from normal, non-parametric statistical methods were applied. Results. Children 1-6 months of age with RVI less often had fever and vomiting (p˂0.05), had longer diarrhea (p˂0.05), which was more often accompanied by flatulence, intestinal colic (p˂0.05), than children 13-24 months of age. Children of this subgroup had the highest levels of carbohydrates in feces in the acute period of RVI (р˂0.05 on the 2nd and 5th day relative to children 6-12 months and 13-24 months of age) and in the period of convalescence (р˂0.05 on 10th day for children 13-24 months of age). In all subgroups of children, reduced concentrations of SCFA were noted in the acute period of RVI (p>0.05 relative to the reference values from the 3rd to the 5th day). The most pronounced decrease in the total concentrations of SCFA (p<0.01 relative to the reference values) during the entire period of RVI were observed in children 1-6 months of aged. Conclusions. RVI is characterized by longer diarrhea which is more often accompanied by flatulence and intestinal colic in children 1-6 months of age, while children 13-24 months of age more often have fever and vomiting. The most pronounced disturbances of carbohydrate metabolism in the intestines and changes in the functional activity of the intestinal microflora during RVI occur in children 1-6 months of age. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Alteration of gut microbiota in post-stroke depression patients with Helicobacter pylori infection

Background: Several studies have identified an association between the gut microbiome and post-stroke depression(PSD), and Helicobacter pylori(H. pylori) infection cause significant alterations in the composition of the gastrointestinal microbiome. However, evidence regarding the role of the H. pylori infection in promoting PSD is still lacking. Here, we conducted a retrospective study to explore risk factors associated with PSD.Methods: Patients with cerebral infarction were consecutively enrolled from December 2021 to October 2022. The diagnosis of PSD is based on the DSM-V criteria, and the Hamilton Depression Rating Scale(HAMD) was used to identify patients with PSD. White matter lesions were evaluated using magnetic resonance imaging(MRI) and H. pylori infection was detected by 13C-urea breath test. Further, 16S rRNA gene sequencing was used to evaluate the changes in gut microbiota composition of fecal samples from PSD patients. The concentration of short-chain fatty acids(SCFAs) was determined by gas chromatography–mass spectrometry(GC–MS).Results: Multivariate regression analysis showed that deep white matter lesions(DWMLs) [odds ratio(OR) 3.382, 95% confidence interval(CI) 1.756–6.512; P = 0.001] and H. pylori infection(OR 2.186, 95% CI 1.149–4.159; P = 0.017) were the independent risk factors for PSD. Patients with H. pylori infection had more severe depressive symptoms than patients without infection. Intestinal microbiota was significantly different between H. pylori-positive PSD[H. pylori(+)] patients and H. pylori-negative PSD[H. pylori (−)] patients. Fecal SCFAs concentrations were significantly reduced in the H. pylori(+) group compared to the negative ones.Conclusion: DWMLs and H. pylori infection may play important roles in the development of PSD. H. pylori infection is likely to be involved in the pathogenesis of PSD by altering the intestinal flora.

Comparison of a Daily Steviol Glycoside Beverage compared with a Sucrose Beverage for Four Weeks on Gut Microbiome in Healthy Adults

BackgroundRecent studies suggest that some nonnutritive sweeteners (NNS) have deleterious effects on the human gut microbiome (HGM). The effect of steviol glycosides on the HGM has not been well studied. ObjectiveWe aimed to evaluate the effects of stevia- compared with sucrose-sweetened beverages on the HGM and fecal short-chain fatty acid (SCFA) profiles. MethodsUsing a randomized, double-blinded, parallel-design study, n = 59 healthy adults [female/male, n = 36/23, aged 31±9 y, body mass index (BMI): 22.6±1.7 kg/m2] consumed 16 oz of a beverage containing either 25% of the acceptable daily intake (ADI) of stevia or 30 g of sucrose daily for 4 weeks followed by a 4-week washout. At weeks 0 (baseline), 4, and 8, the HGM was characterized via shotgun sequencing, fecal SCFA concentrations were measured using ultra-high performance liquid chromatography-tandem mass spectrometry and anthropometric measurements, fasting serum glucose, insulin and lipids, blood pressure, pulse, and 3-d diet records were obtained. ResultsThere were no significant differences in the HGM or fecal SCFA between the stevia and sucrose groups at baseline (P > 0.05). At week 4 (after intervention), there were no significant differences in the HGM at the phylum, family, genus, or species level between the stevia and sucrose groups and no significant differences in fecal SCFA. At week 4, BMI had increased by 0.3 kg/m2 (P = 0.013) in sucrose compared with stevia, but all other anthropometric and cardiometabolic measures and food intake did not differ significantly (P > 0.05). At week 8 (after washout), there were no significant differences in the HGM, fecal SFCA, or any anthropometric or cardiometabolic measure between the stevia and sucrose groups (P > 0.05). ConclusionsDaily consumption of a beverage sweetened with 25% of the ADI of stevia for 4 weeks had no significant effects on the HGM, fecal SCFA, or fasting cardiometabolic measures, compared with daily consumption of a beverage sweetened with 30 g of sucrose. Trial registrationclinicaltrials.gov as NCT05264636

Dual role for microbial short-chain fatty acids in modifying SIV disease trajectory following anti-α4β7 antibody administration

Background Human Immunodeficiency Virus (HIV)/Simian Immunodeficiency Virus (SIV) infection is associated with significant gut damage, similar to that observed in patients with inflammatory bowel disease (IBD). This pathology includes loss of epithelial integrity, microbial translocation, dysbiosis, and resultant chronic immune activation. Additionally, the levels of all-trans-retinoic acid (atRA) are dramatically attenuated. Data on the therapeutic use of anti-α4β7 antibodies has shown promise in patients with ulcerative colitis and Crohn’s disease. Recent evidence has suggested that the microbiome and short-chain fatty acid (SCFA) metabolites it generates may be critical for anti-α4β7 efficacy and maintaining intestinal homeostasis. Materials and Methods To determine whether the microbiome contributes to gut homeostasis after anti-α4β7 antibody administered to SIV-infected rhesus macaques, faecal SCFA concentrations were determined, 16S rRNA sequencing was performed, plasma viral loads were determined, plasma retinoids were measured longitudinally, and gut retinoid synthesis/response gene expression was quantified. Results Our results suggest that anti-α4β7 antibody facilitates the return of retinoid metabolism to baseline levels after SIV infection. Furthermore, faecal SCFAs were shown to be associated with retinoid synthesis gene expression and rebound viral loads after therapy interruption. Conclusions Taken together, these data demonstrate the therapeutic advantages of anti-α4β7 antibody administration during HIV/SIV infection and that the efficacy of anti-α4β7 antibody may depend on microbiome composition and SCFA generation.

Impact of fibre supplementation on microbiome and resilience in healthy participants: A randomized, placebo-controlled clinical trial

Background and aimsThe gut microbiome exerts important roles in health, e.g., functions in metabolism and immunology. These functions are often exerted via short-chain fatty acid (SCFA) production by gut bacteria. Studies demonstrating causal relationships between interventions targeting the microbiome and clinical outcomes are limited. This study aimed to show a causal relationship between microbiome modulation through fibre intervention and health. Methods and resultsThis randomized, double-blind, cross-over study included 65 healthy subjects, aged 45–70 years, with increased metabolic risk (i.e., body mass index [BMI] 25–30 kg/m2, low to moderate daily dietary fibre intake, <30g/day). Subjects took daily a fibre mixture of Acacia gum and carrot powder or placebo for 12 weeks, with an 8-week wash-out period. Faecal samples for measurement of SCFAs and microbiome analysis were collected every 4 weeks. Before and after each intervention period subjects underwent the mixed-meal PhenFlex challenge Test (PFT). Health effects were expressed as resilience to the stressors of the PFT and as fasting metabolic and inflammatory state. The fibre mixture exerted microbiome modulation, with an increase in β-diversity (p < 0.001). α-diversity was lower during fibre mixture intake compared to placebo after 4, 8 and 12 weeks (p = 0.002; p = 0.012; p = 0.031). There was no effect observed on faecal SCFA concentrations, nor on any of the primary clinical outcomes (Inflammatory resilience: p = 0.605, Metabolic resilience: p = 0.485). ConclusionAlthough the intervention exerted effects on gut microbiome composition, no effects on SCFA production, on resilience or fasting metabolic and inflammatory state were observed in this cohort. Registration number Clinicaltrials.govNCT04829396.

Alteration in the gut microbiome is associated with changes in bone metabolism after laparoscopic sleeve gastrectomy.

Laparoscopic sleeve gastrectomy (LSG), the most common bariatric surgical procedure, leads to durable weight loss and improves obesity-related comorbidities. However, it induces abnormalities in bone metabolism. One unexplored potential contributor is the gut microbiome, which influences bone metabolism and is altered after surgery. We characterized the relationship between the gut microbiome and skeletal health in severe obesity and after LSG. In a prospective cohort study, 23 adults with severe obesity underwent skeletal health assessment and stool collection preoperatively and 6mo after LSG. Gut microbial diversity and composition were characterized using 16S rRNA gene sequencing, and fecal concentrations of short-chain fatty acids (SCFA) were measured with LC-MS/MS. Spearman's correlations and PERMANOVA analyses were applied to assess relationships between the gut microbiome and bone health measures including serum bone turnover markers (C-terminal telopeptide of type 1 collagen [CTx] and procollagen type 1N-terminal propeptide [P1NP]), areal BMD, intestinal calcium absorption, and calciotropic hormones. Six months after LSG, CTx and P1NP increased (by median 188% and 61%, P< .01) and femoral neck BMD decreased (mean -3.3%, P< .01). Concurrently, there was a decrease in relative abundance of the phylum Firmicutes. Although there were no change in overall microbial diversity or fecal SCFA concentrations after LSG, those with greater within-subject change in gut community microbial composition (β-diversity) postoperatively had greater increases in P1NP level (ρ= 0.48, P= .02) and greater bone loss at the femoral neck (ρ= -0.43, P= .04). In addition, within-participant shifts in microbial richness/evenness (α-diversity) were associated with changes in IGF-1 levels (ρ= 0.56, P< .01). The lower the postoperative fecal butyrate concentration, the lower the IGF-1 level (ρ= 0.43, P= .04). Meanwhile, the larger the decrease in butyrate concentration, the higher the postoperative CTx (ρ= -0.43, P= .04). These findings suggest that LSG-induced gut microbiome alteration may influence skeletal outcomes postoperatively, and microbial influences on butyrate formation and IGF-1 are possible mechanisms.

Dietary intervention with edible film-coated multistrain probiotic Lacticaseibacilli in nondairy food matrices significantly increased the recovery of fecal viable Lacticaseibacilli and improved the performance of several colonic biomarkers among slightly malnourished preschool children.

Probiotic enriched dairy products are widely consumed in Western countries for their beneficial effects on the gastrointestinal tract and overall health. The present study aims to investigate the beneficial effects of probiotic Lacticaseibacilli (LAB) strains in non-dairy food matrices. A blend of edible film-coated probiotic LAB, L. plantarum, L. paracasei, and L. rhamnosus, were incorporated into plain biscuits and dry dates. Design of the randomized controlled study: Children of both sexes (mean age 55.7 ± 14.5 months) attending kindergarten in Tersa, a poor urban Giza district, were recruited and randomized into 5 groups of equal numbers. Treatment groups: (1) placebo biscuits, (2) functional probiotic biscuits (0.18 billion colony forming units (cfu) of LAB) (3) functional probiotic + inulin biscuits (0.2 billion cfu of LAB + 2 g of chicory inulin); (4) placebo dates and (5) functional probiotic dates (0.3 billion cfu of viable multistrain LAB). The supplements were served 5 days a week and each child had to consume 21 servings of the supplement. The primary outcome was an increase in the fecal recovery of viable LAB after the intake of 21 servings (T1) compared to the respective baseline counts (T0). The secondary outcomes include the determination of fecal short-chain fatty acids (SCFA) and secretory immunoglobulin A (s-Ig A) using ELISA and fecal ammonia excretion. Results: Statistically significant % increases in the recoveries of fecal viable LAB were found among the children consuming 21 servings of supplements 2, 3, and 5 compared to the respective count at T0. Similar significant increases were found in the fecal concentrations of SCFA and s-Ig A among the children consuming 21 servings of supplements 2, 3 and 5 compared to the respective counts at T0. On the other hand, the concentration of toxic ammonia excretion decreased significantly in the feces of all children consuming probiotic-containing supplements (groups 2, 3, and 5) at T1 compared to the respective concentrations obtained at T0. Conclusion: Multistrain microencapsulated probiotic Lacticaseibacilli in functional biscuits and dry dates successfully tolerated the acidic gastric transit and exerted their bioactive action on the colonic microbiome. The synbiotic supplement exhibited a higher production rate of colonic SCFA. Probiotic-enriched products that confer definitive health benefits are convenient and do not need to be kept under refrigeration. Manipulating the composition and function of the microbiome in childhood through probiotic/+ prebiotic interventions is cost-effective with long-term beneficial health outcomes. This study was approved by the Medical Research Ethics Committee, National Research Center and registered as Clinical Trial 16/422. Written informed consent was obtained from the mothers of all participating children.

Dose-Dependent Effects of Supplementing a Two-Strain Bacillus subtilis Probiotic on Growth Performance, Blood Parameters, Fecal Metabolites, and Microbiome in Nursery Pigs.

This experiment was conducted to evaluate the effects of dietary supplementation level of a two-strain Bacillus subtilis probiotic on growth performance, blood parameters, fecal metabolites, and microbiome in nursery pigs. A total of 54 weaned piglets were allotted to three treatments in three replicate pens with six pigs/pen for a 28 d feeding trial. The treatments were as follows: control: no probiotic supplementation; Pro1x: B. subtilis supplementation at 1.875 × 105 CFU/g diet; and Pro10x: B. subtilis supplementation at 1.875 × 106 CFU/g diet. Body weight at d 14 postweaning (p = 0.06) and average daily gain for d 0 to 14 postweaning (p < 0.05) were greater in the Pro1x treatment than in the other treatments. Blood glucose levels were greater in both probiotic treatments than in the control treatment at d 14 postweaning (p < 0.05). In the fecal short-chain fatty acid (SCFA) concentrations, the butyrate concentrations were greater in the Pro1x treatment than in the other treatments (p < 0.05), and the acetate, propionate, and total SCFA concentrations were greater in the Pro1x treatment than in the Pro10x treatment (p < 0.05). The beta diversity of fecal microbiome composition at d 14 postweaning based on Unweighted Unifrac analysis was dissimilar between the Pro1x and Pro10x treatments (p < 0.05). In conclusion, dietary B. subtilis supplementation of two strains selected to reduce effects of pathogenic Escherichia coli to nursery diets at 1.875 × 105 CFU/g diet improved the growth rate in the early postweaning period, increased fecal SCFA concentrations and altered the fecal microbial community composition. A higher dose of B. subtilis did not improve the performance parameters over those of the control piglets.

The gut-lung axis in critical illness: microbiome composition as a predictor of mortality at day 28 in mechanically ventilated patients

BackgroundMicrobial communities are of critical importance in the human host. The lung and gut microbial communities represent the most essential microbiota within the human body, collectively referred to as the gut-lung axis. However, the differentiation between these communities and their influence on clinical outcomes in critically ill patients remains uncertain.MethodsAn observational cohort study was obtained in the intensive care unit (ICU) of an affiliated university hospital. Sequential samples were procured from two distinct anatomical sites, namely the respiratory and intestinal tracts, at two precisely defined time intervals: within 48 h and on day 7 following intubation. Subsequently, these samples underwent a comprehensive analysis to characterize microbial communities using 16S ribosomal RNA (rRNA) gene sequencing and to quantify concentrations of fecal short-chain fatty acids (SCFAs). The primary predictors in this investigation included lung and gut microbial diversity, along with indicator species. The primary outcome of interest was the survival status at 28 days following mechanical ventilation.ResultsSixty-two mechanically ventilated critically ill patients were included in this study. Compared to the survivors, the diversity of microorganisms was significantly lower in the deceased, with a significant contribution from the gut-originated fraction of lung microorganisms. Lower concentrations of fecal SCFAs were detected in the deceased. Multivariate Cox regression analysis revealed that not only lung microbial diversity but also the abundance of Enterococcaceae from the gut were correlated with day 28 mortality.ConclusionCritically ill patients exhibited lung and gut microbial dysbiosis after mechanical ventilation, as evidenced by a significant decrease in lung microbial diversity and the proliferation of Enterococcaceae in the gut. Levels of fecal SCFAs in the deceased served as a marker of imbalance between commensal and pathogenic flora in the gut. These findings emphasize the clinical significance of microbial profiling in predicting the prognosis of ICU patients.

An open-label pilot single-subject study to monitor the impact of a Food-Based enteral formula on faecal short-chain fatty acid concentrations in children admitted to intensive care with sepsis

An open-label pilot single-subject study to monitor the impact of a Food-Based enteral formula on faecal short-chain fatty acid concentrations in children admitted to intensive care with sepsis

Associations of Plastic Bottle Exposure with Infant Growth, Fecal Microbiota, and Short-Chain Fatty Acids.

Murine models show that plastics, via their chemical constituents (e.g., phthalates), influence microbiota, metabolism, and growth. However, research on plastics in humans is lacking. Here, we examine how the frequency of plastic bottle exposure is associated with fecal microbiota, short-chain fatty acids (SCFAs), and anthropometry in the first year of life. In 442 infants from the prospective Nurture birth cohort, we examined the association of frequency of plastic bottle feeding at 3 months with anthropometric outcomes (skinfolds, length-for-age, and weight-for-length) at 12 months of age and growth trajectories between 3 and 12 months. Furthermore, in a subset of infants (n = 70) that contributed fecal samples at 3 months and 12 months of age, we examined plastic bottle frequency in relation to fecal microbiota composition and diversity (measured by 16S rRNA gene sequencing of V4 region), and fecal SCFA concentrations (quantified using gas chromatography mass spectrometry). At 3 months, 67.6% of infants were plastic bottle fed at every feeding, 15.4% were exclusively breast milk fed, and 48.9% were exclusively formula fed. After adjustment for potential confounders, infants who were plastic bottle fed less than every feeding compared to those who were plastic bottle fed at every feeding at 3 months did not show differences in anthropometry over the first 12 months of life, save for lower length-for-age z-score at 12 months (adjusted β = -0.45, 95% CI: -0.76, -0.13). Infants who were plastic bottle fed less than every feeding versus every feeding had lower fecal microbiota alpha diversity at 3 months (mean difference for Shannon index: -0.59, 95% CI: -0.99, -0.20) and lower isovaleric acid concentration at 3 months (mean difference: -2.12 μmol/g, 95% CI: -3.64, -0.60), but these results were attenuated following adjustment for infant diet. Plastic bottle frequency was not strongly associated with microbiota diversity or SCFAs at 12 months after multivariable adjustment. Frequency of plastic bottle use was associated with differential abundance of some bacterial taxa, however, significance was not consistent between statistical approaches. Plastic bottle frequency at 3 months was not strongly associated with measures of adiposity or growth (save for length-for-age) over the first year of life, and while plastic bottle use was associated with some features of fecal microbiota and SCFAs in the first year, these findings were attenuated in multivariable models with infant diet. Future research is needed to assess health effects of exposure to other plastic-based products and objective measures of microplastics and plastic constituents like phthalates.

Systemic but not fecal short-chain fatty acid (SCFA) concentrations reflect intestinal SCFA production as assessed by novel stable isotope method

Systemic but not fecal short-chain fatty acid (SCFA) concentrations reflect intestinal SCFA production as assessed by novel stable isotope method

Impaired gut microbiota-mediated short-chain fatty acid production precedes morbidity and mortality in people with HIV

Antiretroviral therapy (ART) has dramatically lengthened lifespan among people with HIV (PWH), but this population experiences heightened rates of inflammation-related comorbidities. HIV-associated inflammation is linked with an altered microbiome; whether such alterations precede inflammation-related comorbidities or occur as their consequence remains unknown. We find that ART-treated PWH exhibit depletion of gut-resident bacteria that produce short-chain fatty acids (SCFAs)-crucial microbial metabolites with anti-inflammatory properties. Prior reports establish that fecal SCFA concentrations are not depleted in PWH. We find that gut-microbiota-mediated SCFA production capacity is better reflected in serum than in feces and that PWH exhibit reduced serum SCFA, which associates with inflammatory markers. Leveraging stool and serum samples collected prior to comorbidity onset, we find that HIV-specific microbiome alterations precede morbidity and mortality in ART-treated PWH. Among these microbiome alterations, reduced microbiome-mediated conversion of lactate to propionate precedes mortality in PWH. Thus, gut microbial fiber/lactate conversion to SCFAs may modulate HIV-associated comorbidity risk.

32 Effect of Probiotics Supplementation Level on Growth Performance, Blood Parameters and Fecal Metabolites in Nursery Pigs

Abstract This experiment was conducted to evaluate the effects of dietary supplementation level of probiotics on growth performance, blood variables, and fecal metabolites in nursery pigs. Certain strains of Bacillus subtilis have been shown to reduce the incidence and severity of diarrhea and therefore improve growth performance of nursery pigs. A total of 54 newly weaned piglets were allotted to 3 treatments in 3 replicates with 6 pigs per pen based on body weight, gender, and breed for a 28-d feeding trial. Treatments were: 1) Control: no probiotics supplementation, 2) CERTILLUS 1x: probiotics supplementation at the recommended level, and 3) CERTILLUS 10x: probiotics supplementation at 10 times the recommended level. The CERTILLUS products consisted of two strains of Bacillus subtilis at a low and a high dose of 3.75 × 108 CFU/g and 3.75 × 109 CFU/g supplemented at 0.05% resulting in 1.875 × 105 CFU/g diet and 1.875 × 106 CFU/g diet for the 1x and 10x treatments, respectively. Corn-soybean meal-based diets were used for d 0-14 (Phase 1) and d 14-28 (Phase 2) postweaning. Body weight, blood glucose and creatinine, fecal short chain fatty acid (SCFA) and bile acid concentrations were measured at d 14 and 28 postweaning. Body weight at d 14 postweaning (P = 0.06; 11.98, 12.73, and 12.21 kg for the control, 1x, and 10x treatments, respectively) and average daily gain for d 0 to 14 postweaning (P &amp;lt; 0.05; 0.206, 0.259, and 0.222 kg/d, respectively) were greater in the 1x treatment than the control and 10x treatments although there was no significant difference in growth performance at d 28 postweaning. Blood glucose concentrations were greater in both probiotic treatments than the control treatment at d 14 postweaning (P &amp;lt; 0.05; 95.2, 111.7 and 114.3 mg/dL for the control, 1x, and 10x treatments, respectively). In the fecal SCFA concentrations, the butyrate concentrations were greater in the 1x treatment than the control and 10x treatments (P &amp;lt; 0.05; 36.17, 47.57, and 33.23 µmol/g feces for the control, 1x, and 10x treatments, respectively) and the acetate (120.02, 141.87, and 101.17 µmol/g feces, respectively), propionate (62.95, 71.42 and 55.27 µmol/g feces, respectively), and total SCFA (236.72, 282.23, and 205.80 µmol/g feces, respectively) concentrations were greater in the 1x treatment than the 10x treatment with the intermediate value in the control treatment (P &amp;lt; 0.05). There were no significant differences in fecal bile acid concentrations and blood creatinine concentrations at both d 14 and 28 postweaning. In conclusion, dietary probiotics supplementation to nursery diets at the recommended level could improve growth rate in the early postweaning period and increase fecal SCFA concentrations but not at a high level of supplementation.