Ratios Of Short Chain Fatty Acids Research Articles

Gut barrier-microbiota imbalances in early life lead to higher sensitivity to inflammation in a murine model of C-section delivery

BackgroundMost interactions between the host and its microbiota occur at the gut barrier, and primary colonizers are essential in the gut barrier maturation in the early life. The mother–offspring transmission of microorganisms is the most important factor influencing microbial colonization in mammals, and C-section delivery (CSD) is an important disruptive factor of this transfer. Recently, the deregulation of symbiotic host-microbe interactions in early life has been shown to alter the maturation of the immune system, predisposing the host to gut barrier dysfunction and inflammation. The main goal of this study is to decipher the role of the early-life gut microbiota-barrier alterations and its links with later-life risks of intestinal inflammation in a murine model of CSD.ResultsThe higher sensitivity to chemically induced inflammation in CSD mice is related to excessive exposure to a too diverse microbiota too early in life. This early microbial stimulus has short-term consequences on the host homeostasis. It switches the pup’s immune response to an inflammatory context and alters the epithelium structure and the mucus-producing cells, disrupting gut homeostasis. This presence of a too diverse microbiota in the very early life involves a disproportionate short-chain fatty acids ratio and an excessive antigen exposure across the vulnerable gut barrier in the first days of life, before the gut closure. Besides, as shown by microbiota transfer experiments, the microbiota is causal in the high sensitivity of CSD mice to chemical-induced colitis and in most of the phenotypical parameters found altered in early life. Finally, supplementation with lactobacilli, the main bacterial group impacted by CSD in mice, reverts the higher sensitivity to inflammation in ex-germ-free mice colonized by CSD pups’ microbiota.ConclusionsEarly-life gut microbiota-host crosstalk alterations related to CSD could be the linchpin behind the phenotypic effects that lead to increased susceptibility to an induced inflammation later in life in mice.BBJL6KRzb7pAFtZtZ-zX7MVideo

Cerrado and Pantanal fruit flours affect gut microbiota composition in healthy and post-COVID-19 individuals: an invitro pilot fermentation study.

Cerrado and Pantanal plants can provide fruits with high nutritional value and antioxidants. This study aims to evaluate four fruit flours (from jatobá pulp, cumbaru almond, bocaiuva pulp and bocaiuva almond) and their effects on the gut microbiota in healthy (HD) and post-COVID-19 individuals (PC). An invitro batch system was carried out, the microbiota was analysed by 16S rRNA amplicon sequencing and the short-chain fatty acids ratio was determined. Furthermore, the effect of jatobá pulp flour oil (JAO) on cell viability, oxidative stress and DNA damage was investigated in a myelo-monocytic cell line. Beyond confirming a microbiota imbalance in PC, we identified flour-specific effects: (i) reduction of Veillonellaceae with jatobá extract in PC samples; (ii) decrease in Akkermansia with jatoba and cumbaru flours; (iii) decreasing trend of Faecalibacterium and Ruminococcus with all flours tested, with the exception of the bocaiuva almond in HD samples for Ruminococcus and (iv) increase in Lactobacillus and Bifidobacterium in PC samples with bocaiuva almond flour. JAO displayed antioxidant properties protecting cells from daunorubicin-induced cytotoxicity, oxidative stress and DNA damage. The promising microbiota-modulating abilities of some flours and the chemopreventive effects of JAO deserve to be further explored in human intervention studies.

Rumen microbial composition associated with the non‐glucogenic to glucogenic short‐chain fatty acids ratio in Holstein cows

This study aimed to determine the physiological features and rumen microbial composition associated with the non-glucogenic-to-glucogenic short-chain fatty acids ratio (NGR). Holstein cows were housed in a free-stall barn with an automatic milking system and fed a partially mixed ration. Physiological and microbial analyses were performed on 66 datasets collected from 66 cows (50-250 days in milk). NGR was positively correlated with ruminal pH, relative abundances of protozoa and fungi, methane conversion factor, methane intensity, plasma lipids, parity, and milk fat, and negatively correlated with total short-chain fatty acids. To highlight the differences in bacterial and archaeal compositions between NGRs, low-NGR cows (N = 22) were compared with medium-NGR (N = 22) and high-NGR (N = 22) cows. The low-NGR group was characterized by a lower abundance of Methanobrevibacter and a higher abundance of operational taxonomic units belonging to the lactate-producing, such as Intestinibaculum, Kandleria, and Dialister, and the succinate-producing Prevotella. Our findings indicate that NGR affects the methane conversion factor, methane intensity, and blood and milk compositions. Low NGR is associated with a higher abundance of lactate- and succinate-producing bacteria and lower abundances of protozoa, fungi, and Methanobrevibacter.

Effects of short-chain fatty acids on intestinal function in an enteroid model of hypoxia.

The healthy GI tract is physiologically hypoxic, but this may be perturbed by certain acute and chronic stressors that reduce oxygen availability systemically. Short-chain fatty acids have been shown to have beneficial effects on intestinal barrier function and inflammation. Therefore, our objective was to see whether short-chain fatty acids (SCFA) would improve GI barrier function, reduce production of pro-inflammatory cytokines, and increase the expression of genes regulating GI barrier function in enteroids exposed to hypoxia. Human duodenal enteroid monolayers were placed under hypoxia (1.0% O2) for 72h with either 24, or 48h pre-treatment with a high acetate ratio of SCFA's or high butyrate ratio or placed under hypoxia concurrently. Transepithelial electrical resistance (TEER) increased with SCFA pre-treatment, especially 48h of pre-treatment and this was maintained through the first 48h of hypoxia while cells saw barrier function dramatically decrease by 72h of hypoxia exposure. Inflammatory protein secretion largely decreased with exposure to hypoxia, regardless of SCFA pre-treatment. Gene expression of several genes related to barrier function were decreased with exposure to hypoxia, and with concurrent and 24h SCFA pre-treatment. However, 48h SCFA pre-treatment with a high butyrate ratio increased expression of several metabolic and differentiation related genes. Overall, pre-treatment or concurrent treatment with SCFA mixtures were not able to overcome the negative impacts of hypoxia on intestinal function and cells ultimately still cannot be sustained under hypoxia for 72h. However, 48h pre-treatment maintains TEER for up to 48h of hypoxia while upregulating several metabolic genes.

Process-based modelling of microbial community dynamics in the human colon

The human colon contains a dynamic microbial community whose composition has important implications for human health. In this work, we build a process-based model of the colonic microbial ecosystem and compare with general empirical observations and the results of in vivo experiments. Our model comprises a complex microbial ecosystem along with absorption of short chain fatty acids (SCFA) and water by the host through the gut wall, variations in incoming dietary substrates (in the form of ‘meals’ whose composition varies in time), bowel movements, feedback on microbial growth from changes in pH resulting from SCFA production and multiple compartments to represent the proximal, transverse and distal colon. We verify our model against a number of observed criteria, e.g. total SCFA concentrations, SCFA ratios, mass of bowel movements, pH and water absorption over the transit time; and then run simulations investigating the effect of colonic transit time, and the composition and amount of indigestible carbohydrate in the host diet, which we compare with in vivo studies. The code is available as an R package (microPopGut) to aid future research.

Association of Diet Quality Measured by Three A Priori-Defined Dietary Patterns With Gut Microbiota and Intestinal Permeability Among Obese Individuals

ObjectivesThe human gastrointestinal tract (GI) may play a critical role in the prevention of obesity and metabolic diseases. Considering the importance of a healthy diet for optimal health, this study examined associations of diet quality assessed by three a priori-defined dietary patterns (Healthy Eating Index 2010 [HEI-2010], Mediterranean Eating Pattern for Americans [MEPA], and Dietary Approaches to Stop Hypertension [DASH] with gut microbiota, short-chain fatty acids (SCFA) and intestinal permeability markers in adult obese participants. MethodsAnalyses utilized baseline data from 103 obese subjects (43.8 ± 11.3 years, body mass index ≥30 kg/m2, 72.8% females, 64.1% blacks) who participated in a probiotic/prebiotic supplement trial. Diet was assessed using a validated food frequency questionnaire. Associations of diet quality with outcome measures were assessed using partial correlation coefficient adjusting for relevant covariates. General linear models (GLM) were applied to compare covariate-adjusted means of outcomes for tertiles of respective dietary patterns scores. ResultsScores of HEI-2010 (r = 0.25, P = 0.02), MEPA (r = 0.24, P = 0.03) and DASH (r = 0.28, PP = 0.008) were positively associated with Blautia abundance. HEI-2010 score was positively associated butyrate and propionate to total SCFA ratio (r = 0.24, P = 0.048). Intestinal permeability marker, urinary 24-hr sucralose levels were inversely associated with HEI-2010 (r= –0.30, P = 0.009) and MEPA (r= –0.26, P = 0.02) score. The results were similar when GLM models were performed. No significant associations were observed between scores of dietary patterns and measures of microbial diversity. ConclusionsBlautia abundance and inversely associated with intestinal permeability markers such as urinary 24-h sucralose levels suggesting diet quality may have positive impact on the human GI community. Funding SourcesNo funding support.

A low glycemic index, energy-restricted diet but not Lactobacillus rhamnosus supplementation changes fecal short-chain fatty acid and serum lipid concentrations in women with overweight or obesity and polycystic ovary syndrome.

To evaluate if changes in fecal short-chain fatty acids (SCFA) content with an energy-restricted diet and with/without 12 × 109 CFU/day of Lactobacillus rhamnosus supplementation affect the abundance of selected gut bacteria and lipid profile in overweight and obese women with PCOS. This randomized controlled trial involved 40 overweight and obese women with a mean age of 28.8 ± 4.8 years diagnosed with PCOS. The subjects were randomly assigned to an energy-restricted diet group (D group; n = 21) or energy-restricted diet + Lactobacillus rhamnosus supplementation group (DP group; n=19). SCFA, selected gut bacteria (Akkermansia muciniphila, Bifidobacterium longum, and Faecalibacterium prausnitzii) abundance, lipid profile and anthropometric parameters were evaluated at baseline and after twenty weeks of intervention. The energy-restricted diet significantly reduced body weight, BMI, fat mass, acetic and butyric acids, and improved the lipid profile (total cholesterol, low-density lipoprotein cholesterol, and triglycerides) of both groups. Changes in the molar ratio of SCFA towards the correct ratio were also observed. All the results were independent of Lactobacillus rhamnosus supplementation, with no significant differences between the two groups. Twenty weeks of probiotic supplementation has no additional beneficial effects on selected gut bacteria abundance, SCFA levels, or lipid profile beyond the effect of an energy-restricted diet in overweight and obese women with PCOS.

Fecal Short-Chain Fatty Acid Ratios as Related to Gastrointestinal and Depressive Symptoms in Young Adults.

Short-chain fatty acids (SCFAs) are produced by the gut microbiota and may reflect health. Gut symptoms are common in individuals with depressive disorders, and recent data indicate relationships between gut microbiota and psychiatric health. We aimed to investigate potential associations between SCFAs and self-reported depressive and gut symptoms in young adults. Fecal samples from 164 individuals (125 were patients with psychiatric disorders: mean [standard deviation] age = 21.9 [2.6] years, 14% men; 39 nonpsychiatric controls: age = 28.5 [9.5] years, 38% men) were analyzed for the SCFA acetate, butyrate, and propionate by nuclear magnetic resonance spectroscopy. We then compared SCFA ratios with dimensional measures of self-reported depressive and gut symptoms. Depressive symptoms showed a positive association with acetate levels (ρ = 0.235, p = .003) and negative associations with both butyrate (ρ = -0.195, p = .014) and propionate levels (ρ = -0.201, p = .009) in relation to total SCFA levels. Furthermore, symptoms of diarrhea showed positive associations with acetate (ρ = 0.217, p = .010) and negative associations with propionate in relation to total SCFA levels (ρ = 0.229, p = 0-007). Cluster analysis revealed a heterogeneous pattern where shifts in SCFA ratios were observed in individuals with elevated levels of depressive symptoms, elevated levels of gut symptoms, or both. Shifts in SCFAs are associated with both depressive symptoms and gut symptoms in young adults and may have of relevance for treatment.

Neuroprotective effect of both synbiotics and ketogenic diet in a pentylenetetrazol-induced acute seizure murine model

ObjectiveWe aimed to maximize the efficacy of both ketogenic diet (KD) and other treatments to protect brain from acute seizure. MethodsL. fermentum MSK 408 strain, galactooligosaccharide (GOS), and L. fermentum MSK 408 with GOS were administered with two different diets for 8 weeks. To reveal the relationships among gut microbiota, fecal short-chain fatty acids (SCFAs) and brain related action against pentylenetetrazole (PTZ)-induced kindling, qPCR, NGS, and GC–MS analyses were used. ResultsKD administration significantly reduced PTZ-induced seizure through reducing cell damage in the specific part of the brain; this effect was not interrupted by co-administration of synbiotics. Additionally, the synbiotic-treated normal diet (ND) group showed reduced seizure-related scores. SCFA concentrations of both KDs and ND with synbiotics (NDS) were dramatically reduced compared to those with NDs. Interestingly, NDS group showed independently different SCFAs ratios compared to both ND and KD group, possibly related to a reduction in seizure symptoms compared with that by KD groups. The gut microbiota modulation by KD suggested that the gut microbiota aids the host in generating energy, thus increase the usage of SCFAs such as butyrate and acetate. SignificanceThe results suggest that KD could reduce PTZ-induced seizures through modulating various factors such as the neuroendocrine system, brain protection, gut microbiota, fecal SCFAs, and gene expression in the gut and brain. Additionally, synbiotic treatment with KD could be a better method to reduce the side effects of KD without interrupting its anti-seizure effect. However, ND with synbiotics seizure reducing effect requires further analysis.

Short chain fatty acids and monocarboxylate transporters in irritable bowel syndrome.

Gut microbiota ferments indigestible food that rests in the colon to produce short-chain fatty acids (SCFAs) acetate, propionate, and butyrate. Colonic SCFA stimulate the synthesis of serotonin which is central in irritable bowel syndrome (IBS) pathophysiology. Reduced SCFA have been linked to specific IBS symptoms like colonic hyperalgesia and hypersensitivity. SCFA enter the colonocyte mainly via 2 energy-dependent monocarboxylate transporters, MCT1 (SLC16A1) and SMCT1 (SLC5A8). We investigated specific gut microbiota, SCFA concentrations, and monocarboxylate transporter mRNA expression in patients with IBS. A total of 30 IBS patients-15 constipation-predominant (C-IBS) and 15 diarrhoea-predominant (D-IBS)-and 15 healthy controls were recruited. Bacteroidetes and Bifidobacterium species were analyzed using quantitative polymerase chain reaction (qPCR) on stool samples. SCFA concentrations were determined by gas chromatography/mass spectroscopy of stool samples. Monocarboxylate transporter mRNA was quantified by qPCR on colon biopsy specimens. Bacteroides was significantly increased in the D-IBS group compared with the C-IBS group and healthy controls. Bifidobacterium was significantly reduced in both IBS groups. SCFA ratios were altered in both IBS groups with a reduction of all 3 measured SCFA in C-IBS and acetic acid in D-IBS. MCT1 and SMCT1 were significantly reduced in C-IBS and D-IBS. In agreement with findings of previous studies, the microbiota assessed were significantly altered inferring dysbiosis in IBS. SCFA and their ratios were significantly altered in both IBS groups. SCFA transporters, MCT1 and SMCT1 were significantly reduced in both IBS groups, suggesting reduced colonocyte SCFA transfer. SCFA availability and transfer into the colonocytes may be important in IBS pathogenesis and should be prospectively studied.

Examination of hydrogen cross-feeders using a colonic microbiota model

BackgroundHydrogen cross-feeding microbes form a functionally important subset of the human colonic microbiota. The three major hydrogenotrophic functional groups of the colon: sulphate-reducing bacteria (SRB), methanogens and reductive acetogens, have been linked to wide ranging impacts on host physiology, health and wellbeing.ResultsAn existing mathematical model for microbial community growth and metabolism was combined with models for each of the three hydrogenotrophic functional groups. The model was further developed for application to the colonic environment via inclusion of responsive pH, host metabolite absorption and the inclusion of host mucins. Predictions of the model, using two existing metabolic parameter sets, were compared to experimental faecal culture datasets. Model accuracy varied between experiments and measured variables and was most successful in predicting the growth of high relative abundance functional groups, such as the Bacteroides, and short chain fatty acid (SCFA) production. Two versions of the colonic model were developed: one representing the colon with sequential compartments and one utilising a continuous spatial representation. When applied to the colonic environment, the model predicted pH dynamics within the ranges measured in vivo and SCFA ratios comparable to those in the literature. The continuous version of the model simulated relative abundances of microbial functional groups comparable to measured values, but predictions were sensitive to the metabolic parameter values used for each functional group. Sulphate availability was found to strongly influence hydrogenotroph activity in the continuous version of the model, correlating positively with SRB and sulphide concentration and negatively with methanogen concentration, but had no effect in the compartmentalised model version.ConclusionsAlthough the model predictions compared well to only some experimental measurements, the important features of the colon environment included make it a novel and useful contribution to modelling the colonic microbiota.

Evaluation of the Levels of Metabolites in Feces of Patients with Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD), which include ulcerative colitis (UC) and Crohn’s disease (CD), are chronic intestinal inflammatory disorders with only partially known etiology. They are characterized by chronic recurrent inflammation of the intestinal mucosa and lead to a significant decrease in the quality of life and death of patients. IBD is associated with suppression of normal intestinal microflora, particularly, a decrease in the number of bacteria—producers of short chain fatty acids (SCFAs) that exhibit anti-inflammatory and protective properties. Among various methods used for correction of intestinal microflora, fecal microbiota transplantation (FMT) attracts particular attention. FMT consists of the infusion of a fecal suspension from a healthy donor to the intestinal tract of a recipient patient. Such treatment is usually accompanied by a positive therapeutic effect with the restoration of the normal intestinal microflora of the recipient patient. A significant drawback of this method is the lack of standardization. Evaluation of metabolites produced by intestinal microflora, particularly, SCFAs, may be used for objective assessment of the functional state of the intestinal microbiota and, consequently, the success of the FMT procedure. Using gas chromatography and nuclear magnetic resonance spectroscopy, we have analyzed the concentrations and molar ratios of SCFAs from feces of 60 healthy donors. The results obtained by these two methods were in good accord with each other and with the published data. The analysis of SCFAs in the feces of patients with UC (19 patients) and CD (17 patients) revealed a general decrease in the concentration of SCFAs in the studied groups as compared with controls and significant fluctuations in the values of the studied group. Using limited sets of IBD patients (6 patients with UC and 5 patients with CD) we determined concentrations of SCFAs before and within 30 days of observation after FMT. In the selected time period, FMT exerts an effect on the SCFAs levels. Despite the fact that within 30 days of observation the SCFAs profiles, specifically attributed to healthy donors, have not been fully restored, the tendency to their achievement was clearly observed in both sets of UC and CD patients.

Impact of time and temperature on gut microbiota and SCFA composition in stool samples.

Gut dysbiosis has been implicated in the pathophysiology of a growing number of non-communicable diseases. High through-put sequencing technologies and short chain fatty acid (SCFA) profiling enables surveying of the composition and function of the gut microbiota and provide key insights into host-microbiome interactions. However, a methodological problem with analyzing stool samples is that samples are treated and stored differently prior to submission for analysis potentially influencing the composition of the microbiota and its metabolites. In the present study, we simulated the sample acquisition of a large-scale study, in which stool samples were stored for up to two days in the fridge or at room temperature before being handed over to the hospital. To assess the influence of time and temperature on the microbial community and on SCFA composition in a controlled experimental setting, the stool samples of 10 individuals were exposed to room and fridge temperatures for 24 and 48 hours, respectively, and analyzed using 16S rRNA gene amplicon sequencing, qPCR and nuclear magnetic resonance spectroscopy. To best of our knowledge, this is the first study to investigate the influence of storage time and temperature on the absolute abundance of methanogens, and of Lactobacillus reuteri. The results indicate that values obtained for methanogens, L. reuteri and total bacteria are still representative even after storage for up to 48 hours at RT (20°C) or 4°C. The overall microbial composition and structure appeared to be influenced more by laboratory errors introduced during sample processing than by the actual effects of temperature and time. Although microbial activity was demonstrated by elevated SCFA at both 4°C and RT, SCFAs ratios were more stable over the different conditions and may be considered as long as samples are come from similar storage conditions.

Relation Between Total Polyphenol Intake and Markers of Intestinal Health in Obese Humans

Abstract Objectives Polyphenol intake has been associated with improved health outcomes, but the relation between polyphenol intake, gastrointestinal health, and systemic health outcomes is not fully known. Many polyphenols become bioavailable once transformed into metabolites by the gut microbial community. Thus, it is reasonable to assume that the intimate interaction between polyphenols and microbiota may influence both gastrointestinal and systemic health. The objective of the current study was to assess the relation of daily polyphenol intake with intestinal permeability, microbiota profile, and fecal short-chain fatty acids in a sample of obese humans. Methods The analyses were conducted among 92 adult obese participants (body mass index ≥ 30 kg/m2). Polyphenol intake was calculated from a food frequency questionnaire (VioscreenTM) using Polyphenol-Explorer and published literature. Intestinal permeability was measured through collection of 24-hour urine after consumption of a sugar mixture and presented as sucralose and sucralose: lactulose excretion as a % of the oral dose. Microbiota profile and short-chain fatty acids (SCFA) were assessed using 16S sequencing and gas chromatography, respectively. Associations of polyphenol intake between intestinal health markers were examined by correlational analyses; all analyses were conducted using SPSS (version 26). Results Mean age of participants was 44.1 ± 11.3 years; 70.7% were females and 63.0% self-identified as Black/African American. Daily polyphenol intake was 2,733 ± 2,129 mg/day. Primary food group contributors to polyphenol intake were drinks (coffee/tea; 33.2%), fruit (23.9%) and vegetarian protein sources (nuts/seeds/legumes; 15.6%). Total polyphenol intake was positively correlated with fecal butyrate (µg/g) (rho = 0.255; p = 0.029) and butyrate: SCFA ratio (rho = 0.274, p = 0.018). However, polyphenol intake was not correlated to microbiota taxa or markers of intestinal permeability (P > 0.05). Conclusions Dietary intake of polyphenols are associated with fecal SCFA concentrations, but further investigation through intervention studies is needed to elucidate the potential relation between polyphenols and markers of gastrointestinal health. Funding Sources Supported by the Agriculture and Food Research Initiative from the USDA National Institute of Food and Agriculture.

Evaluation of metabolites levels in feces of patients with inflammatory bowel diseases

Inflammatory bowel diseases (IBD), which include ulcerative colitis (UC) and Crohn's disease (CD), are chronic intestinal inflammatory disorders with an unknown etiology. They are characterized by chronic recurrent inflammation of the intestinal mucosa and lead to a significant decrease in the quality of life and death of patients. IBD are associated with suppression of normal intestinal microflora, including a decrease in bacteria, producers of short chain fatty acids (SCFAs), exhibiting anti-inflammatory and protective properties. Among the various methods of intestinal microflora correction, fecal microbiota transplantation (FMT), which engrafts the fecal microbiota from a healthy donor into a patient recipient, is of a particular interest. As a result, a positive therapeutic effect is observed, accompanied by the restoration of the normal intestinal microflora of the patient. A significant drawback of the method is the lack of standardization. Metabolites produced by intestinal microflora, namely SCFAs, allow objective assessment of the functional state of the intestinal microbiota and, consequently, the success of the FMT procedure. Using gas chromatography and nuclear magnetic resonance spectroscopy techniques, we have analyzed concentrations and molar ratios of SCFAs in fecal samples of 60 healthy donors. Results were in good accord when comparing two methods as well as with published data. Analysis of SCFAs in feces of patients with UC (19 patients) and CD (17 patients) revealed a general decrease in the concentration of fatty acids in the experimental groups with significant fluctuations in the values in experimental groups compared to control group of healthy donors. On the limited group of IBD patients (6 patients with UC and 5 patients with CD) concentration of SCFAs before and within 30 days of observation after FMT was determined. It was shown that FMT had a significant impact on the SCFAs levels within 1 month term; tendency to reach characteristics of healthy donors is unambiguously traced for both diseases.

Effects of <i>γ</i>-Polyglutamic Acid on Blood Glucose and Caecal Short Chain Fatty Acids in Adult Male Mice

γ-Polyglutamic acid (γ-PGA) is a major component of Natto. We hypothesized that γ-PGA could reduce postprandial glucose rise and plasma glucose levels. Mice were fed a 0.1% γ-PGA—containing diet or control diet for 91 days. Maltose and starch tolerance tests were performed, and plasma lipids, glucose levels, and caecal short chain fatty acids (SCFAs) were measured. Mice were co-administered γ-PGA and starch to suppress the initial rise in blood glucose levels. Blood glucose levels at 15 min were significantly lower in the PGA group than in the Con group (P 0.05). The plasma glucose level and NEFA level were also significantly lower in the PGA group (P 0.05), and caecal acetic acid/total caecal SCFAs ratio was significantly increased in the PGA group (P 0.05). Significant negative correlations existed between the caecal acetic acid/propionic acid ratio and the weight of visceral fat/BW (r = -0.57, P = 0.0318). Our results suggest that γ-PGA may effectively prevent metabolic syndrome by lowering blood glucose levels.

Effect of complete feed block with tree leaves rich in hydrolysable and condensed tannins on nutrient utilization, rumen fermentation and growth performance of lambs.

Thirty lambs (Avishaan genotype, 10weeks old, 14.0±0.2kg live weight) were randomly assigned into three equal treatment groups to study the effect of complete feed blocks (CFB; concentrate and roughage at 70:30 ratio) with three different tanniniferous tree leaves on intake and utilization of nutrients, rumen fermentation, microbial protein synthesis and growth performance. The treatments were T1 (Control), CFB1 with Vigna sinensis hay; T2, CFB2 with Acacia nilotica leaves rich in hydrolysable tannins (HT); and T3, CFB3 with Ziziphus nummularia leaves rich in condensed tannins (CT). The three CFBs were fed ad libitum to the respective groups of lambs for a period of 12weeks. There was lower (p<.05) intake of dry matter (DM), total carbohydrates (TCHO) and fibre components in T2 compared with T1 and T3. However, the digestibility of nutrients except crude protein (CP) was higher in T2. Diet had no effect (p>.05) on the LW gain in lambs. Amongst the three groups, T3 showed enhanced N utilization with a comparable microbial protein synthesis, the lowest being in T2. The T2 group of lambs had higher propionate and lower non-glucogenic: glucogenic short-chain fatty acids ratio. It may be concluded that tanniniferous tree leaves at 30% of total mixed ration can meet the requirement of nutrients for desired post-weaning growth.

Inflammatory bowel disease is associated with increased gut-to-blood penetration of short-chain fatty acids: A new, non-invasive marker of a functional intestinal lesion.

What is the central question of this study? 'Leaky gut' has been found in intestinal and extra-intestinal diseases. However, functional evaluation of intestinal permeability is not widely used as a diagnostic marker, possibly owing to significant limitations of currently used permeability assays. There is an unmet need for development of a new, non-invasive test to assess intestinal function. What is the main finding and its importance? We show that an increased blood-to-stool ratio of the concentration of gut bacteria-produced short-chain fatty acids may be used as a marker of gut permeability. Our findings lay the groundwork for establishing a new, non-invasive, risk-free diagnostic tool in diseases associated with intestinal barrier malfunction, such as inflammatory bowel disease. Intestinal diseases, such as inflammatory bowel disease (IBD), are characterized by an impaired gut-blood barrier commonly referred to as 'leaky gut'. Therefore, functional evaluation of the gut-blood barrier is a promising diagnostic marker. We hypothesized that short-chain fatty acids (SCFAs) produced by gut bacteria might serve as a marker in IBD. Animal experiments were performed on male Sprague-Dawley rats with acetic acid-induced colitis and in sham control animals. The gut-blood barrier permeability was determined by assessing the ratios of the following: (i) portal blood concentration of SCFAs (Cp ) to faecal concentration of SCFAs (Cf ); (ii) systemic blood concentration of SCFAs (Cs ) to faecal concentration of SCFAs (Cf ); and (iii) Cp and Cs of fluorescein isothiocyanate (FITC)-dextran administered into the colon. As a clinical study, we evaluated Cs , Cf and the Cs /Cf ratio of SCFAs in six paediatric patients with IBD, assessed as mild/moderate/severe by the Paediatric Ulcerative Colitis Activity Index (PUCAI) and the Paediatric Crohn's Disease Activity Index (PCDAI) at the time of sample collection, and nine age-matched healthy control subjects. Rats with histologically confirmed IBD had significantly increased ratios of Cp /Cf and Cs /Cf for SCFAs. This was positively correlated with the plasma FITC-dextran concentration. Likewise, IBD patients showed a significantly higher Cs /Cf ratio for SCFAs, including acetic, valeric, isocaproic, caproic and propionic acids, in comparison to control subjects. In conclusion, in the rats and in paediatric patients with IBD we found an increased blood-to-stool ratio of SCFAs, suggesting an increased gut-to-blood penetration of SCFAs. These findings pave the way for a new, non-invasive diagnostic tool in IBD and other diseases accompanied by intestinal barrier malfunction.

Markers of dysbiosis in patients with ulcerative colitis and Crohn's disease.

The aim of the study was to study the taxonomic and functional composition of the gut microbiota in ulcerative colitis (UC) and Crohn's disease (CD) patients to identify key markers of dysbiosis in IBD. Fecal samples obtained from 95 IBD patients (78 UC and 17 CD) as well as 96 healthy volunteers were used for whole-genome sequencing carried out on the SOLiD 5500 W platform. Taxonomic profiling was performed by aligning the reeds, not maped on hg19, on MetaPhlAn2 reference database. Reeds were mapped using the HUNAnN2 algorithm to the ChocoPhlAn database to assess the representation of microbial metabolic pathways. Short-chain fatty acids (SCFA) level were measured in fecal samples by gas-liquid chromatographic analysis. Changes in IBD patients gut microbiota were characterized by an increase in the representation of Proteobacteria and Bacteroidetes phyla bacteria and decrease in the number of Firmicutes phylum bacteria and Euryarchaeota phylum archaea; a decrease in the alpha-diversity index, relative representation of butyrate-producing, hydrogen-utilizing bacteria, and Methanobrevibacter smithii; increase in the relative representation of Ruminococcus gnavus in UC and CD patients and Akkermansia muciniphila in CD patients. Reduction of Butyryl-CoA: acetate CoA transferase gene relative representation in CD patients, decrease of absolute content of SCFA total number as well as particular SCFAs and main SCFAs ratio in IBD patients may indicate inhibition of functional activity and number of anaerobic microflora and/or an change in SCFA utilization by colonocytes. the revealed changes can be considered as typical signs of dysbiosis in IBD patients and can be used as potential targets for IBD patients personalized treatment development.

DETERMINATION OF SHORT CHAIN FATTY ACIDS IN RAT FECES TREATED WITH RESISTANT STARCH BY HPLC

Background: Short-chain fatty acids (SCFAs), mostly found in colon feces, is an important group of gut microbial metabolites from anaerobic fermentation of indigestible carbohydrates. Objectives: To develope an HPLC method to determined SCFAs in rat feces treated with resistant starch. Materials and methods: Sample is the rat feces fed with acetate wheat starch and normal starch; fatty acid hydrazides are derived from SCFAs in feces and measured by HPLC. After validated as guidance of US-FDA, method is applied to identify SCFAs in rat treated two types of starch. Results: the HPLC condition was optimized as follow: Eclipse XDB–C8 (4.6mmx150mm, 5µm) column; mobile phase: methanol, acetonitrile and 0,057 mM acid triflouroacetic (pH 4.5) (0:13:87 – 10:20:70 – 0:13:87, v/v/v) in 40 mins;, examinized wavelength: 396 nm. Method was validated with parameters: system suitability, specificity, linearity, precision, accuracy and stability. The result showed amount ratio of SCFAs in feces of mice group treated with acetate wheat starch containing resistant starch higher than from the diet containing normal starch significantly. Conclusion: This method can be used to investigate SCFAs in the gastrointestinal segments of the living organism. Key words: SCFAs, HPLC, resistant starch, feces