Short-chain Fatty Acid Profiles Research Articles

Donepezil ameliorates gut barrier disruption in doxorubicin-treated rats

An impact of donepezil against doxorubicin-induced gut barrier disruption and gut dysbiosis has never been investigated. Twenty-four male Wistar rats were divided into three groups. Each group was treated with either vehicle as a control, doxorubicin, or doxorubicin-cotreated with donepezil. Heart rate variability was assessed to reflect the impact of doxorubicin and donepezil. Then, animals were euthanized, and the ileum and its contents were collected in each case to investigate the gut barrier and gut microbiota, respectively. The microbiota-derived endotoxin, trimethylamine N-oxide (TMAO), and short-chain fatty acids (SCFAs) in the serum were determined. An increase in the sympathetic tone, endotoxins, and TMAO levels with disruption of the gut barrier and a decrease in SCFAs levels were observed in doxorubicin-treated rats. Gut microbiota of doxorubicin-treated rats was significantly different from that of the control group. Donepezil treatment significantly decreased the sympathetic tone, restored the gut barrier, and reduced endotoxin and TMAO levels in doxorubicin-treated rats. Nonetheless, donepezil administration did not alter the gut microbiota profile and levels of SCFAs in doxorubicin-treated rats. Doxorubicin impaired the autonomic balance and the gut barrier, and induced gut dysbiosis, resulting in gut toxicity. Donepezil partially improved the doxorubicin-induced gut toxicity through balancing the autonomic disturbance.

233 Inclusion of a multispecies fungal feed additive in forage-based diets fed to beef cattle: Effects on growth performance and ruminal fermentation

Abstract The objective was to evaluate the effect of adding a multispecies fungal feed additive (MFA; Aspergillus flavus, Aspergillus niger, Aspergillus oryzae) to forage-based diets fed to beef cattle on growth performance and ruminal fermentation. Experiment 1 evaluated the effect of supplementing Angus × SimAngus-crossbred steers [n = 80; initial body weight (BW) = 370 ± 44 kg] with varying doses of an MFA in a randomized complete block design. Steers were blocked by BW and housed in 8 feedlot pens (randomly assigned 2 pens per treatment) where a hay-based diet was fed for 122 d. The hay-based diet was offered with the inclusion of the MFA at 0.02, 0.04, and 0.08 % of the diet dry matter (DM), or without the inclusion of the MFA (CON). Steers were weighed at 28-d intervals. For experiment 2, ruminally cannulated Angus × SimAngus cows (n = 4; initial BW = 569 ± 21 kg) were used in a crossover design with two 21-d study periods to evaluate the effect of dietary inclusion of an MFA on in situ digestion and rumen metabolites. Treatments consisted of a forage-based diet with (WFA) or without (CON) the inclusion of the MFA. In situ digestion was evaluated on d 5, 10, and 20 throughout each period. In-situ bags were incubated in the rumen for 0 to 36 h, sampling every 4 h. On d 20, samples of ruminal fluid were collected to analyze short-chain fatty acids (SCFA) concentration. All data were analyzed using the PROC MIXED procedure of SAS. For experiment 1, a polynomial contrast was used. For experiment 2, the interaction between period and treatment was not significant (P > 0.45). In Experiment 1, the final BW, average daily gain (ADG), and gain to feed ratio (G:F) changed cubically (P ≤ 0.04; Table 1) as dietary inclusion of the MFA increased. Steers supplemented with the MFA at a rate of 0.02% of the diet DM were heavier at the end of the 122-d study period and had the greatest ADG and G:F among treatments. No differences between treatments (P ≥ 0.37) were observed for dry matter intake. In Experiment 2, no treatment × time interactions and treatment effects were detected (P ≥ 0.17; Table 2) for the in-situ disappearance rate and degradation kinetics of the diet DM, neutral detergent fiber, and acid detergent fiber. In addition, MFA supplementation did not affect (P ≥ 0.13; Table 3) the SCFA profile and the total SCFA content in the rumen fluid. Results from these studies indicate that dietary inclusion of an MFA might be an effective alternative to increase the feed efficiency of beef cattle-fed forage-based diets. However, the precise mode of action warrants further investigations.

168 Effects of feeding barley-based diets differing in fermentable starch and fiber on nutrient digestion and body composition in weaned pigs

Abstract Hulled and hull-less barley grains containing low insoluble fiber are alternative energy sources in weaning diets but are typically not part of weaned pig diets. The range in fermentable starch and fiber content among barley cultivars presents opportunities to investigate whether these fermentable carbohydrates of barley grain do influence nutrient digestion, gut short chain fatty acid (SCFA) profile and body composition. To explore, pigs [n = 40; body weight (BW) = 8.6 kg; 1-wk post-weaning] were housed individually and fed 1 of 4 diets containing 600 to 705 g of cereal grain/kg: 1) low-fermentable wheat (LFW); 2) high β-glucan, hull-less barley (HFBB); 3) high amylose, hull-less barley (HFAB); or 4) low-fermentable hulled barley (LFB). Diets provided 10.2 and 9.8 MJ NE/kg, and 1.32 and 1.21 g standardized ileal digestible (SID) lysine/MJ NE for phase 1 (d 0–14) and phase 2 (d 15–28), respectively. At the end of the trial, feces were collected, and pigs were slaughtered to collect digesta and the carcass that was subsequently ground. Subsamples of feces, digesta, and carcasses were freeze-dried and analyzed. The apparent ileal digestibility (AID) of crude protein (CP) and gross energy (GE) did not differ among diets. The AID of β-glucan was 3 times greater (P < 0.05) for LFW than HFBB and HFAB, while AID of starch was 12% less (P < 0.05) for HFAB than the other diets. Apparent total tract digestibility (ATTD) of GE and CP was 4.2 and 8.9% less (P < 0.05), respectively, for the 3 barley diets than the wheat diet. The apparent hindgut fermentation (AHF) of β-glucan was 2.6 times greater (P < 0.05) for HFAB and HFBB than LFW, while AHF of starch was 7.5 times greater for HFAB than LFW. The calculated NE value was greatest (P < 0.05) for LFW, intermediate for HFBB and HFAB, and least for LFB. Among diets, HFAB increased (P < 0.05) the concentration of butyrate (indicator of gut health) and propionate in cecal and colonic digesta, with butyrate up to 50% more (P < 0.05) than that of LFW. Carcass protein and lipid concentration did not differ among pigs fed the 4 diets. In conclusion, feeding barley instead of wheat grain to weaned pigs reduced diet nutrient digestibility but did not affect carcass protein and lipid concentration. Feeding high amylose barley increased gut SCFA concentration. Barley grain with increasing fermentable carbohydrates can thus be included as alternative ingredient in diets of young pigs.

Expression and clinical significance of short-chain fatty acids in patients with intrahepatic cholestasis of pregnancy.

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver condition that typically arises in the middle and late stages of pregnancy. Short-chain fatty acids (SCFAs), prominent metabolites of the gut microbiota, have significant connections with various pregnancy complications, and some SCFAs hold potential for treating such complications. However, the metabolic profile of SCFAs in patients with ICP remains unclear. To investigate the metabolic profiles and differences in SCFAs present in the maternal and cord blood of patients with ICP and determine the clinical significance of these findings. Maternal serum and cord blood samples were collected from both patients with ICP (ICP group) and normal pregnant women (NP group). Targeted metabolomics was used to assess the SCFA levels in these samples. Significant differences in maternal SCFAs were observed between the ICP and NP groups. Most SCFAs exhibited a consistent declining trend in cord blood samples from the ICP group, mirroring the pattern seen in maternal serum. Correlation analysis revealed a positive correlation between maternal serum SCFAs and cord blood SCFAs [r (Pearson) = 0.88, P = 7.93e-95]. In both maternal serum and cord blood, acetic and caproic acids were identified as key metabolites contributing to the differences in SCFAs between the two groups (variable importance for the projection > 1). Receiver operating characteristic analysis demonstrated that multiple SCFAs in maternal blood have excellent diagnostic capabilities for ICP, with caproic acid exhibiting the highest diagnostic efficacy (area under the curve = 0.97). Compared with the NP group, significant alterations were observed in the SCFAs of maternal serum and cord blood in the ICP group, although they displayed distinct patterns of change. Furthermore, the SCFA levels in maternal serum and cord blood were significantly positively correlated. Notably, certain maternal serum SCFAs, specifically caproic and acetic acids, demonstrated excellent diagnostic efficiency for ICP.

Integrated microbiomic and metabolomics insight into the ameliorating mechanisms of dietary Polygonatum cyrtonema saponin on ulcerative colitis

The occurrence and evolution of colitis can cause prejudicial damage to the intestinal barrier, with studies reporting positive effects of saponins on intestinal inflammation. Nevertheless, there is a lack of evidence regarding whether Polygonatum cyrtonema Saponin (PCS) can be employed as a food supplement ingredient to restore the intestinal barrier caused by dextran sodium sulfate (DSS). Here, the potential repair mechanisms of PCS on the intestinal barrier were intensively investigated via 16 S rRNA sequencing and non-targeted metabolomics techniques. The results showed that PCS intake effectively alleviated symptoms such as weight loss and colonic injury in DSS mice, reduced excessive inflammation, and restored intestinal barrier integrities via diminishing intestinal permeability and enhancing tight junction protein expression. Moreover, 16 S rRNA sequence analysis demonstrated that PCS could ameliorate the DSS-disrupted gut microbiota imbalances, especially restoring the abundance of Lactobacillus. Simultaneously, the favorable regulation of the gut microbiota was further bolstered from the improved short-chain fatty acids (SCFAs) profile, with a remarkable improvement in the contents of SCFAs by PCS. In addition, alterations in metabolites caused by the PCS intervention correlated significantly with the gut microbiota and PCS intervention subsequently modulated inflammation-associated metabolic pathways, in terms of amino acid metabolisms, ascorbate and aldarate metabolisms, and pyrimidine metabolisms. Collectively, our findings demonstrated that PCS can effectively mitigate intestinal inflammation, which may offer important perspectives for the preventions and treatments of intestinal disorders.

Short term supplementation with cranberry extract modulates gut microbiota in human and displays a bifidogenic effect

Cranberry is associated with multiple health benefits, which are mostly attributed to its high content of (poly)phenols, particularly flavan-3-ols. However, clinical trials attempting to demonstrate these positive effects have yielded heterogeneous results, partly due to the high inter-individual variability associated with gut microbiota interaction with these molecules. In fact, several studies have demonstrated the ability of these molecules to modulate the gut microbiota in animal and in vitro models, but there is a scarcity of information in human subjects. In addition, it has been recently reported that cranberry also contains high concentrations of oligosaccharides, which could contribute to its bioactivity. Hence, the aim of this study was to fully characterize the (poly)phenolic and oligosaccharidic contents of a commercially available cranberry extract and evaluate its capacity to positively modulate the gut microbiota of 28 human subjects. After only four days, the (poly)phenols and oligosaccharides-rich cranberry extract, induced a strong bifidogenic effect, along with an increase in the abundance of several butyrate-producing bacteria, such as Clostridium and Anaerobutyricum. Plasmatic and fecal short-chain fatty acids profiles were also altered by the cranberry extract with a decrease in acetate ratio and an increase in butyrate ratio. Finally, to characterize the inter-individual variability, we stratified the participants according to the alterations observed in the fecal microbiota following supplementation. Interestingly, individuals having a microbiota characterized by the presence of Prevotella benefited from an increase in Faecalibacterium with the cranberry extract supplementation.

Alterations of circulating free fatty acids in patients with pemphigus vulgaris.

Free fatty acids (FFA) have gained research interest owing to their functions in both local and systemic immune regulation. Changes in the serum levels of anti-inflammatory short chain fatty acids (SCFA), primarily derived from the gut microbiota, and pro-inflammatory medium (MCFA) and long (LCFA) chain fatty acids, derived from either the gut microbiota or the diet, have been associated with autoimmunity. Circulating FFA were retrospectively analysed by a gas chromatography-mass spectrometry method in the serum of 18 patients with pemphigus vulgaris (PV) at the baseline and 6 months (n = 10) after immunosuppressive treatments, and 18 healthy controls (HC). Circulating FFA were correlated with the Pemphigus Disease Area Index (PDAI) and serum concentrations of interferon-gamma (IFN-γ), Interleukin (IL)-17A, IL-5, IL-10 and IL-21. Principal Component analysis computed on FFA abundances revealed significant differences in the profile of SCFA (p = 0,012), MCFA (p = 0.00015) and LCFA (p = 0,035) between PV patients and HC, which were not significantly changed by immunosuppressive treatments. PV patients showed a significantly lower serum concentration of propionic (p < 0.0005) and butyric (p < 0.0005) acids, SCFA with anti-inflammatory functions, while hexanoic (p < 0.0005) and hexadecanoic (p = 0.0006) acids, pro-inflammatory MCFA and LCFA respectively, were over-represented. Treatments induced a significant decrease of hexanoic (p = 0.035) and a further increase of hexadecanoic (p = 0.046) acids. Positive correlations emerged between IFN-γ and acetic acid (Rho = 0.60), IFN-γ and hexanoic acid (Rho = 0.46), IL-5 and both hexadecanoic acid (Rho = 0.50) and octadecanoic acid (Rho = 0.53), butyric acid and PDAI (Rho = 0.53). PV was associated with a remarked imbalance of circulating FFA compared to HC. The serum alterations of SCFA, MCFA, and LCFA may contribute to promoting inflammation in PV. Deeper insights into the immunomodulatory functions of these molecules may pave the way for personalized dietary interventions in PV patients.

Maternal prebiotic supplementation during pregnancy and lactation modifies the microbiome and short chain fatty acid profile of both mother and infant

Background & AimsImproving maternal gut health in pregnancy and lactation is a potential strategy to improve immune and metabolic health in offspring and curtail the rising rates of inflammatory diseases linked to alterations in gut microbiota. Here, we investigate the effects of a maternal prebiotic supplement (galacto-oligosaccharides and fructo-oligosaccharides), ingested daily from <21 weeks’ gestation to six months’ post-partum, in a double-blinded, randomised placebo-controlled trial. MethodsStool samples were collected at multiple timepoints from 74 mother-infant pairs as part of a larger, double-blinded, randomised controlled allergy intervention trial. The participants were randomised to one of two groups; with one group recieving 14.2 g per day of prebiotic powder (galacto-oligosaccharides GOS and fructo-oligosaccharides FOS in ratio 9:1), and the other receiving a placebo powder consisting of 8.7 g per day of maltodextrin. The faecal microbiota of both mother and infants were assessed based on the analysis of bacterial 16S rRNA gene (V4 region) sequences, and short chain fatty acid (SCFA) concentrations in stool. ResultsSignificant differences in the maternal microbiota profiles between baseline and either 28-weeks’ or 36-weeks’ gestation were found in the prebiotic supplemented women. Infant microbial beta-diversity also significantly differed between prebiotic and placebo groups at 12-months of age. Supplementation was associated with increased abundance of commensal Bifidobacteria in the maternal microbiota, and a reduction in the abundance of Negativicutes in both maternal and infant microbiota. There were also changes in SCFA concentrations with maternal prebiotics supplementation, including significant differences in acetic acid concentration between intervention and control groups from 20 to 28-weeks’ gestation. ConclusionMaternal prebiotic supplementation of 14.2 g per day GOS/FOS was found to favourably modify both the maternal and the developing infant gut microbiome. These results build on our understanding of the importance of maternal diet during pregnancy, and indicate that it is possible to intervene and modify the development of the infant microbiome by dietary modulation of the maternal gut microbiome.

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

Development of the CE-C4D method for determination of organic acids in infants faeces using an in-house built instrument

Short-chain fatty acids (SCFAs) are a major group of products produced during colonic bacterial fermentation of nondigestible carbohydrates demonstrating several important functions, e.g. regulating the immune system activity or the lipid metabolism. A detailed profile and concentration characterization of SCFAs in infant faeces is essential for expanding knowledge regarding the role of SCFAs in infant physiology and pathophysiology. This research presents the development and validation of a capillary electrophoresis method with a contactless capacitively coupled conductivity detector (CE-C4D) for the analysis of SCFAs and succinic and lactic acids in infant faeces. The study focused on optimizing the background electrolyte, mainly dynamic capillary coating with polybrene, and utilizing cyclodextrins to achieve efficient separation. Validation parameters, such as linearity (0.993 – 0.998), limits of detection and quantification (LOD: 0.10 – 0.89 μg/mL; LOQ: 0.35 – 2.97 μg/mL), intra- and inter-day precision (1.71 – 5.69 % and 1.11 – 12.5 %, respectively), injection repeatability (0.91 – 5.70 %), trueness (-12.8 – 3.80 %), and matrix effect (78.8 – 108.6 %), were assessed and the method was found suitable for the purpose. The demonstrated method was successfully applied to determine nine organic acids in faecal samples.

Supplemented Infant Formula and Human Breast Milk Show Similar Patterns in Modulating Infant Microbiota Composition and Function In Vitro.

The gut microbiota of healthy breastfed infants is often dominated by bifidobacteria. In an effort to mimic the microbiota of breastfed infants, modern formulas are fortified with bioactive and bifidogenic ingredients. These ingredients promote the optimal health and development of infants as well as the development of the infant microbiota. Here, we used INFOGEST and an in vitro batch fermentation model to investigate the gut health-promoting effects of a commercial infant formula supplemented with a blend containing docosahexaenoic acid (DHA) (20 mg/100 kcal), polydextrose and galactooligosaccharides (PDX/GOS) (4 g/L, 1:1 ratio), milk fat globule membrane (MFGM) (5 g/L), lactoferrin (0.6 g/L), and Bifidobacterium animalis subsp. lactis, BB-12 (BB-12) (106 CFU/g). Using fecal inoculates from three healthy infants, we assessed microbiota changes, the bifidogenic effect, and the short-chain fatty acid (SCFA) production of the supplemented test formula and compared those with data obtained from an unsupplemented base formula and from the breast milk control. Our results show that even after INFOGEST digestion of the formula, the supplemented formula can still maintain its bioactivity and modulate infants' microbiota composition, promote faster bifidobacterial growth, and stimulate production of SCFAs. Thus, it may be concluded that the test formula containing a bioactive blend promotes infant gut microbiota and SCFA profile to something similar, but not identical to those of breastfed infants.

P175 HucMSC-Exo ameliorate experimental colitis via modulating gut microbiota and metabolites

Abstract Background Gut microbiota and metabolites have been shown to influence the development of inflammatory bowel disease (IBD). Exosomes derived from human umbilical cord mesenchymal stem cells (HucMSC-Exo) have been identified as a promising biological therapy for the treatment of IBD. Previous studies have described that HucMSC-Exo could modulate gut microbiota. However, the mechanism remains unclear. Here, we explored the role of gut microbiota and metabolites in HucMSC-Exo-mediated amelioration of experimental colitis. Methods Dextran sulfate sodium (DSS) was used to induce colitis. The role of HucMSC-Exo were assessed in colitis mice. Fecal microbiota transplantation (FMT) and sterile fecal filtrate gavage were employed to evaluate the effect of gut microbiota and metabolites. Gut microbiota and metabolites were analyzed through 16S rRNA sequencing and metabolomic profiling. The proportion of CD4+ T cells were phenotyped by multicolour flow cytometry. Results HucMSC-Exo treatment alleviated colon inflammation by regulating flora composition, significantly up-regulated the levels of bacteria such as Bacteroides, Parabacteroides distasonis, and Tannerellaceae. Meanwhile, HucMSC-Exo transformed metabolite short-chain fatty acid (SCFA) profiles, particularly increased butyrate level. Additionally, HucMSC-Exo selectively up-regulated the frequencies of regulatory T (Treg) cells as well as down-regulated the ratio of T helper type 17 (Th17) cells in colonic lamina propria to maintain intestinal immune homeostasis and repaired the colonic mucus barrier. FMT and sterile fecal filtrate gavage were conducted to confirm the above mechanism. Microbiota from HucMSC-Exo-treated mice alleviated the colitis over microbiota from DSS-treated mice. Sterile fecal filtrate from HucMSC-Exo-treated mice and butyrate induced similar beneficial outcomes, such as improved the Th17/Treg balance and repaired the colonic mucus barrier. Collectively, HucMSC-Exo ameliorate colitis by directly modulating gut microbiota and metabolites. Conclusion HucMSC-Exo ameliorated experimental colitis via directly modulating gut microbiota and metabolite butyrate, which could regulate CD4+T cells homeostasis and repair colonic mucus barrier. The findings demonstrated the HucMSC-Exo as a potential gut microbiota and metabolites modulator to treat IBD.

An Analysis of the Gut Microbiota and Related Metabolites following PCSK9 Inhibition in Statin-Treated Patients with Elevated Levels of Lipoprotein(a).

Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of global mortality, often associated with high blood levels of LDL cholesterol (LDL-c). Medications like statins and PCSK9 inhibitors, are used to manage LDL-c levels and reduce ASCVD risk. Recent findings connect the gut microbiota and its metabolites to ASCVD development. We showed that statins modulate the gut microbiota including the production of microbial metabolites involved in the regulation of cholesterol metabolism such as short chain fatty acids (SCFAs) and bile acids (BAs). Whether this pleiotropic effect of statins is associated with their antimicrobial properties or it is secondary to the modulation of cholesterol metabolism in the host is unknown. In this observational study, we evaluated whether alirocumab, a PCSK9 inhibitor administered subcutaneously, alters the stool-associated microbiota and the profiles of SCFAs and BAs. We used stool and plasma collected from patients enrolled in a single-sequence study using alirocumab. Microbial DNA was extracted from stool, and the bacterial component of the gut microbiota profiled following an amplicon sequencing strategy targeting the V3-V4 region of the 16S rRNA gene. Bile acids and SCFAs were profiled and quantified in stool and plasma using mass spectrometry. Treatment with alirocumab did not alter bacterial alpha (Shannon index, p = 0.74) or beta diversity (PERMANOVA, p = 0.89) in feces. Similarly, circulating levels of SCFAs (mean difference (95% confidence interval (CI)), 8.12 [-7.15-23.36] µM, p = 0.25) and BAs (mean difference (95% CI), 0.04 [-0.11-0.19] log10(nmol mg-1 feces), p = 0.56) were equivalent regardless of PCSK9 inhibition. Alirocumab therapy was associated with increased concentration of BAs in feces (mean difference (95% CI), 0.20 [0.05-0.34] log10(nmol mg-1 feces), p = 0.01). In statin-treated patients, the use of alirocumab to inhibit PCSK9 leads to elevated levels of fecal BAs without altering the bacterial population of the gut microbiota. The association of alirocumab with increased fecal BA concentration suggests an additional mechanism for the cholesterol-lowering effect of PCSK9 inhibition.

In vitro fermentation of substrates from Saccharina latissima by broiler chicken’s caecal microbiota

This study investigated seasonal variations in the composition of the kelp species Saccharina latissima cultivated on the Swedish west coast and, using an in vitro fermentation system, evaluated the effect of fermented whole S. latissima biomass or biomass components on the gut microbiota of broiler chickens. Caecal contents of six Ross 308 broilers fed a standard wheat and soy-based diet were retrieved on two different occasions, with three birds sampled per occasion. Two in vitro fermentation batches (A, B) were established using caecal contents as inoculum, and whole S. latissima, ethanol-washed S. latissima, laminarin extract or inulin (control) as substrate. Total short-chain fatty acid (SCFA) content, gas production, pH and changes in microbiota composition were studied after 6, 12 and 24 h of fermentation. Analysis of seasonal variations revealed that S. latissima harvested in June had the highest laminarin content and lowest ash and crude protein content. Broiler microbiota, SCFA profile, gas production and pH mainly varied depending on fermentation inoculum, but there were also some variations depending on substrate. For instance, uncultured bacterium from Clostridiales_vadinBB60_group showed higher relative abundance (RA) in batch A, while Faecalibacterium showed higher RA in batch B. Whole and ethanol-washed S. latissima resulted in highest RA of unclassified Ruminococcaceae and Tyzzerella for both batches, while ethanol-washed S. latissima and laminarin gave highest RA of Erysipelatoclostridium. Inulin resulted in highest RA for the genus Subdoligranulum. Acetic, n-butyric and propionic acid were the main fermentation products and total SCFA level was higher in batch B. Within batch B, inulin and laminarin generated higher levels of acetic and butyric acid. When using inulin and laminarin, gas production was lower in batch B compared with batch A. In summary, this study showed that S. latissima is a good source of laminarin, especially when harvested in summer. Within the in vitro system, the microbiota was affected by different substrates, but inoculum source was identified as an important contributor to microbial community development during fermentation.

Comparison of 3-nitrophenylhydrazine, O-benzyl hydroxylamine, and 2-picolylamine derivatizations for analysis of short-chain fatty acids through liquid chromatography coupled with tandem mass spectrometry.

Short-chain fatty acids (SCFAs) are metabolites derived from gut microbiota and implicated in host homeostasis. Hence, the profiling SCFAs from biological samples plays an important role in revealing the interaction between gut microbiota and pathogens. Previous studies, liquid chromatography-tandem mass spectrometry (LC-MS/MS) combined with various derivatization strategies have been performed to obtain the SCFA profiles from biological samples. However, it is poor evidence to compare these derivatization regents and conditions. Thus, we present the evaluation of three major derivatization reagents, namely 3-nitrophenylhydrazine (3-NPH), O-benzylhydroxylamine (O-BHA), and 2-picolylamine (2-PA), for the analysis of eight SCFAs classified as C2-C5 isomers using LC-MS/MS. First, in a reversed-phase LC separation, 3-NPH showed good retention capacity. Although O-BHA derivatization showed higher sensitivity and good retention capacity than 2-PA, only 2-PA derivatization could successfully separate eight SCFAs. The matrix effects in human serum ranged 77.1-99.0% (RSD ≤ 3.4%, n = 6) for 3-NPH derivatives, 91.0-94.6% (RSD ≤ 5.4%, n = 6) for O-BHA derivatives, 81.6-99.5% (RSD ≤ 8.0%, n = 6) for 2-PA derivatives. These compared results showed each characteristic of 3-NPH, O-BHA, and 2-PA for SCFA derivatization based on LC-MS/MS approaches.

Cutaneotrichosporon curvatum and Yarrowia lipolytica as key players for green chemistry: efficient oil producers from food waste via the carboxylate platform

ABSTRACT Cutaneotrichosporon curvatum and Yarrowia lipolytica can accumulate microbial oils using short-chain fatty acids (SCFA) as carbon sources. SCFAs-rich media often contain significant amounts of nitrogen that prevent high carbon:nitrogen (C:N) ratios necessary to boost lipid production. This work assessed the intrinsic ability of C. curvatum and Y. lipolytica to produce high amounts of microbial oils from these unusual carbon sources. Results demonstrated that minor differences in SCFA concentration (only 2 g/L) had a significant effect on yeast growth and lipid production. A C:N of 80 promoted yeast growth at all SCFA concentrations and favored SCFA consumption at 19 g/L SCFAs. The different SCFA uptake preferences in C. curvatum and Y. lipolytica highlighted the importance of considering the SCFA profile to select a suitable yeast strain for microbial oils production. At the most challenging SCFA concentration (19 g/L), 57.2% ±1.6% (w/w) and 78.4 ± 0.6% (w/w) lipid content were obtained in C. curvatum and Y. lipolytica, respectively. These values are among the highest reported for wild-type strains. To circumvent the challenges associated with media with high nitrogen content, this report also proved struvite precipitation as an effective method for increasing lipid production (from 17.9 ± 3.9% (w/w) to 41.9 ± 2.6% (w/w)) after nitrogen removal in food waste-derived media.

Pectin from Citrus unshiu Marc. Alleviates Glucose and Lipid Metabolism by Regulating the Gut Microbiota and Metabolites.

The effects of pectin from Citrus unshiu Marc. on glycolipid metabolism, the morphologies of the pancreas and epididymal fat, the gut microbiota, and the metabolites of short-chain fatty acids (SCFAs) in db/db mice were investigated in this study. The results indicated that pectin reduced the levels of fasting blood glucose, glycated serum protein, triglycerides, total cholesterol, and low-density lipoprotein cholesterol while increasing the levels of high-density lipoprotein cholesterol. Meanwhile, pectin could improve the morphology of islet cells and inhibit the hypertrophy of adipocytes. Additionally, pectin not only regulated the intestinal flora dysbiosis in db/db mice, as shown by the increasing proportion of Firmicutes/Bacteroidetes and the relative abundance of Ligilactobacillus, Lactobacillus, and Limosilactobacillus, but also remedied the metabolic disorder of SCFAs in db/db mice. These results suggest that pectin could promote glucose and lipid metabolism by regulating the intestinal flora with changes in SCFA profile. This study proves that pectin might serve as a new prebiotic agent to prevent the disorder of glycolipid metabolism.

In Vitro Fermentation Characteristics of Fungal Polysaccharides Derived from Wolfiporia cocos and Their Effect on Human Fecal Microbiota.

Gut microbiota has been described as a new 'organ' that interferes with host physiology by its metabolites produced from the utilization and biotransformation of undigested food components. Fu Ling (FL), the sclerotia of fungi Wolfiporia cocos, contains β-glucan, which is a known natural polysaccharide with strong medicinal efficacy. This study endeavors to evaluate the fermentability of FL and polysaccharides extracted from its sclerotia. An in vitro fermentation of structurally characterized FL and its β-glucan by human fecal microbiota was conducted. Total bacterial count, pH change, short-chain fatty acid profile and microbiota profile were assessed post-fermentation. FL containing over 70% of β-(1 → 3) and (1 → 6)-glucans with a low degree of branching of 0.24 could enhance acetic acid (a major microbial metabolite) production. Both FL and its extracted β-glucan had similar modulation on microbial composition. They enriched Phascolarctobacterium faecium, Bacteroides dorei and Parabacteroides distasonis, all of which are shown to possess anti-inflammatory effects. FL polysaccharide can be utilized as a natural whole food for its potential health benefits to human gut bacteria.

Midgut microbiota affects the intestinal barrier by producing short-chain fatty acids in Apostichopus japonicus.

The intestinal microbiota participates in host physiology and pathology through metabolites, in which short-chain fatty acids (SCFAs) are considered principal products and have extensive influence on intestine homeostasis. It has been reported that skin ulceration syndrome (SUS), the disease of Apostichopus japonicus caused by Vibrio splendidus, is associated with the alteration of the intestinal microbiota composition. To investigate whether the intestinal microbiota affects A. japonicus health via SCFAs, in this study, we focus on the SCFA profiling and intestinal barrier function in A. japonicus treated with V. splendidus. We found that V. splendidus could destroy the mid-intestine integrity and downregulate the expression of tight junction proteins ZO-1 and occludin in A. japonicus, which further dramatically decreased microorganism abundance and altered SCFAs contents. Specifically, acetic acid is associated with the largest number of microorganisms and has a significant correlation with occludin and ZO-1 among the seven SCFAs. Furthermore, our findings showed that acetic acid could maintain the intestinal barrier function by increasing the expression of tight junction proteins and rearranging the tight junction structure by regulating F-actin in mid-intestine epithelial cells. Thus, our results provide insights into the effects of the gut microbiome and SCFAs on intestine barrier homeostasis and provide essential knowledge for intervening in SUS by targeting metabolites or the gut microbiota.

Gastrointestinal Fermentable Polysaccharide Is Beneficial in Alleviating Loperamide-Induced Constipation in Mice.

To investigate the role of gastrointestinal (GI) polysaccharide fermentation in alleviating constipation, two polysaccharide fractions were isolated from a soluble fiber extract with determined anti-constipation activity: a 2.04 kDa neutral fraction (SSP-1) contained 99.29% glucose, and a 41.66 kDa acidic fraction (SSP-2) contained 63.85% uronic acid. After mice were given loperamide for 14 d to induce constipation, the GI transit rate increased significantly in the SSP-1 group (p < 0.05) but not in the SSP-2 group. The stool weight in the SSP-2 group was significantly higher than that in SSP-1 (383.60 mg vs. 226.23 mg) (p < 0.05). Both SSP-1 and SSP-2 groups had significantly increased serum gastrin and motilin levels (p < 0.05) and changes in their fecal short-chain fatty acid (SCFA) profiles, while SSP-1 showed better fermentation properties than SSP-2 in terms of statistically higher fecal contents of acetic acid and total SCFAs (p < 0.05). Bioinformatic analysis indicated that SSP-1 upregulated bacteria such as Oscillibacter to improve SCFA metabolism and stimulate GI hormone secretion, while SSP-2 had less influence on the gut microbiota. These results suggest that the neutral polysaccharide with superior GI fermentation properties exerted beneficial effects on constipation, while the less fermentable pectic fraction might act as a stool-bulking agent.