Short-chain fatty acid levels in stools of patients with inflammatory bowel disease are lower than those in healthy subjects.

OBJECTIVE: Short-chain fatty acids (SCFAs) are produced when the microbiota in the large intestine cause fermentation of dietary carbohydrates and fibers. These fatty acids constitute the primary energy source of colon mucosa cells and have a protective effect in patients suffering from inflammatory bowel disease (IBD). This study aimed to compare the SCFA levels in the stools of patients with IBD and healthy controls. METHOD: Healthy controls and patients with IBD aged 18 and over were included in the study. Stool samples from all patients and healthy controls were collected, and stool acetic acid, propionic acid, and butyric acid levels were measured using a gas chromatography-mass spectrometry measurement method. RESULTS: In this study, 64 participants were divided into two groups: 34 were in IBD (Crohn disease and ulcerative colitis) and 30 were in healthy control group. When fecal SCFA concentrations of IBD and healthy control groups were compared, a statistically significant difference was observed between them. When the fecal SCFA concentrations of Crohn's disease and ulcerative colitis patients in the IBD group were compared, however, no statistically significant difference was observed between them. Furthermore, when the participants' diet type (carbohydrate-based, vegetable-protein-based and mixed diet) and the number of meals were compared with fecal SCFA concentrations, no statistically significant difference was observed between them. CONCLUSION: In general, fecal SCFA levels in patients with IBD were lower than those in healthy controls. Moreover, diet type and the number of meals had no effect on stool SCFA levels in patients with IBD and healthy individuals.

Changes in Fecal Short-Chain Fatty Acids in IBS Patients and Effects of Different Interventions: A Systematic Review and Meta-Analysis.

CONTEXT: Short-chain fatty acids (SCFAs) have been reported to be associated with the pathogenesis of irritable bowel syndrome (IBS), but the results are conflicting. OBJECTIVE: Here, a systematic review of case-control studies detecting fecal SCFAs in IBS patients compared with healthy controls (HCs) and self-controlled studies or randomized controlled trials (RCTs) investigating fecal SCFA alterations after interventions were identified from several databases. DATA SOURCES: A systematic search of databases (PubMed, Web of Science, and Embase) identified 21 studies published before 24 February 2023. Data extractions: Three independent reviewers completed the relevant data extraction. DATA ANALYSIS: It was found that the fecal propionate concentration in IBS patients was significantly higher than that in HCs, while the acetate proportion was significantly lower. Low-FODMAP diets significantly reduced the fecal propionate concentration in the IBS patients while fecal microbiota transplantation and probiotic administration did not significantly change the fecal propionate concentration or acetate proportion. CONCLUSIONS: The results suggested that the fecal propionate concentration and acetate proportion could be used as biomarkers for IBS diagnosis. A low-FODMAP diet intervention could potentially serve as a treatment for IBS while FMT and probiotic administration need more robust trials.

Determination of 3-nitropropionic acid in sugarcane using dispersive solid-phase extraction and gas chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

A method for accurately determining 3-nitropropionic acid in sugarcane was established for the first time using gas chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (GC - APCI-MS/MS). Under acidic conditions, 3-nitropropionic acid is methylated to obtain methyl 3-nitropropionate. The derivative product was purified using dispersive solid-phase extraction (d-SPE) method and analyzed using GC - APCI-MS/MS. The recovery experiments were conducted at three concentrations: low, medium, and high. The recovery rates ranged from 75.1% to 90.2%, the relative standard deviations were <8.2%, and the limit of quantification was 2.0 µg/kg. The method offers the advantage of being accurate, sensitive, and specific, meeting the requirements of the determination of 3-nitropropionic acid in sugarcane.

Towards on-line cheese monitoring: Exploration of semi-hard cheeses using NIR and 1H NMR spectroscopy.

This study aims to investigate the potential of using advanced spectroscopies for cheese quality monitoring. For this purpose, six semi-hard cheeses manufactured using lactic acid bacteria (LAB) and/or propionic acid bacteria (PAB) were explored using near-infrared spectroscopy (NIRS) and Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy. The spectral data were analyzed using principal component analysis for extraction of possible discriminative patterns in quality parameters. The results show that the green analytical, but primarily bulk-sensitive, NIRS method was able to discriminate the cheese varieties primarily due to differences in the first overtone CH stretching region between 1650 and 1720 nm, in particular by the lactate methylene absorption at 1674 nm. A total of 25 metabolites were identified in the 1H NMR spectra of the cheese extracts, several of which were associated with the LAB and PAB metabolic pathways. PAB-associated metabolites include propionate, acetate, and glutamate, while LAB-associated metabolites include lactate and acetoin among others.

Metabolomic profile of seminal plasma from Guzerá bulls (Bos indicus) with contrasting sperm freezability phenotypes.

The present study evaluated the seminal plasma metabolome of Bos indicus Guzerá bulls with good (n = 4) and poor (n = 5) sperm freezability. Animals were raised in natural pasture of a 'Caatinga' ecosystem, in the semi-arid region of Brazil. Seminal plasma samples were subjected to gas chromatography coupled to mass spectrometry and data, analysed using bioinformatics tools (Cytoscape with the MetScape plug-in). Sixty-two metabolites were identified in the bovine seminal plasma. Fatty acids and conjugates and organic compounds were the predominant seminal fluid metabolites, followed by carboxylic acids and derivatives, amino acids, benzenes and steroids and derivatives, carbohydrates and carbohydrate conjugates and prenol lipids. Multivariate analysis indicated a distinct separation of seminal plasma metabolomes from bulls with contrasting sperm freezability. Abundances of propanoic acid, d-ribose and glycine were greater in the seminal plasma of bulls with good sperm freezability. Heptadecanoic acid and undecanoic acid were the predominant in bulls of poor sperm freezability. Propanoic acid is an energy source for spermatozoa and may act as an antimicrobial component in semen. Glycine acts against oxidizing and denaturing reactions. d-ribose is also an energy source and reduces apoptosis and oxidative stress. Undecanoic acid may protect sperm against fungal damage. This study provides fundamental information approximately the seminal plasma metabolome of tropically adapted bulls and its association with sperm freezability. However, further studies with larger groups of animals are needed to validate those metabolites as markers of sperm freezability. This strategy could support the selection of sires with superior sperm cryoresistance.

Feed intake and milk yield and composition of lactating dairy goats in response to partial substitution of soybean meal for formaldehyde-treated sesame meal in the diet.

This study was conducted to evaluate the effect of substitution of soybean meal (SBM) for formaldehyde-treated sesame meal (FTSM) on nutrient intake and digestibility, ruminal and blood parameters and milk production and composition in lactating Murciano-Granadina goats. Forty lactating goats were randomly assigned to one of the following four treatments: (1) diet with 16.5% CP, containing SBM (CON); (2) diet with 16.5% CP, containing untreated SM (USM); (3) diet with 16.5% CP, containing FTSM (FT); and (4) diet with 14.5% CP containing FTSM (LPFT). The results showed that nutrient intake was highest in the FT group (p < 0.001), while it was similar between the CON and LPFT groups, except for the intake of CP, which was higher in the CON group. The FT and LPFT had lower ruminal pH compared to CON and USM groups (p < 0.001), with goats in group FT having the highest volatile fatty acids (VFA) production (p < 0.001). The highest propionate concentration was observed in the LPFT treatment (p < 0.001), followed by the FT, CON, and USM treatments. Goats offered USM and LPFT treatments presented the highest and lowest acetate: propionate values, respectively, among the experimental groups (p < 0.001). The results also showed that LPFT goats had the lowest blood urea nitrogen (BUN) level (p = 0.004), while FT goats presented a lower non-esterified FA (NEFA) level compared with CON and LPFT goats (p = 0.01). Goats offered the FT diet had the highest milk yield (p = 0.002) and energy-corrected milk yield (p < 0.001) among all dietary groups. The highest milk fat (p < 0.001), protein (p = 0.001), lactose (p = 0.007), total solids (p = 0.003), and solids-not-fat (SNF) (p = 0.003) contents were observed in FT goats, which didn't differ from USM goats. The inclusion of formaldehyde-treated SM increased the percentage of C18:3 (p < 0.001) and C20:1 (p = 0.04) FAs compared with USM and CON treatments. Milk from USM, FT, and LPFT goats had lower levels of saturated (p < 0.001) and medium-chain FAs (p = 0.014) compared with CON goats, whereas milk from CON goats had lower levels of unsaturated, monounsaturated, and long-chain FAs compared to other groups (p < 0.001). The lowest and the highest concentrations of polyunsaturated FAs were observed in CON and LPFT goats, respectively (p = 0.001). It can be concluded that SBM can be advantageously replaced by formaldehyde-treated SM in the diet as a feasible alternative to improve feed intake and production performance of dairy goats.

Effects of dietary starch and ruminally undegraded protein on glucogenic precursors in lactating dairy cows.

Gluconeogenesis is a large contributor to the blood supply of glucose carbons. The impact of varying dietary starch and ruminally degraded protein (RDP) on glucose entry, and the contributions of propionate and lactate to total plasma glucose entry were evaluated. Six cannulated, lactating, Holstein cows were fed one of four treatment diets arranged as a 2 × 2 factorial within a 4 × 4 partially replicated Latin Square design: (1) 8% RDP (LRDP) and 16% starch (LSt), (2) LRDP and 30% starch (HSt), (3) 11% RDP (HRDP) and LSt, or (4) HRDP and HSt. On d 12 of each period, 2-[13C]-sodium propionate (0.15 g/h) was ruminally infused for 4 h; on d 13, 1,2-[13C2]-glucose (0.2 g/h) was infused into the jugular vein for 1 h followed by 1-[13C]-lactate (0.1 g/h) for 1 h. Blood samples were serially collected starting prior to the infusions, and analyzed for plasma glucose, propionate, and lactate isotopic ratios. A one-compartment, glucose carbon model with inputs from lactate, propionate, and other glucogenic precursors (Oth, primarily absorbed glucose plus amino acids) was fitted to the isotope ratio data to derive glucose entry rates and conversion of the precursors to glucose. Milk protein production additively increased when HSt and HRDP were fed (P = 0.05 and P = 0.02, respectively). Plasma glucose and propionate concentrations increased with HSt (P = 0.04 and P = 0.01, respectively) and LRDP (P = 0.02 and P < 0.01, respectively). Total glucose and Oth entry increased (P = 0.03 and P = 0.03, respectively) with HSt, indicating greater glucose absorption from the small intestine or conversion of amino acids to glucose in the liver. However, neither entry rate was affected by RDP. The lack of an RDP effect suggests the increase in microbial outflow in response to RDP did not significantly alter glucose precursor supplies. Entry rates of propionate and lactate carbon to glucose carbon were not affected by treatment suggesting that neither starch nor RDP significantly affected fermentation or lactate production. Derivation of absolute entry rates and contributions to glucose using isotopic tracers is complicated by single carbon removals in the pentose phosphate (PPP), tri-carboxylic acid (TCA), and gluconeogenic pathways, and label randomization with the PPP and TCA pathways. Multiple tracers must be used to avoid assumptions regarding the proportional entries. These results provide insights on glucose supply and contributors, and draw attention to significant label cycling when utilizing isotope techniques.

[The study of the content of short-chain fatty acids in the intestine of people with lipid metabolism disorders].

Dyslipidemias are a risk factor for cardiovascular diseases, especially at a young age. It is known from modern sources that shortchain fatty acids (SCFA) synthesized in the intestine are actively involved in the genesis of dyslipidemia, the spectrum and ratio of which depends on the consumed food substrates. In particular, it has been found that food components such as dietary fiber can affect the lowering of blood lipids by affecting the intestinal microbiota. Therefore, dietary correction can be an important step in the prevention and treatment of dyslipidemia, and as a result, help reduce the risk of developing cardiovascular disease (CD). The aim of the research was to study the content of the main SCFAs (acetate, propionate, butyrate) in the feces of people with dyslipidemia, including taking into account the actual nutrition and consumption of the carbohydrate fraction of the diet (starch, mono- and disaccharides, dietary fiber) as precursors of SCFAs. Material and methods. 70 patients aged 18 to 45 years with dyslipidemia were selected as stool donors. All subjects were divided into 2 groups: the main group with the risk of CD (the risk was determined by the risk scale for CD) and the comparison group with established cardiovascular pathology (CVP). SCFAs in stool samples collected after natural defecation and subjected to immediate freezing at -70 °C were determined by gas chromatography. The diet was analyzed by the 24-hour food recall method. Results. The frequency of occurrence of the optimal ratio acetate - acetic acid : propionate - propionic acid : butyrate - butyric acid (60:20:20) in all groups was no more than 25%. At the same time, in persons at risk of CD, in the SCFA pool there was a pronounced decrease in the proportion of butyrate, which is characterized by cardioprotective properties, up to 15% (with an optimal proportion of 20%) compared with the levels for healthy people noted in the works of M.D. Ardatskaya et al. and A.A. Kurmangulov. And in persons with CVP, the levels of fecal acetate, which is a regulator of metabolic processes, namely lipogenesis, differed insignificantly compared with the values obtained in the studies of the above authors. In all examined individuals, the content of acetate in feces depended on the carbohydrate component of the diet, primarily on the total amount of carbohydrates consumed. And increasing the amount of dietary fiber intake contributed to the elevation of this SCFA. In individuals at risk of CD a significant correlation was found between the content of acetate and the atherogenic index (r=0,695). And in persons with CVP, there was a high negative correlation between the level of acetate in the feces and the amount of mono- and disaccharides in the diet (r=-0,934). Conclusion. In individuals with dyslipidemia and CVD risk factors, the results obtained in this study confirm the need for targeted correction of diets in order to increase the proportion of food substrates, which are potential precursors of butyrate.

Prevalence of Novel and Traditional Synthetic Phenolic Antioxidants in Baby Food from China: A Dominant Pathway for Infant Exposure.

Synthetic phenolic antioxidants (SPAs) are a group of ubiquitous contaminants with multiple toxicities. However, current knowledge on the occurrence of SPAs in baby food and associated infant exposure is lacking. Herein, we analyzed three categories of baby food from China: infant formula, cereal, and puree, for a broad suite of 11 traditional and 19 novel SPAs. In addition to 11 traditional SPAs, up to 13 novel SPAs were detected in the baby food samples. The median concentrations of novel SPAs for infant formula, cereal, and puree were 604, 218, and 24.1 ng/g, respectively, surpassing those of traditional SPAs (53.4, 62.1, and 10.0 ng/g). The prevalent SPAs in the samples were butylated hydroxytoluene, 2,4-di-tert-butylphenol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (AO 1010), and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (AO 1076). Source analysis indicated that the prevalence of these four SPAs in baby food was associated with contamination of packaging materials, mechanical processing, or raw ingredients. Migration experiments demonstrated that contamination of plastic packaging constituted an important source. Exposure assessment suggested that there may be no appreciable health risk posed by the SPAs in baby food. Even so, baby food consumption was still a dominant pathway for infant exposure to SPAs, with a higher contribution than breast milk consumption, dust ingestion, dermal dust absorption, and air inhalation, which requires special attention.

HMOs Exert Marked Bifidogenic Effects on Children's Gut Microbiota Ex Vivo, Due to Age-Related Bifidobacterium Species Composition.

Prebiotics are substrates that are selectively utilized by host microorganisms, thus conferring a health benefit. There is a growing awareness that interpersonal and age-dependent differences in gut microbiota composition impact prebiotic effects. Due to the interest in using human milk oligosaccharides (HMOs) beyond infancy, this study evaluated how HMOs [2'Fucosyllactose (2'FL), Lacto-N-neotetraose (LNnT), 3'Sialyllactose (3'SL), 6'Sialyllactose (6'SL)] and blends thereof affect the microbiota of 6-year-old children (n = 6) and adults (n = 6), compared to prebiotics inulin (IN) and fructooligosaccharides (FOS). The ex vivo SIFR® technology was used, given its demonstrated predictivity in clinical findings. First, HMOs and HMO blends seemed to maintain a higher α-diversity compared to FOS/IN. Further, while 2'FL/LNnT were bifidogenic for both age groups, 3'SL/6'SL and FOS/IN were exclusively bifidogenic for children and adults, respectively. This originated from age-related differences in microbiota composition because while 3'SL/6'SL stimulated B. pseudocatenulatum (abundant in children), FOS/IN enhanced B. adolescentis (abundant in adults). Moreover, all treatments significantly increased acetate, propionate and butyrate (only in adults) with product- and age-dependent differences. Among the HMOs, 6'SL specifically stimulated propionate (linked to Bacteroides fragilis in children and Phocaeicola massiliensis in adults), while LNnT stimulated butyrate (linked to Anaerobutyricum hallii in adults). Indole-3-lactic acid and 3-phenyllactic acid (linked to immune health) and gamma-aminobutyric acid (linked to gut-brain axis) were most profoundly stimulated by 2'FL and HMO blends in both children and adults, correlating with specific Bifidobacteriaceae. Finally, 2'FL/LNnT increased melatonin in children, while 3'SL remarkably increased folic acid in adults. Overall, age-dependent differences in microbiota composition greatly impacted prebiotic outcomes, advocating for the development of age-specific nutritional supplements. HMOs were shown to be promising modulators in the adult, and particularly the children's microbiota. The observed HMO-specific effects, likely originating from their structural heterogeneity, suggest that blends of different HMOs could maximize treatment effects.

Enantioselective activity and toxicity of chiral acaricide cyflumetofen toward target and non-target organisms.

Cyflumetofen (CYF), a novel chiral acaricide, exert enantiomer-specific effects on target organisms by binding to glutathione S-transferase. However, there is limited knowledge regarding the response of non-target organisms to CYF, including enantioselective toxicity. In this study, we investigated the effects of racemic CYF (rac-CYF) and its two enantiomers (+)-CYF and (-)-CYF on MCF-7 cells and non-target (honeybees) and target (bee mites and red spider mites) organisms. The results showed that similar to estradiol, 1 µM (+)-CYF promoted the proliferation and disturbed the redox homeostasis of MCF-7 cells, whereas at high concentrations (≥100 µM) it exerted a negative effect on cell viability that was substantially stronger than that of (-)-CYF or rac-CYF. (-)-CYF and rac-CYF at 1 µM concentration did not significantly affect cell proliferation, but caused cell damage at high concentrations (≥100 µM). Analysis of acute CYF toxicity against non-target and target organisms revealed that for honeybees, all CYF samples had high lethal dose (LD50) values, indicating low toxicity. In contrast, for bee mites and red spider mites, LD50 values were low, whereas those of (+)-CYF were the lowest, suggesting higher toxicity of (+)-CYF than that of the other CYF samples. Proteomics profiling revealed potential CYF-targeted proteins in honeybees related to energy metabolism, stress responses, and protein synthesis. Upregulation of estrogen-induced FAM102A protein analog indicated that CYF might exert estrogenic effects by dysregulating estradiol production and altering estrogen-dependent protein expression in bees. Our findings suggest that CYF functions as an endocrine disruptor in non-target organisms in an enantiomer-specific manner, indicating the necessity for general ecological risk assessment for chiral pesticides.

Analysis of Fecal Short-Chain Fatty Acids (SCFAs) in Healthy Children during the First Two Years of Life: An Observational Prospective Cohort Study.

Short-chain fatty acids (SCFAs) are important metabolites of the gut microbiota. The aim is to analyze the influence of perinatal factors, which can affect the gut microbiota, on the concentrations of fecal SCFAs over the first two years of life. Gas chromatography was used to analyze SCFA in a total of 456 fecal samples from 86 children. Total SCFA concentrations increased until 12 months and stabilized after that. Antibiotic treatment during pregnancy was associated with an increase in acetic acid, propionic acid and total SCFA in meconium and a decrease in the same SCFAs at 6 months. Butyric acid was increased after Caesarean delivery until 1 month. In formula-fed children, propionic acid (at 1 month) and butyric acid and total SCFA (at 12 months) were increased. Acetic and linear butyric acids and total SCFAs were also increased at 12 months in children born vaginally that were also formula-fed. Higher butyric acid was observed in children of mothers with normal pre-pregnancy weight and adequate weight gain during pregnancy. Butyric acid was also elevated in 6-month-old infants with a higher body weight (≥85th percentile). Acetic acid concentrations were significantly higher in 2-year-old females vs. males. We conclude that perinatal factors are linked to changes in fecal SCFAs and further long-term epidemiological studies are warranted.

Breastfeeding might partially contribute to gut microbiota construction and stabilization of propionate metabolism in cesarean-section infants.

PURPOSE: This study was aimed to determine how delivery mode and feeding pattern influence the infant's gut microbiota construction and the variation of fecal microbial metabolites from a birth cohort. METHODS: Fecal samples collected from 61 full-term born Chinese infants at four time points: day 0, day 7, month 1, and month 3. Based on delivery mode (vaginal delivery [V] or cesarean section [C]) and feeding pattern (breastfeeding [B] or mixed feeding [M]), infants were divided into four groups, namely VB, CB, VM, and CM groups. The gut microbiota composition and bacterial diversity were assessed using 16S rRNA sequencing. Short-chain fatty acid (SCFA) concentrations were determined via gas chromatography-mass spectrometry (GC-MS). RESULTS: The CM group had a significantly higher relative abundance of Firmicutes (day 0 and month 1), Enterococcaceae (month 3), and Enterococcus (month 3) than the VB group and a significantly higher abundance of Firmicutes (month 1) and Blautia (month 3) than the CB group. The VB and CB groups exhibited a stable SCFA variation and a significantly lower level of propionate compared with the VM and CM groups. All groups showed an intense transition of enterotypes within 1 month and became stable at 3 months. The correlation between SCFA and enterotypes showed a significant positive correlation between Bifidobacteriaceae and acetate in the CB group (day 7 and month 3) and a significant positive correlation between Clostridiaceae and butyrate in the CB and VB groups (day 7 and month 3), respectively. CONCLUSION: These results indicated that C-section was associated with higher abundance of the phylum Firmicutes and family Enterococcaceae, and intense fluctuation of SCFA, at least propionate. And breastfeeding might partially contribute to gut microbiota construction and stabilization propionate metabolism in cesarean-section infants.

Genetic Predictors for Fecal Propionate and Butyrate-Producing Microbiome Pathway Are Not Associated with Colorectal Cancer Risk: A Mendelian Randomization Analysis.

BACKGROUND: Mechanistic data indicate the benefit of short-chain fatty acids (SCFA) produced by gut microbial fermentation of fiber on colorectal cancer, but direct epidemiologic evidence is limited. A recent study identified SNPs for two SCFA traits (fecal propionate and butyrate-producing microbiome pathway PWY-5022) in Europeans and showed metabolic benefits. METHODS: We conducted a two-sample Mendelian randomization analysis of the genetic instruments for the two SCFA traits (three SNPs for fecal propionate and nine for PWY-5022) in relation to colorectal cancer risk in three large European genetic consortia of 58,131 colorectal cancer cases and 67,347 controls. We estimated the risk of overall colorectal cancer and conducted subgroup analyses by sex, age, and anatomic subsites of colorectal cancer. RESULTS: We did not observe strong evidence for an association of the genetic predictors for fecal propionate levels and the abundance of PWY-5022 with the risk of overall colorectal cancer, colorectal cancer by sex, or early-onset colorectal cancer (diagnosed at <50 years), with no evidence of heterogeneity or pleiotropy. When assessed by tumor subsites, we found weak evidence for an association between PWY-5022 and risk of rectal cancer (OR per 1-SD, 0.95; 95% confidence intervals, 0.91-0.99; P = 0.03) but it did not surpass multiple testing of subgroup analysis. CONCLUSIONS: Genetic instruments for fecal propionate levels and the abundance of PWY-5022 were not associated with colorectal cancer risk. IMPACT: Fecal propionate and PWY-5022 may not have a substantial influence on colorectal cancer risk. Future research is warranted to comprehensively investigate the effects of SCFA-producing bacteria and SCFAs on colorectal cancer risk.

Short-chain fatty acids profiling in biological samples from a mouse model of Sjögren's syndrome based on derivatized LC-MS/MS assay.

An analytical platform is required to characterize the short-chain fatty acids (SCFAs) in a mouse model of pathological immune conditions. Therefore, liquid chromatography tandem mass spectrometry combined with 2-picolylamine derivatization and a comprehensive study of SCFAs distribution based on serum, saliva, feces, liver, and brain from a mouse model of Sjögren's syndrome (SS) is performed. The design of experiments is used to achieve efficient 2-picolylamine derivatization, and optimize the reaction conditions. Twelve SCFAs are derivatized, and separated on a reversed-phase C18 column. All SCFAs show high linearity (r2 > 0.995) and intra/inter-day accuracy values from 71.6% to 115.6% (precision < 13.7%). This method was used to determine SCFAs concentrations in the serum, saliva, feces, liver, and brain of an SS model mice, and isobutyric acid, valeric acid, isovaleric acid, and 2-methylbutyric acid in liver from SS were significantly different compared with control group. Moreover, the preliminary evaluation of propionic acid, butyric acid, isobutyric acid, valeric acid, and isovaleric acid in saliva is conducted based on the respective SS stages and are correlated with these histological scores. This analytical platform for the widely SCFAs profiling in several tissues can be a clue for studying unclear immune pathophysiology.

Coevolution of Rumen Epithelial circRNAs with Their Microbiota and Metabolites in Response to Cold-Season Nutritional Stress in Tibetan Sheep.

This study explores the effects of the coevolution of the host genome (the first genome) and gut microbiome (the second genome) on nutrition stress in Tibetan sheep during the cold season. The rumen epithelial tissue of six Tibetan sheep (Oula-type) was collected as experimental samples during the cold and warm seasons and the study lasted for half a year. The cDNA library was constructed and subjected to high-throughput sequencing. The circRNAs with significant differential expression were identified through bioinformatics analysis and functional prediction, and verified by real-time quantitative PCR (qRT-PCR). The results showed that a total of 56 differentially expressed (DE) circRNAs of rumen epithelial tissue were identified using RNA-seq technology, among which 29 were significantly upregulated in the cold season. The circRNA-miRNA regulatory network showed that DE circRNAs promoted the adaptation of Tibetan sheep in the cold season by targeting miR-150 and oar-miR-370-3p. The results of correlation analysis among circRNAs, microbiota, and metabolites showed that the circRNA NC_040275.1:28680890|28683112 had a very significant positive correlation with acetate, propionate, butyrate, and total volatile fatty acid (VFA) (p < 0.01), and had a significant positive correlation with Ruminococcus-1 (p < 0.05). In addition, circRNA NC_040256.1:78451819|78454934 and metabolites were enriched in the same KEGG pathway biosynthesis of amino acids (ko01230). In conclusion, the host genome and rumen microbiome of Tibetan sheep co-encoded a certain glycoside hydrolase (ß-glucosidase) and coevolved efficient VFA transport functions and amino acid anabolic processes; thus, helping Tibetan sheep adapt to nutrient stress in the cold season in high-altitude areas.

Effect of Inoculation with Lentilactobacillus buchneri and Lacticaseibacillus paracasei on the Maize Silage Volatilome: The Advantages of Advanced 2D-Chromatographic Fingerprinting Approaches.

In this study, the complex volatilome of maize silage samples conserved for 229 d, inoculated with Lentilactobacillus buchneri (Lbuc) and Lacticaseibacillus paracasei (Lpar), is explored by means of advanced fingerprinting methodologies based on comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry. The combined untargeted and targeted (UT) fingerprinting strategy covers 452 features, 269 of which were putatively identified and assigned within their characteristic classes. The high amounts of short-chain free fatty acids and alcohols were produced by fermentation and led to a large number of esters. The impact of Lbuc fermentation was not clearly distinguishable from the control samples; however, Lpar had a strong and distinctive signature that was dominated by propionic acid and 1-propanol characteristic volatiles. The approach provides a better understanding of silage stabilization mechanisms against the degradative action of yeasts and molds during the exposure of silage to air.

Improving the specificity of E. coli acetate/propionate exclusion biosensors via iterative engineering.

Real-time monitoring of key performance indicator analytes such as acetate and propionate within anaerobic digestors (AD) is required for optimum biogas production. In this paper the further refinement of acetate and propionate whole cell (E. coli) exclusion biosensors is reported following an iterative process in which key metabolites that might interfere with O2-uptake measurements are identified and genes required for their catabolism are knocked out (exclusion). Analysis of biological leachate from an AD reactor treating lignocellulosic material revealed the presence of formate, which was subsequently shown to elicit a response in previously developed E. coli biosensor strains. P1 phage transduction was employed to delete two genes encoding formate dehydrogenase, fdoH and fdnH, to eliminate formate catabolism. Deletion of these genes from the propionate biosensor strain W:ldgyepak abolished interference from formate and enabled accurate determination of propionate concentrations in biological leachate. However, the acetate biosensing strain E1/pGDR11-acs, despite not having any response to formate, responded to propionate. It was likely that this was a result of the promiscuity of the wild type acetyl CoA synthetase, which was replaced with Acs2 from Saccharomyces cerevisiae, resolving the problem and enabling acetate determination with the biosensor. Acetate and propionate concentrations in authentic leachate influent were estimated to be 26.5 mM and 65.5 mM, respectively, using the biosensor, and 26.6 and 70 mM, respectively, by HPLC, demonstrating the accuracy and specificity of the refined biosensor.

Parkinson's Disease Is Associated with Impaired Gut-Blood Barrier for Short-Chain Fatty Acids.

BACKGROUND: Short-chain fatty acids (SCFAs) produced by gut microbiota are reduced in feces but paradoxically increased in plasma of patients with Parkinson's disease (PD), which may stem from intestinal wall leakage. Gut function should be taken into consideration when conducting microbial-metabolite research. OBJECTIVE: The objective was to investigate synchronous changes of SCFAs in feces and plasma of patients with PD, taking constipation as a confounder to better disentangle the SCFA metabolism exclusively associated with PD. METHODS: The concentrations of fecal and plasma SCFAs in 33 healthy control subjects and 95 patients with PD were measured using liquid and gas chromatography mass spectrometry, respectively. Patients with PD were divided into patients with PD without constipation (n = 35) and patients with PD with constipation (n = 60). Gut-blood barrier (GBB) permeability was assessed by plasma/fecal ratio of SCFA concentrations and fecal α1-antitrypsin concentration. RESULTS: Patients with PD displayed decreased concentrations of fecal acetic, propionic, and butyric acid and increased concentrations of plasma acetic and propionic acid. Fecal acetic, isobutyric, and isovaleric acid were lower and plasma acetic and propionic acid were higher in patients with PD with constipation than in patients with PD without constipation. Constipation aggravated GBB permeability in patients with PD. Combined fecal and plasma SCFAs could discriminate patients with PD from healthy control subjects. Fecal SCFAs, except propionic acid, were negatively correlated with disease severity, while plasma acetic, propionic, and valeric acid showed a positive correlation. CONCLUSIONS: Our study showed alterations of fecal and plasma SCFAs in patients with PD that were associated with an impaired GBB and might be aggravated by constipation. © 2022 International Parkinson and Movement Disorder Society.

Effects of the higher concentrate ratio on the production performance, ruminal fermentation, and morphological structure in male cattle-yaks.

BACKGROUND: The present study evaluated the effects of the different concentrate-to-forage ratio on the parameters of production, ruminal fermentation, blood biochemical indices, and ruminal epithelial morphological structure of the male cattle-yaks. METHODS: Eight male cattle-yaks (280 ± 10 kg of body weight) were randomly divided into the high concentrate (HighC, 70% concentrate feeds on a dry matter basis) and low concentrate (LowC, 50% concentrate feeds on a dry matter basis) groups. All the animals were regularly provided rations twice a day at 08:00 and 16:00 h and had free access to water. The experiment lasted for 37 days. RESULTS: The dry matter intake and average daily gain of the HighC group were higher (p < 0.05) than those of LowC group. Moreover, a high concentrate diet was found to significantly increase (p < 0.05) the total volatile fatty acid (TVFA) production, and the ratio of propionate and butyrate in TVFA. On the contrary, the ruminal pH, the ratio of isobutyrate and isovalerate, and the acetate-to-propionate were significantly decreased (p < 0.05) after high concentrate feeding. The lipopolysaccharide concentrations of the ruminal fluid and plasma in the HighC group were higher (p < 0.05) than those of the LowC group. The results of the ruminal histomorphology showed the rumen to possess an inflammatory reaction. CONCLUSION: These findings revealed that upon higher dry matter intake and average daily gain, high concentrate feeding altered the rumen fermentation and morphology, inducing the ruminal inflammation of the cattle-yak.