Search Results (1,470)

The gut microbiota and its metabolic functions are critical for intestinal homeostasis, but their integrated responses to diarrhea remain poorly understood in non-model mammals, such as the complex-toothed flying squirrel (Trogopterus xanthipes). Here, we collected fecal samples from six captive animals with diarrhea and six healthy controls; the diarrheal animals had been provided with moldy corn, but mycotoxin levels were not measured. Fecal microbiota was profiled by full-length 16S rRNA sequencing and untargeted metabolomics with integrative analyses. Diarrheal animals showed significantly decreased fecal microbial alpha-diversity and distinct community separation. LEfSe analysis identified Lawsonia intracellularis and Streptococcus macedonicus as the most enriched taxa in the diarrhea group. Untargeted metabolomics revealed 2216 differential metabolites (1931 downregulated), primarily enriched in steroid hormone biosynthesis, arachidonic acid metabolism, and bile secretion pathways. Procrustes and Mantel tests confirmed significant microbiome–metabolome concordance (M² = 0.422, p < 0.001). Spearman correlation networks showed that L. intracellularis was positively correlated with multiple differential metabolites, while S. macedonicus exhibited predominantly negative correlations. These findings suggest that diarrhea in T. xanthipes may be associated with moldy corn exposure and is accompanied by gut dysbiosis and metabolic disturbances. L. intracellularis and S. macedonicus may be associated with disease progression through pathways linked to lipid and bile acid metabolism and inflammation. This study provides novel microbial–metabolic insights into diarrhea in a medicinal mammal, supporting disease prevention and healthy breeding. Full article

This study investigated the effects of dietary protein levels and arginine supplementation on growth performance, nitrogen metabolism, serum biochemical indices, inflammatory markers, gut microbiota, and fecal metabolomic profiles in growing beagles. Sixty healthy beagles were assigned to six dietary treatments in a 2 × 3 factorial design: two crude protein levels (normal, 22%; low, 18%) and three arginine supplementation levels (0%, 0.266%, 0.532%) over 45 days. Growth performance and nutrient digestibility were not significantly affected by diet. Low-protein diets reduced nitrogen intake and excretion while increasing biological value, indicating improved nitrogen utilization. Serum total cholesterol, blood urea nitrogen, and creatinine were influenced by protein and arginine levels, and inflammatory markers TNF-α and IL-6 were modulated by their interaction. Gut microbiota composition was altered at the taxonomic level but not at the level of the overall structure; arginine supplementation increased microbial richness under normal protein conditions. Fecal metabolomic analysis showed that arginine mainly affected amino acid metabolism, mineral absorption, and bile acid pathways, whereas protein reduction impacted lipid metabolism, bile secretion, and energy-related pathways. Overall, reducing dietary protein to 18% improved nitrogen utilization without impairing growth. Among the six dietary treatments, the normal-protein diet supplemented with moderate arginine (22% CP + 0.266% L-arginine, 1.10% total arginine) was associated with the most balanced overall physiological response. Metabolomic findings from the four selected dietary groups provided additional evidence that dietary protein and arginine modulated distinct metabolic pathways, although these findings should be interpreted within the scope of the selected-group comparison. These results provide a practical basis for optimizing amino acid balance and nitrogen utilization in growing dogs and may contribute to the development of more precise and sustainable pet food formulations. Full article

This review systematically summarizes the metabolic transformation patterns, bioavailability regulation mechanisms, and multi-target host health effects of honey phenolic compounds under the action of gut microbiota, based on literature from 1996 to 2026. It focuses on elucidating the “high efficacy in vitro, low exposure in vivo” paradox, the three-step cascade metabolic pathway (deglycosylation, C-ring cleavage, and reduction with secondary transformation), and the synergistic prebiotic effects of “oligosaccharides plus phenolics.” Current evidence indicates that the health benefits of honey are largely derived from microbiota-derived small-molecule metabolites rather than from the parent compounds, and these metabolites exert regulatory effects via the gut–liver, gut–brain, gut–immune, and gut–fat axes. However, the vast majority of evidence comes from in vitro fermentation, animal models, or ex vivo fecal cultures, with a severe shortage of high-quality human intervention studies, thereby limiting causal inference. Therefore, this review proposes a shift in honey quality evaluation from traditional qualitative chemical composition-based assessment toward precision functional evaluation based on metabolite profiles, and emphasizes the urgent need to establish standardized metabolite-based quality markers, develop enterotype-based stratified nutrition strategies, and conduct rigorous randomized controlled trials, so as to promote the transformation of honey from a traditional food into a targeted dietary intervention agent. Full article

Cyanotoxin events are among the most serious consequences of cyanobacterial harmful algal blooms. Microcystins (MCs), among the most prevalent cyanotoxins, are known to adversely affect human health. Recently, respiratory exposure has emerged as an important exposure route for MCs, with potential downstream effects on the gut microbiome through the lung–gut axis. In this pilot study, we investigated acute respiratory immune responses and gut microbiome alterations following MC inhalation using female C57BL/6J mice. Mice were assigned to three dose groups: control (0 µg/kg body weight), medium (25 µg/kg), and high (50 µg/kg). MC-LR was administered intranasally once daily for 3 days. Fecal samples were collected daily for 16S rRNA sequencing, and bronchoalveolar lavage (BAL) fluids were collected following sacrifice for immune cell analysis. MC exposure resulted in significantly increased monocyte counts (p < 0.1), while neutrophil, macrophage, and total cell counts did not significantly change (p > 0.1), suggesting selective lower respiratory tract inflammation. Functional prediction analysis of gut microbiota revealed significant increases (p < 0.1) in pathways associated with host health, including heme biosynthesis, sulfur oxidation, carbon metabolism, and antibiotic resistance. These findings suggest that inhaled MCs may induce respiratory inflammation and contribute to gut microbiome dysbiosis via the lung–gut axis. Full article

(1) Objective: To characterize structural and functional alterations of gut microbiota in patients with newly diagnosed active pulmonary tuberculosis (ATB), screen differential bacterial taxa associated with Mycobacterium tuberculosis (MTB) infection, and explore tuberculosis-related microbial metabolic alterations via predictive functional profiling. (2) Methods: Fresh morning fecal samples were collected from 33 treatment-naive patients with newly diagnosed ATB (ATB group) and 30 healthy controls (HC group). 16S rRNA gene high-throughput sequencing was performed to compare intergroup differences in gut microbial α/β diversity, taxonomic composition, and predicted KEGG functional profiles. Receiver operating characteristic (ROC) curve analysis was conducted to evaluate the internal discriminative ability of candidate differential genera in this single small cohort. (3) Results: The ATB group showed significantly lower gut microbial α-diversity than healthy controls (all P < 0.05). Principal coordinate analysis (PCoA) based on Bray-Curtis distances combined with permutational multivariate analysis of variance (PERMANOVA) revealed significant overall dissimilarity of gut microbial community structure between the two groups (R² = 0.31, p = 0.005). At the phylum level, the relative abundances of Firmicutes and Bacteroidetes were higher, while Proteobacteria was less abundant in ATB patients relative to HC. At the genus level, Streptococcus, R. gnavus and Parabacteroides were significantly enriched in ATB patients, whereas Bifidobacterium, Pseudomonas, Megamonas and Faecalibacterium were depleted. Linear discriminant analysis effect size (LEfSe) analysis uncovered group-specific signature taxa, with pro-inflammatory genera Streptococcus and R. gnavus markedly enriched in the ATB group. ROC analysis yielded area under the curve (AUC) values of 0.836 for Streptococcus and 0.805 for R. gnavus. Predictive KEGG functional analysis demonstrated obvious intergroup differences in microbial metabolism, with purine and pyrimidine nucleotide metabolism pathways significantly upregulated in the ATB group. (4) Conclusions: Treatment-naive patients with ATB exhibited reduced gut microbial diversity in this small cohort. The enrichment of Streptococcus and R. gnavus, as well as the upregulation of purine and pyrimidine metabolic pathways, are all associated with active MTB infection. Full article

Background/Objectives: Functional bowel disorders (FBDs) are chronic gastrointestinal conditions that substantially impair quality of life. This randomized, double-blind, placebo-controlled trial investigated the effects of Heyndrickxia coagulans IDCC 1201 (COA 1201) in adults with FBD. Methods: Participants received COA 1201 or a placebo for 8 weeks, with outcomes assessed using the irritable bowel syndrome (IBS) Symptom Severity Score (IBS-SSS), IBS Quality of Life (IBS-QOL), and bowel activity measures. And Fecal microbiome and metabolomics were measured by 16S rRNA gene sequencing gas chromatography-mass spectrometry, respectively. Results: Both groups showed improvement from baseline, but COA 1201 produced greater symptom relief, particularly in abdominal bloating, post-defecation discomfort, and the body image domain of IBS-QOL. Fecal microbiome profiling revealed modest changes in global diversity, yet taxa linked to saccharolytic activity and short-chain fatty acid production—including Ruminococcus bromii, Agathobacter rectalis, and Bifidobacterium—were enriched in participants receiving COA 1201, whereas Clostridium leptum increased in those receiving a placebo. Untargeted metabolomics demonstrated distinct metabolic signatures between groups, confirmed by supervised partial least squares discriminant analysis. Exploratory metabolites were identified using variable importance in projection scores (>1.5), statistical significance (p < 0.05), and absolute log₂ fold change (>1). Alanine and proline emerged as time-dependent metabolites, while tryptophan, lactic acid, and phytosphingosine were specifically associated with COA 1201 treatment. Conclusions: Collectively, these findings suggest that COA 1201 alleviates FBD symptoms by modulating the gut microbiome and metabolome. Full article

Background/Objectives: Raffinose is a prebiotic trisaccharide fermented by human gut microbiota, yet the strain-level determinants of its degradation and associated metabolic outputs remain poorly characterized. Methods: In the present study, anaerobic fermentation, 16S rRNA gene amplicon high-throughput sequencing, culturomics, and metabolomics were conducted to address this question. Results: In vitro fermentation of raffinose was performed using fecal samples from 16 healthy donors, and substantial interindividual variation was observed in substrate consumption, microbiota composition, and short-chain fatty acid production. Through culturomics, 204 bacterial strains spanning 18 species were isolated, among which Limosilactobacillus reuteri subsp. reuteri exhibited the highest raffinose-degrading efficiency. Untargeted metabolomics comparing L. reuteri subsp. reuteri cultured on raffinose versus glucose revealed a distinct metabolic shift, with 290 metabolites significantly upregulated, including the putatively identified fructooligosaccharide 1-kestose—a compound with documented prebiotic and anti-inflammatory properties. KEGG enrichment further highlighted coordinated remodeling of nucleotide and amino acid metabolism. Conclusions: Collectively, this study provides a strain-level framework for understanding how raffinose shapes the gut microbiota and identifies L. reuteri subsp. reuteri as a key metabolic hub linking prebiotic consumption to the production of bioactive metabolites. Full article

Oral lichen planus (OLP) is a chronic inflammatory oral disease associated with immune dysregulation and malignant transformation risk. Vitamin D and probiotics may modulate immune and microbial pathways involved in OLP. In this study, we evaluated their effects on clinical outcomes and multi-omics profiles in 25 adult OLP patients (median age: 68 years). Vitamin D-deficient patients received 2000 IU/day vitamin D3, and all participants received a probiotic blend (Limosilactobacillus reuteri LRE11, Lacticaseibacillus rhamnosus LR04, and Lacticaseibacillus casei LC04) for 16 weeks. Clinical assessments and analyses of saliva, serum, oral swabs, and stool samples were performed before and after treatment. Clinical outcomes improved significantly, with reductions in lesion number (p < 0.001), lesion size (p = 0.004), and bleeding lesions (p = 0.014); 76% of patients were classified as in remission. Vitamin D levels increased significantly among deficient patients receiving correction (p < 0.01). Salivary and fecal metabolomics showed significant remodeling of amino acid and carbohydrate pathways, including decreases in branched-chain amino acids in saliva and modulation of nicotinamide- and amino acid-related metabolites in feces. Microbiome α-diversity remained stable, whereas β-diversity shifted significantly across oral and fecal sites, with enrichment of Lacticaseibacillus and other context-dependent commensals. Multi-omics integration identified three latent factors linking salivary cytokines, microbial taxa, metabolites, and systemic lipid profiles, suggesting coordinated mucosal–metabolic–immune remodeling across the oral–gut axis. Full article

Glycyrrhizic acid (GL), a natural triterpenoid glycoside extracted from the “medicine food homology” herb Glycyrrhiza glabra L., exhibits potent anti-atherosclerotic effects; yet its underlying mechanisms remain unclear due to its poor oral bioavailability. The gut microbiota plays a pivotal role in the development of atherosclerosis (AS). In this study, the microbiota-dependent anti-AS effects of GL were evaluated in high-fat diet (HFD)-fed ApoE^−/− mice using antibiotic depletion and fecal microbiota transplantation (FMT). Integrated metagenomic and metabolomic analyses were performed to identify the key bioactive microbial metabolite. Further in vivo and in vitro experiments, including co-immunoprecipitation and dual-luciferase reporter assays, were utilized to elucidate the underlying molecular mechanisms. It was demonstrated that oral administration of GL alleviated AS in a microbiota-dependent manner by reversing gut dysbiosis, improving intestinal barrier function, and reducing pro-inflammatory lipopolysaccharide (LPS) levels. GL shifted intestinal tryptophan metabolism toward bacterial-derived indole-3-lactic acid (ILA) production, suppressing LPS-induced vascular endothelial adhesion dysfunction by activating the aryl hydrocarbon receptor (AhR). Mechanistically, ILA-activated AhR interacted with the NF-κB subunit p65 in the cytoplasm, effectively preventing the nuclear translocation of p65 and suppressing the promoter activities of adhesion molecules (VCAM1 and ICAM1), resulting in the amelioration of HFD-induced AS. These findings elucidate the microbiota-dependent mechanism of orally administered GL against AS, and highlight the therapeutic potential of targeting the ILA-AhR-p65 axis in the vascular endothelium as a strategy for AS. Full article

Background/Objectives: Gut dysbiosis in children with autism spectrum disorder (ASD) has been associated with alterations in microbial ecology and metabolic function that may contribute to gastrointestinal dysfunction and the severity of clinical manifestations. Synbiotic and probiotic supplementation has emerged as a promising microbiome-targeted strategy for ASD; however, its effects on gut microbiome composition, functional potential, and clinical outcomes remain incompletely understood. We conducted a longitudinal study of Mexican children diagnosed with ASD to analyze changes in the composition, diversity, and functional potential of the gut microbiome during six months of multi-strain synbiotic supplementation. Methods: Stool samples were collected from 25 children with ASD at baseline and after 3 and 6 months of multi-strain synbiotic supplementation. Gut microbiome composition and diversity were analyzed by 16S rRNA gene sequencing, whereas whole metagenome sequencing (WMS) was performed in a subset of samples to evaluate the functional potential of the fecal microbiome. Gastrointestinal symptoms were assessed using the Rome IV criteria, and ASD severity was evaluated with the Childhood Autism Rating Scale (CARS). Results: Twenty-five children with ASD completed the 6 months of synbiotic supplementation. Overall, ASD severity decreased, reflected by a reduction in total CARS score, and improvements in several CARS domains. Gastrointestinal symptoms also decreased significantly. Longitudinal microbiome profiling revealed significant taxonomic and diversity changes over the supplementation period, while WMS identified changes in microbial metabolic potential, including enrichment of tryptophan biosynthesis pathways and reduced L-rhamnose degradation. Conclusions: This exploratory research provides proof-of-concept evidence supporting multi-strain synbiotic supplementation in children with ASD. Larger controlled studies are needed to confirm these findings and clarify their relevance to microbiota–gut–brain axis interactions. The observed concordance between clinical improvements and microbiome remodeling supports further investigation of microbiome-targeted interventions according to ASD severity and duration of supplementation. Full article

This study evaluated the short-term response of the fecal microbiota of wild Cavia tschudii during its transition from natural conditions to captivity under a standardized alfalfa-based diet. Fecal samples were collected over a 21-day period and analyzed using 16S rRNA gene sequencing to assess microbial diversity, community structure, and taxonomic composition. Rarefaction analysis indicated sufficient sequencing coverage; however, samples were normalized to 500 reads per sample, and results should be interpreted cautiously. No significant changes were detected in alpha diversity, beta diversity, or dominant taxonomic composition across sampling time points. The microbiota was consistently dominated by Bacteroidota and Firmicutes, accounting for more than 85% of total relative abundance. Minor taxa such as Methanobacteriales and Spirochaetales were present at low and stable abundances. Despite differences between natural forage and the alfalfa-based diet, microbial community structure showed limited temporal variation during the study period. The absence of detectable parasitic infections further supports that observed patterns reflect host–microbiota dynamics under controlled conditions. Functional predictions suggested variation in metabolic pathways but should be interpreted cautiously due to the limitations of 16S rRNA-based inference. Overall, these findings suggest limited temporal variation in the fecal microbiota of Cavia tschudii during the first three weeks of captivity under the conditions evaluated. However, due to the exploratory nature of the study and its methodological limitations, these results should be interpreted with caution. This study provides baseline insights into limited temporal variation in the fecal microbiota of a wild caviid species and contributes to understanding host–microbiome interactions relevant to conservation and potential domestication processes. Full article

Metabolic syndrome (MetS) is a multifactorial disorder characterized by central obesity, insulin resistance, dyslipidemia, hypertension, and impaired glucose metabolism, significantly increasing the risk of type 2 diabetes and cardiovascular disease. Recent evidence highlights the important role of the gut–brain axis in the pathogenesis of MetS through complex interactions between the gut microbiota, immune system, endocrine signaling, and host genetics. This narrative review provides an integrative overview of the mechanisms linking dysbiosis to metabolic dysfunction, with particular emphasis on gut microbiota alterations, intestinal permeability, chronic low-grade inflammation, and microbial metabolites such as short-chain fatty acids and lipopolysaccharides. The review also discusses the neural, endocrine, and immune pathways involved in gut–brain communication, including the role of gut-derived neurotransmitters in metabolic regulation. In addition, the contribution of host genetic susceptibility and epigenetic regulation is explored, highlighting how gene–microbiome interactions influence individual metabolic responses and disease risk. Recent advances in multi-omics technologies and precision medicine suggest that personalized approaches targeting both microbial and genetic factors may improve prevention and treatment strategies for MetS. Furthermore, microbiota-targeted interventions, including dietary modifications, probiotics, prebiotics, and fecal microbiota transplantation, are discussed as emerging therapeutic perspectives. Overall, this review emphasizes the importance of considering MetS as a systemic disorder driven by interconnected biological networks involving microbiota, metabolism, immunity, and genetics. Full article

Probiotics are promising alternatives to antibiotics in calf rearing, but effects of Lactobacillus species combined with Bacillus subtilis on preweaning development remain unclear. Two probiotic consortia—L. plantarum + B. subtilis (TG1) vs. L. acidophilus + B. subtilis (TG2)—were compared in Holstein calves. Forty-eight newborn calves (initial BW 37.0 ± 2.7 kg) were randomly assigned to control (CG) or probiotic groups (TG1, TG2) from day 3 for 60 days. Growth, fecal scores, serum biochemistry, antioxidant/immune indices, rumen fermentation, 16S rRNA, and untargeted metabolomics were measured. Compared with CG, TG1 increased final body weight (p = 0.002) and average daily gain (ADG, p = 0.002), whereas TG2 did not differ from CG in either parameter. Both TG1 and TG2 decreased feed conversion ratio (FCR, p < 0.001), with TG1 showing a lower value than TG2. At day 60, TG1 had greater body oblique length than TG2 (p = 0.030), whereas neither TG1 nor TG2 differed from CG. Serum analysis: TG1 decreased ALT (p = 0.039) and increased CAT (p = 0.024) and HDL-C (p = 0.047) compared with CG, while TG2 did not differ from CG in these parameters. Both TG1 and TG2 decreased CRE compared with CG (p < 0.001). TG2 increased GSH-Px compared with CG and TG1 (p = 0.044), whereas TG1 did not differ from CG. Rumen fermentation: both TG1 and TG2 increased BCP compared with CG (p = 0.009); TG1 elevated isobutyrate compared with CG (p = 0.030), whereas TG2 did not differ from CG; TG2 reduced NH₃-N compared with CG (p = 0.026), whereas TG1 did not differ from CG. No α/β-diversity differences were observed, but taxa were modulated: TG1 enriched Actinobacteria and Olsenella; TG2 enriched Bacteroidetes, Prevotella, and Ruminococcus. Metabolomics: TG1 upregulated steroid hormone and phenylalanine metabolism; TG2 enhanced unsaturated fatty acid biosynthesis. Correlation networks linked Ruminococcus and UCG-005 to antioxidant status and VFA profiles. These findings indicate that different probiotic consortia are associated with distinct physiological outcomes in preweaning calves, supporting consortium selection for targeted feeding. Full article

Obesity and obesity-associated hepatic steatosis represent major metabolic health challenges, yet effective pharmacological interventions remain limited. Rosmarinic acid (RA), a natural polyphenol, has been reported to exert anti-obesity effects; however, its specific roles in restoring hepatic lipid homeostasis and modulating glucose metabolism under diet-induced obesity remain unclear. In this study, we investigated the metabolic effects and underlying mechanisms of RA in mice with high-fat diet (HFD)-induced obesity. RA significantly reduced body weight gain and adipose tissue mass without altering total energy intake, accompanied by increased nocturnal energy expenditure and fecal lipid excretion. RA restored hepatic lipid homeostasis by improving circulating lipid profiles and markedly attenuating hepatic steatosis, fibrosis, and hepatocellular injury. These effects were associated with increased fecal lipid excretion, suppression of hepatic lipogenesis, and enhancement of fatty acid oxidation-related markers. Furthermore, RA reduced fasting blood glucose levels and modulated the expression of hepatic glucose metabolism-related genes. Pancreatic immunohistochemistry showed morphological changes in insulin-positive and glucagon-positive cells following RA supplementation. Collectively, these findings indicate that RA ameliorates obesity-associated metabolic disturbances and hepatic steatosis through coordinated regulation of lipid metabolism and hepatic glucose metabolism-related pathways, highlighting its potential relevance for obesity-associated fatty liver conditions. Full article

The gut microbiota actively metabolizes steroid hormones, but the mechanisms of these transformations—particularly the sequence of enzymatic reactions and the source of hydrogen atoms—remain poorly understood. Conventional analytical approaches are hampered by the complex fecal matrix, isomeric metabolites, and the lack of authentic reference standards. Here we present a strategy based on parallel incubation of steroids with pooled human gut microbiota in H₂O and D₂O, followed by HPLC-HRMS, with the aim of determining the sequence of reductive steps and tracking the incorporation of atoms into steroid metabolites. Using a pooled fecal inoculum from multiple donors (n = 18) and three steroid substrates, we demonstrate that the characteristic mass shift (1.0063 Da per deuterium atom) enables detection of metabolites and distinguishes multi-step enzymatic reactions in the microbial community without recombinant enzymes and authentic standards. Progesterone and 19-hydroxy-4-androstene-3,17-dione underwent sequential two-step reduction incorporating up to three deuterium atoms, while 17α-hydroxypregnenolone followed a three-step pathway incorporating up to four deuterium atoms, consistent with localization to the A-ring. This workflow provides a practical tool for investigating gut microbial steroid metabolism in the context of human physiology and disease, with potential applications in monitoring microbial activity in endocrine disorders, inflammatory bowel disease, and neuropsychiatric conditions. Full article