Multi-omics and functional validation reveal that Methanobrevibacter-derived L-3-aminoisobutyrate alleviates subclinical mastitis in dairy goats via the HSPA1B-p65 signaling pathway.
This study identifies BAIBA as a microbiota-derived metabolite that protects against SCM by restraining mammary inflammation via the HSPA1B-NF-κB axis, establishing a mechanistic gut-mammary link and highlighting a potential non-antibiotic intervention strategy.
Abstract
Background
Subclinical mastitis (SCM) is prevalent in dairy livestock and compromises milk quality and lactation performance. Although often attributed to bacterial infection, many cases lack identifiable pathogens, suggesting alternative mechanisms. While evidence supports a gut-mammary gland axis, the microbial drivers and microbiota-derived metabolites linking gut dysbiosis to SCM remain unclear. Here, we aimed to identify SCM-associated gut microbial markers, prioritize candidate therapeutic metabolites and define the underlying mechanism.
Results
Based on differences in somatic cell count (SCC) and inflammatory phenotypes across a cohort of 167 mid-lactation Saanen dairy goats, we selected 6 healthy and 6 SCM goats for downstream analyses. By integrating metagenomics, metabolomics, cross-species fecal microbiota transplantation (FMT) and functional validation in vitro and in vivo, we found that SCM was accompanied by reduced milk yield and heightened inflammatory signatures. Compared with the Healthy group, SCM goats exhibited marked remodelling of the gut microbiota, with enrichment of opportunistic taxa (Eubacterium and Blautia) and a pronounced depletion of archaeal Methanobrevibacter spp. Notably, FMT from SCM donors recapitulated mammary inflammatory phenotypes in mice, supporting a causal contribution of gut dysbiosis to mammary inflammation. Joint metagenomic functional profiling and metabolomics further identified the branched-chain amino-acid-derived metabolite L-3-aminoisobutyrate (BAIBA) as significantly enriched in the gut of healthy goats. Moreover, Methanobrevibacter spp. harboured key enzyme genes (vorA, vorB and vorD) implicated in BAIBA biosynthesis. In an LPS-challenged MAC-T model, BAIBA attenuated mammary epithelial inflammation by activating endoplasmic reticulum protein quality control programmes and restoring HSPA1B expression, thereby suppressing NF-κB activation and reducing pro-inflammatory cytokine production. Finally, in naturally infected goats, intramammary administration of BAIBA lowered SCC, highlighting translational potential.
Conclusions
This study identifies BAIBA as a microbiota-derived metabolite that protects against SCM by restraining mammary inflammation via the HSPA1B-NF-κB axis, establishing a mechanistic gut-mammary link and highlighting a potential non-antibiotic intervention strategy. Video Abstract.
ABSTRACT Flatulence is closely associated with gut dysbiosis, yet the characteristic microbial signatures, metabolic alterations, and actionable intervention targets remain unclear. This limited mechanistic understanding has hindered the development of precise microbiota-based strategies for managing flatulence. Here, we found that participants with flatulence exhibited marked shifts in gut microbial functions and fecal metabolic profiles compared with healthy controls, characterized by enhanced abnormal fermentation, enrichment of oxidative stress-related functions, elevated low-grade inflammatory signatures, and reduced anti-inflammatory and mucosal-protective metabolic features. Faecalibacterium prausnitzii was significantly negatively associated with the high-gas-producing phenotype. In vitro replenishment experiments further validated the role of F. prausnitzii in reducing gas production, promoting butyrate generation, and remodeling butyrate-associated microbial communities. Based on microbial interaction analysis, we identified Bifidobacterium longum CCFM1319 as a candidate strain for targeting F. prausnitzii. In a double-blind, randomized, placebo-controlled clinical trial, supplementation with B. longum CCFM1319 significantly increased intestinal F. prausnitzii abundance and improved flatulence-related symptoms. Collectively, these findings reveal the microbiota and metabolic dysbiosis underlying flatulence, highlight the key regulatory role of F. prausnitzii, and lays the foundation for targeted microbiota-based intervention strategies for flatulence.
Rui-Min Chen, Chuan Zhang, Shi-Kai Yan et al.· Gut microbes· 0 citations
This study evaluated the effects of dietary SYNSEA Premium postbiotics on growth, immunity, disease resistance, intestinal microbiota, and host metabolism in Asian seabass (Lates calcarifer). Fish were fed a control diet or diets supplemented with heat-killed Lactiplantibacillus plantarum LP28, L. plantarum LP1008, and Bacillus subtilis at 108 (LSP) or 109 (HSP) cells kg−1 diet for 56 days. Postbiotic supplementation did not significantly affect growth performance, feed efficiency, production, condition factor, or dorsal muscle composition, but significantly improved survival. Fish receiving postbiotics also exhibited higher survival following Vibrio alginolyticus and iridovirus challenges. These protective effects were accompanied by enhanced superoxide dismutase, phagocytic, and lysozyme activities and modulation of immune-related genes, including tgf-β1, tnf, ifn-γ1, c3, and mx. Exploratory microbiome and metabolome analyses, which were restricted to the control and LSP groups, identified differences in the relative abundance of specific intestinal microbial taxa and associations between microbial composition and host metabolic profiles. The LSP group showed lower relative abundances of potential pathogens such as Salmonella enterica, Lactococcus garvieae, and Staphylococcus warneri, although the overall microbial community structure did not differ significantly between groups. Metabolomic analysis of the LSP group further showed changes in D-glucose, pentose phosphate pathway intermediates, reduced glutathione, CoA, and 2-methylacetoacetyl-CoA relative to the control. Collectively, SYNSEA Premium improved survival, immune responses, and resistance to bacterial and viral infections without significantly affecting growth performance, while exploratory omics analysis of the LSP treatment identified associated microbial and metabolic changes.
Metabolic dysfunction‐associated steatotic liver disease (MASLD) is a prevalent metabolic disorder linked to gut–liver axis dysregulation. Dietary interventions targeting gut microbiota and host metabolism are promising, yet the effects of specific bioactive components remain unclear. Conjugated linoleic acid (CLA), a functional fatty acid in dairy, may regulate lipid metabolism and inflammation, but its clinical efficacy and mechanisms in MASLD are not well defined. This study evaluated CLA‐enriched fermented dairy using a multi‐omics and causal modeling framework. In a 120‐day randomized controlled trial, 60 MASLD patients consumed CLA‐enriched fermented dairy or standard yogurt. Fecal samples underwent 16S rRNA sequencing, and serum samples were analyzed by untargeted liquid chromatography–mass spectrometry (LC–MS) metabolomics. Liver function and metabolic markers were assessed before and after the intervention. Causal mediation analyses explored mechanistic links among the intervention, microbiota, metabolites, and clinical outcomes. The intervention group showed significant reductions in serum alanine aminotransferase (ALT), total cholesterol (TC), creatinine, and high‐sensitivity C‐reactive protein (hs‐CRP). Gut microbiota shifts included increased
Bacteroides
,
Blautia
, and
Fusicatenibacter
and decreased
Enterococcus
and
Sutterella
. Metabolomics revealed upregulated energy pathways and negative associations between liver enzymes, phosphatidylcholines, and acylcarnitines. Causal mediation identified key microbial (e.g.,
Lachnospiraceae
UCG‐008) and metabolic (e.g., 5‐Benzylacyclouridine and vaccenic acid) mediators linking the intervention to clinical improvements. CLA‐enriched fermented dairy beneficially modulates gut microbiota and host metabolism, improving liver and systemic metabolic health in MASLD patients. The study highlights CLA's therapeutic potential and demonstrates the value of multi‐omics and causal inference to elucidate diet–host interactions.
Late lactation is frequently accompanied by changes in goat milk composition and volatile-related quality, which may reduce its commercial value. This study investigated whether Astragalus polysaccharide (APS), a plant-derived bioactive polysaccharide from Astragalus membranaceus (Fisch.) Bunge, is associated with milk quality responses distinct from those induced by probiotic supplementation. Late lactation Saanen dairy goats were assigned to probiotic or APS supplementation for 30 days, and milk samples were analyzed using conventional composition testing, electronic nose (E-nose) profiling, proteomics, untargeted metabolomics, and lipidomics. APS supplementation reduced milk urea nitrogen by 6.20 mg/dL and decreased milk fat percentage, while electronic nose (E-nose) profiling revealed a distinct sensor-level volatile fingerprint dominated by W5S, W2W, and W1S responses. At the molecular level, APS generated a broader metabolomic response than probiotic supplementation, with 904 versus 587 differential metabolites, and was associated with a milk proteomic signature featuring higher ATP citrate lyase abundance (2.52-fold). Lipidomics further showed selective remodeling of milk lipid subclasses, including increased phosphatidylethanolamine, phosphatidylcholine, and ceramide abundance by approximately 1.4-fold, 1.5-fold, and nearly 5-fold, respectively. Together, these milk-based data indicate that APS supplementation was associated with a distinct quality signature involving nitrogen-use indicators, volatile-related sensor profiles, lipid-related protein features, and lipid subclass redistribution. The findings support APS as a potential non-microbial nutritional strategy for modulating late lactation goat milk quality.
Shan-Shan Han, Peng Wang, Yun-Hong Hu et al.· Food Chemistry: X· 0 citations
The gut microbiome is increasingly recognised as a modifiable contributor to metabolic, immune, and stress-related physiology, yet many nutritional interventions produce broad microbial shifts that may be poorly tolerated. We investigated the effects of a fermented and pasteurised oat-based preparation (Keystone) on microbiome composition and selected biomarkers in a 4-week randomised, double-blind, placebo-controlled trial in generally healthy adults. Seventy-six participants completed the intervention (38 placebo, 38 Keystone). Stool samples collected at baseline and week 4 underwent shotgun metagenomic sequencing, and serum butyrate, IL-8, morning cortisol, albumin/globulin ratio, routine clinical chemistries, DASS-21, and SF-36 were assessed. The intervention did not affect alpha or beta diversity. In contrast, species-level analysis showed a distinct compositional signature, with enrichment of taxa including Akkermansia spp., Bacteroides intestinalis, Bifidobacterium pseudocatenulatum, and Anaerostipes caccae in the Keystone group, alongside lower abundance of several Haemophilus, Megasphaera, and Prevotella taxa relative to placebo (FDR < 0.001). Nominally significant baseline-by-treatment interactions were observed for morning cortisol ( P = 0.03), IL-8 ( P = 0.04), and albumin/globulin ratio ( P = 0.03), while serum butyrate showed a near-significant trend ( P = 0.053). SF-36 emotional well-being improved within the Keystone group. No adverse events were reported. These results indicate that Keystone was safe and well tolerated and selectively modulates the gut microbiome, with exploratory associations for host stress and inflammatory markers that offer key insights for future follow-up studies. Trial registration: The trial was IRB approved and registered with ClinicalTrials.gov NCT07527286.
C. J. Delebecque, M. La Monica, D. Keller et al.· Beneficial Microbes· 0 citations
Background: Current understanding of the biotransformation of bioactive compounds in Portulaca oleracea through probiotic fermentation remains limited, and the anti-diarrheal mechanisms of the resulting fermented products have yet to be fully elucidated. Methods: In this exploratory study, we employed untargeted metabolomics together with a senna-induced acute diarrhea mouse model to investigate P. oleracea co-fermented with Lactiplantibacillus plantarum and Bacillus subtilis. Results: Metabolomic profiling identified 220 metabolites significantly altered by fermentation, predominantly comprising increased levels of lipids, phenylpropanoids, and polyketides. Compared with the unfermented P. oleracea control, fermented P. oleracea (FP) effectively reduced the diarrhea index, lowered serum levels of inflammatory cytokines (IL-1β, IL-6, TNF-α) and neurotransmitters (5-HT, substance P), and restored Na+/K+ balance as well as ileal histomorphology. Transcriptomic analysis and RT-qPCR validation further demonstrated that FP modulated the expression of genes involved in focal adhesion, PI3K-Akt, cGMP-PKG, and mineral absorption pathways. Conclusions: Fermented P. oleracea (FP) alleviates acute diarrhea through multi-target mechanisms. Notably, fermentation endows P. oleracea with markedly superior intestinal protective effects relative to the unfermented counterpart. These findings provide preliminary experimental evidence supporting the potential of fermented P. oleracea as a candidate for intestinal protective functional food research.
Rui Chen, Chun-Nan Yan, Xiyu Li et al.· Nutrients· 0 citations
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