Nervonic acid ameliorates high-fat diet-induced obesity and is associated with gut microbiota, fecal metabolic remodeling, and short-chain fatty acid profiles

Background Nervonic acid (NA) is a bioactive long-chain monounsaturated fatty acid with pivotal metabolic regulatory functions; nevertheless, its underlying mechanisms against high-fat diet-induced obesity remain poorly elucidated. This study adopted a fecal metabolomics strategy to systematically investigate the modulatory effects of NA supplementation on gut microbial composition and fecal metabolic signatures in high-fat diet (HFD)-induced obese mice. Methods Male C57BL/6 mice were subjected to HFD feeding and continuous intervention with gradient doses of NA for 12 weeks. Fecal samples were collected for untargeted metabolomic profiling via ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), while gas chromatography-tandem mass spectrometry (GC-MS/MS) was applied for quantitative detection of targeted short-chain fatty acids (SCFAs). Combined with previously reported 16S rRNA gene sequencing datasets, we further comprehensively analyzed the influences of NA on gut microbiota community structure, fecal metabolic profiles, and microbe-metabolite correlation networks. Results UHPLC-MS/MS metabolomic analysis demonstrated that NA intervention remarkably reshaped the overall fecal metabolic landscape of obese mice. Differential metabolite screening showed that NA supplementation restored the abnormal depletion of hypoxanthine and uracil, significantly reduced the abundance of arachidonic acid (AA), and markedly elevated the levels of stearidonic acid (SDA), malic acid, citric acid, and phosphatidylcholine PC(18:0_18:2). Functional enrichment analysis indicated that these altered metabolites were predominantly enriched in pyrimidine metabolism, glycine/serine/threonine metabolism, α-linolenic acid metabolism, linoleic acid metabolism, and tricarboxylic acid (TCA) cycle pathways. GC-MS/MS quantification further verified that NA treatment significantly increased fecal contents of acetic acid, propionic acid, butyric acid, and caproic acid in HFD-induced obese mice. Spearman correlation analysis revealed that NA-mediated metabolic remodeling was closely correlated with the modulation of inflammation-associated bacterial genera ( norank_Desulfovibrionaceae , Mucispirillum , and Alistipes ) and potential beneficial gut microbes ( norank_Rikenellaceae ). Conclusions NA intervention ameliorated HFD-induced obesity-associated metabolic disorders and was accompanied by remodeling of fecal metabolic profiles and alterations in gut microbial structure. This study deepens the mechanistic understanding of NA in alleviating high-fat diet-triggered gut dysbiosis and metabolic perturbation and provides novel insights into the gut microbiota-dependent regulatory mechanism of NA against obesity, laying a theoretical foundation for the application of NA in obesity metabolic intervention.