Search Results (60)

Purpose: To investigate associations between lipid oxidation biomarkers (oxylipins), antioxidant micronutrients, lipoprotein particles, and apolipoproteins in multiple sclerosis (MS). Methods: Blood and neurological assessments were collected from 30 healthy controls, 68 relapsing remitting MS subjects, and 37 progressive MS subjects. Hydroxy (H) and hydroperoxy lipid peroxidation products of the polyunsaturated fatty acids (PUFAs) arachidonic (20:4, ω-6), linoleic (octadecadienoic acid or ODE, 18:2, ω-6), eicosapentaenoic (20:5, ω-3), and α-linolenic (18:3, ω-3) acids were measured using liquid chromatography–mass spectrometry. Antioxidant micronutrients, including β-cryptoxanthin and lutein/zeaxanthin, were quantified by high-performance liquid chromatography. Lipoprotein and metabolite profiles were obtained using nuclear magnetic resonance spectroscopy. Regression models were adjusted for age, sex, body mass index, and disease status. Results: The 9-hydroxy octadecadienoic acid to 13-hydroxy octadecadienoic acid ratio (9-HODE/13-HODE ratio), which reflects autoxidative versus enzymatic oxidation, was associated with MS status (p = 0.002) and disability on the Expanded Disability Status Scale (p = 0.004). Lutein/zeaxanthin (p = 0.023) and β-cryptoxanthin (p = 0.028) were negatively associated with the 9-HODE/13-HODE ratio. Apolipoprotein-CII, a marker of liver-X-receptor (LXR) signaling, was associated with 9-HODE/13-HODE ratio and other oxylipins. Octadecadienoic fatty acid-derived oxylipins were negatively associated with LC3A, a mitophagy marker, and positively correlated with 7-ketocholesterol, a cholesterol autoxidation product. Conclusions: Autoxidation of PUFAs is associated with greater disability in MS. Higher β-cryptoxanthin and lutein/zeaxanthin were associated with reduced auto-oxidation. Lipid peroxidation shows associations with LXR signaling, mitophagy, inflammation, and cholesterol autoxidation. Full article

Background: Heterosis (hybrid vigor) is a fundamental phenomenon in plant breeding, but its molecular basis remains poorly understood in perennial crops such as tea (Camellia sinensis). This study aimed to elucidate the molecular mechanisms underlying heterosis in tea and its hybrids by performing integrated transcriptomic and metabolomic analyses of F₁ hybrids derived from two elite cultivars, Fuding Dabaicha (FD) and Baojing Huangjincha 1 (HJC). Methods: Comprehensive RNA sequencing and widely targeted metabolomic profiling were conducted on the parental lines and F₁ hybrids at the one-bud-one-leaf stage. Primary metabolites (including amino acids, nucleotides, saccharides, and fatty acids) were quantified, and gene expression profiles were obtained. Transcriptomic and metabolomic datasets were integrated using KEGG pathway enrichment and co-expression network analysis to identify coordinated molecular changes underlying heterosis. Results: Metabolomic profiling detected 977 primary metabolites, many of which displayed non-additive accumulation patterns. Notably, linoleic acid derivatives (9(S)-HODE, 13(S)-HODE) and nucleotides (guanosine, uridine) exhibited significant positive mid-parent heterosis. Transcriptomic analysis revealed extensive non-additive gene expression in F₁ hybrids, and upregulated genes were enriched in fatty acid metabolism, nucleotide biosynthesis, and stress signaling pathways. Integrated analysis demonstrated strong coordination between differential gene expression and metabolite accumulation, especially in linoleic acid metabolism, cutin/suberine biosynthesis, and pyrimidine metabolism. Positive correlations between elevated fatty acid levels and transcript abundance of lipid metabolism genes suggest that the transcriptional remodeling of lipid pathways contributes to heterosis. Conclusions: These findings provide novel insights into tea plant heterosis and identify potential molecular targets for breeding high-quality cultivars. Full article

Fluoride is a widespread environmental toxin that disrupts metabolic and endocrine functions, but its impact on pancreatic inflammation and hormone secretion remains unclear. This study examined how chronic fluoride exposure affects pancreatic inflammation and secretory function in rats. Pregnant Wistar rats received sodium fluoride (NaF) at 50 mg/L in drinking water during gestation and lactation. Male offspring continued exposure until 3 months old. Controls received fluoride-free water. Pancreatic tissue and serum were collected. Fluoride levels were measured potentiometrically. Eicosanoids were quantified by SPE and HPLC. Serum insulin, glucagon, and somatostatin were measured by ELISA. Histological and biochemical markers of inflammation and oxidative stress were assessed. Fluoride exposure did not lead to significant accumulation in the pancreas or serum. However, fluoride-exposed rats exhibited a significant decrease in serum insulin and somatostatin concentrations, while glucagon levels remained unchanged. Additionally, the pancreas of fluoride-treated animals showed markedly elevated levels of pro-inflammatory eicosanoids, including prostaglandin E2, leukotrienes A4 and B4, and HETE/HODE derivatives, indicating activation of cyclooxygenase and lipoxygenase pathways. Sustained low-dose fluoride exposure induced pancreatic inflammation and disrupted endocrine homeostasis in rats. These findings suggest that chronic fluoride intake may impair insulin secretion and promote pre-diabetic alterations, warranting further research. Full article

Background: Pathological pregnancy is associated with various complications that may affect the health of both the mother and her offspring. In recent years, lipid metabolites such as hydroxyeicosatetraenoic (HETE) fatty acids and hydroxyoctadecadienoic (HODE) fatty acids have gained increasing interest as potential biomarkers of pathological processes in pregnancy. The aims of the present study were to investigate changes in HETE and HODE levels during pathological pregnancy and to assess their potential role in the development and monitoring of pregnancy complications. Attempts were made to determine associations in cross-sectional studies and relationships in longitudinal ones. Methods: In this study, a liquid chromatograph (HPLC) was used to separate the eicosanoids. The study group consisted of 72 Caucasian women, divided into a control group (n = 51) and a group with non-physiological pregnancy (n = 21). Results: The study results show that the levels of the tested metabolites of the cyclooxygenase (COX) and lipoxygenase (LOX) pathways increased as pregnancy progressed. Women with non-physiological courses of pregnancy who developed gestational diabetes and/or preeclampsia were characterized by dysregulation of the inflammatory signaling processes involving eicosanoids. Conclusions: Carbohydrate abnormalities during pregnancy were mainly associated with increased synthesis of 5-oxoETE and the use of 5-HETE in the control group but were not visible in the diabetic group. HODE acids probably do not play a significant role in pathological pregnancy. The relatively small size of the pathological group and the wide range of gestational age mean that the tests should be standardized and carried out on a larger scale. Full article

Ischemic stroke is a leading cause of mortality and disability in adults. The inflammatory cascade is driven by various inflammatory molecules, such as interleukin-1β (IL-1β), and counteracted by its antagonist, interleukin-1 receptor antagonist (IL-1Ra). Eicosanoids are inflammatory derivatives of free fatty acids. Arachidonic acid (AA) derivatives exhibit pro-inflammatory activity, while eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derivatives, known as specialized pro-resolving mediators, have anti-inflammatory properties. This study aimed to analyze potential associations between eicosanoids and key inflammatory molecules, including IL-1β and its antagonist IL-1Ra. In this prospective study, we investigated inflammatory molecules in 73 ischemic stroke patients. We analyzed interactions between IL-1β, IL-1Ra, and eicosanoids as follows: resolvin E1, prostaglandin E2, resolvin D1, lipoxin A4 (5S, 6R, 15R), protectin DX, maresin 1, leukotriene B4, 18RS-HEPE, 13S-HODE, 9S-HODE, 15S-HETE, 17 HDHA, 12S-HETE, 5-oxo-ETE, and 5-HETE. In 73 ischemic stroke patients, mean IL-1β was 1.31 ± 1.54 pg/mL and IL-1Ra 810.8 ± 691.0 pg/mL. Spearman correlations showed positive associations between IL-1β and protectin DX (ρ = 0.56, p < 0.001), and 17 HDHA (ρ = 0.26, p < 0.05) and 5-oxo-ETE (ρ = 0.27, p < 0.05). IL-1Ra correlated negatively with protectin DX (ρ = −0.58, p < 0.001) and 17 HDHA (ρ = −0.29, p < 0.05), and positively with leukotriene B4 (ρ = 0.34, p < 0.005). After multivariable adjustment, associations with IL-1β lost statistical significance, whereas the inverse relationships between IL-1Ra and protectin DX/17 HDHA remained significant (p < 0.005). Despite the known anti-inflammatory roles of protectin DX and 17 HDHA, and the pro-inflammatory role of leukotriene B4, their activity in the early subacute phase of ischemic stroke appears to be influenced by complex interplays, possibly mediated by IL-1β and IL-1Ra. The activity of protectin DX, 17 HDHA, and leukotriene B4 is correlated with IL-1β and IL-1Ra levels in the early subacute phase of stroke. Full article

Background: Adverse environmental conditions and an ever-increasing world population require devising and designing a roadmap for the next generation of wheat crops for high productivity and resilience to climate change. As such, a fundamental understanding of wheat metabolism and molecular descriptors of wheat seed potentials and quality is a sine qua non step. Objectives: In this study we investigated the seed metabolomes of five wheat cultivars to identify differential metabolic profiles and cultivar-related metabolic markers. Methods: Liquid chromatography-mass spectrometry (LC-MS) combined with computational strategies and functional analyses was applied. Metabolites were extracted using methanol, and samples were analysed on an LC-MS/MS system. Results: The results revealed that the extracted wheat cultivar seed metabolomes spanned a broad range of metabolite classes, including alkaloids, sugars, phenolics, amino acids, hormones, TCA compounds and lipids. Furthermore, the results also revealed key metabolic markers differentiating the wheat cultivars from one another, such as lipids (i.e., MGMG and 13-HODE) and flavonoids (i.e., rutin, tricin and vitexin), amongst many others. Conclusions: Such insights are important in assessing seed quality as well as in the selection of markers for seed nutrient and quality trait improvement in wheat breeding programmes. As such, this work generates novel actionable knowledge, a comprehensive metabolomic landscape of wheat seeds and potential markers for cultivar differentiation and quality assessment, which is essential for sustainable and improved wheat production. Thus, the study contributes towards the realisation of sustainable food security, an urgent call for action in a global partnership, as articulated in the United Nations Sustainable Development Goals, particularly zero hunger. Full article

Tropical forage crops vary widely in biochemical composition, resulting in inconsistent silage quality. Understanding how plant traits shape microbial and metabolic networks during ensiling is crucial for optimizing fermentation outcomes. Eight tropical forages—Sorghum bicolor (sweet sorghum), Sorghum × drummondii (sorghum–Sudangrass hybrid), Sorghum sudanense (Sudangrass), Pennisetum giganteum (giant Napier grass), Pennisetum purpureum cv. Purple (purple elephant grass), Pennisetum sinese (king grass), Leymus chinensis (sheep grass), and Zea mexicana (Mexican teosinte)—were ensiled under uniform conditions. Fermentation quality, bacterial and fungal communities (16S rRNA and ITS sequencing), and metabolite profiles (untargeted liquid chromatography–mass spectrometry, LC-MS) were analyzed after 60 days. Sweet sorghum and giant Napier grass showed optimal fermentation, with high lactic acid levels (111.2 g/kg and 99.4 g/kg, respectively), low NH₄⁺-N (2.4 g/kg and 3.1 g/kg), and dominant Lactiplantibacillus plantarum. In contrast, sheep grass and Mexican teosinte exhibited poor fermentation, with high NH₄⁺-N (6.7 and 6.1 g/kg) and Clostridium dominance. Fungal communities were dominated by Kazachstania humilis (>95%), while spoilage-associated genera such as Cladosporium, Fusarium, and Termitomyces proliferated in poorly fermented silages. Metabolomic analysis identified 15,827 features, with >3000 significantly differential metabolites between silages. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment revealed divergence in flavonoid biosynthesis, lipid metabolism, and amino acid pathways. In the sweet sorghum vs. sheep grass comparison, oxidative stress markers ((±) 9-HODE, Agrimonolide) were elevated in sheep grass, while sweet sorghum accumulated antioxidants like Vitamin D3. Giant Napier grass exhibited higher levels of antimicrobial flavonoids (e.g., Apigenin) than king grass, despite both being dominated by lactic acid bacteria. Sorghum–Sudangrass hybrid silage showed enrichment of lignan and flavonoid derivatives, while Mexican teosinte accumulated hormone-like compounds (Gibberellin A53, Pterostilbene), suggesting microbial dysbiosis. These findings indicate that silage fermentation outcomes are primarily driven by forage-intrinsic traits. A “forage–microbiota–metabolite” framework was proposed to explain how plant-specific properties regulate microbial assembly and metabolic output. These insights can guide forage selection and development of precision inoculant for high-quality tropical silage. Full article

Background: Post-production storage plays a pivotal role in developing the characteristic flavor profile of Baijiu, a traditional alcoholic beverage in China. While aging markers remain crucial for quality authentication, the identification of reliable metabolic indicators for chronological determination requires further exploration. Methods: This study establishes a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) methodology for quantifying five linoleic acid-derived oxidative metabolites in Baijiu: 9,12,13-trihydroxy-10(E)-octadecenoic acid (9,12,13-TriHOME), 9,10-Dihydroxy-12-octadecenoic acid (9,10-DiHOME), 9-oxo-(10E,12Z)-octadecadienoic acid (9-OxoODE), 9-hydroxy-(10E,12Z)-octadecadienoic acid (9-HODE) and 13-hydroxyoctadeca-(9Z,11E)-octadecadienoic acid (13-HODE). Results: The optimized protocol demonstrated exceptional sensitivity with limits of detection at 0.4 ppb through membrane-filtered direct dilution. Calibration curves exhibited excellent linearity (R² > 0.9990) across 1.0–100.0 ppb ranges. Method validation revealed satisfactory recovery rates (87.25–119.44%) at three spiking levels (10/20/50 ppb) with precision below 6.96% RSD. Application to authentic samples showed distinct temporal accumulation patterns. Light-aroma Baijiu exhibited storage duration-dependent increases in all five oxides. Strong aroma variants demonstrated significant positive correlations for 9,12,13-TriHOME, 9,10-DiHOME, and 9-OxoODE with aging time. Conclusions: These findings systematically characterize linoleic acid oxidation products as potential aging markers, providing both methodological advancements and new insights into Baijiu aging mechanisms. Full article

Background/Objectives: Irritable bowel syndrome (IBS) is a complex disorder affecting 10% of the global population, but the underlying mechanisms remain poorly understood. By integrating multifluid metabolomics, we aimed to identify metabolite markers of IBS in a large population-based cohort. Methods: We included individuals from TwinsUK with and without IBS, ascertained using the Rome III criteria, and analysed serum (232 cases, 1707 controls), urine (185 cases, 1341 controls), and stool (186 cases, 1284 controls) metabolites (Metabolon Inc.). Results: After adjusting for covariates, and multiple testing, 44 unique metabolites (25 novel) were associated with IBS, including lipids, amino acids, and xenobiotics. Androsterone sulphate, a sulfated steroid hormone precursor, was associated with lower odds of IBS in both urine (0.69 [95% confidence interval = 0.56–0.85], p = 2.34 × 10⁻⁴) and serum (0.75 [0.63–0.90], p = 1.54 × 10⁻³. Moreover, suberate (C8-DC) was associated with higher odds of IBS in serum (1.36 [1.15–1.61]; p = 1.84 × 10⁻⁴) and lower odds of IBS in stool (0.76 [0.63–0.91]; p = 2.30 × 10⁻³). On the contrary, 32 metabolites appeared to be fluid-specific, including indole, 13-HODE + 9-HODE, pterin, bilirubin (E,Z or Z,Z), and urolithin. The remaining 10 metabolites were associated with IBS in one fluid with suggestive evidence (p < 0.05) in another fluid. Finally, we identified androgenic signalling, dicarboxylates, haemoglobin, and porphyrin metabolism to be significantly over-represented in individuals with IBS compared to controls. Conclusions: Our results highlight the utility of a multi-fluid approach in IBS research, revealing distinct metabolic signatures across biofluids. Full article

To understand the impact and mechanism of removing fat and skin tissue on the nutritional metabolism of Chinese dry cured ham, the differential metabolites (DMs) profile between lean ham (LH) and fatty ham (FH) was explored though untargeted metabolomics based on UPLC-MS/MS. The results showed significant differences of the metabolite profiles between FH and LH. A total of 450 defined metabolites were detected, and 266 metabolites among them had significantly different abundances between the two hams, mainly including organic acids and derivatives, and lipids and lipid-like molecules, as well as organoheterocyclic compounds. Furthermore, 131 metabolites were identified as DMs, among which 101 and 30 DMs showed remarkably higher contents in FH and LH, respectively. The further Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that DMs can be mostly enriched in the pathways of ABC transporters, amino acid biosynthesis, protein digestion and absorption, aminoacyl-tRNA biosynthesis, and 2-oxocarboxylic acid metabolism. Moreover, the metabolic network of DMs revealed that the prominent DMs in FH, such as 9(S)-HODE, 9,10-EpOME, 13-Oxo-ODE, L-palmitoyl carnitine, and D-fructose, were primarily involved in the endogenous oxidation and degradation of fat and glycogen. Nevertheless, the dominant DMs in LH, such as 2-isopropylmalic acid, indolelactic acid, and hydroxyisocaproic acid, were mainly the microbial metabolites of amino acids and derivates. These findings could help us understand how fat-deficiency affects the nutritional metabolism of Chinese dry-cured hams from a metabolic perspective. Full article

Background: Cytochrome P450 2B6 (CYP2B6) is a sexually dimorphic, anti-obesity CYP enzyme responsible for the metabolism of xeno- and endobiotics, including the metabolism of polyunsaturated fatty acids (PUFAs) into 9-hydroxyoctadecadienoic acid (9-HODE) and 9-hydroxyoctadecatrienoic acid (9-HOTrE). However, humanized CYP2B6 transgenic (hCYP2B6-Tg) mice are sensitive to diet-induced hepatic steatosis despite their resistance to obesity. The purpose of this study was to determine if 9-HODE, 9-HOTrE, or other factors contribute to the sexually dimorphic steatosis observed in hCYP2B6-Tg mice. Results: Cyp2b9/10/13-null (Cyp2b-null) mice were injected with either 9-HODE or 9-HOTrE for 2 days and were then subjected to a fasting period of 20 h to induce steatosis. Serum lipids were moderately increased, especially in females, after 9-HODE (triglycerides (TGs), very low-density lipoproteins (VLDLs)) and 9-HOTrE (high-density lipoproteins (HDLs), low-density lipoproteins (LDLs), cholesterol) treatment. No change in hepatic lipids and few changes in hepatic gene expression were observed in mice treated with either oxylipin, suggesting that these oxylipins had minimal to moderate effects. Therefore, to further investigate CYP2B6’s role in steatosis, hCYP2B6-Tg and Cyp2b-null mice were subjected to a 20 h fast and compared. Both male and female hCYP2B6-Tg mice exhibited increased steatosis compared to Cyp2b-null mice. Serum cholesterol, triglycerides, HDLs, and VLDLs were increased in hCYP2B6-Tg males. Serum triglycerides and VLDLs were decreased in hCYP2B6-Tg females, suggesting the greater hepatic retention of lipids in females. Hepatic oxylipin profiles revealed eight perturbed oxylipins in female hCYP2B6-Tg mice and only one in males when compared to Cyp2b-null mice. RNA-seq also demonstrated greater effects in females in terms of the number of genes and gene ontology (GO) terms perturbed. There were only a few overlapping GO terms between sexes, and lipid metabolic processes were enriched in hCYP2B6-Tg male mice but were repressed in hCYP2B6-Tg females compared to Cyp2b-nulls. Conclusions: hCYP2B6-Tg mice are sensitive to fasting-mediated steatosis in males and females, although the responses are different. In addition, the oxylipins 9-HODE and 9-HOTrE are unlikely to be the primary cause of CYP2B6’s pro-steatotic effects. Full article

Flash column chromatographic fractionation of tree of heaven (Ailanthus altissima) stem and trunk bark extracts, guided by thin-layer chromatography (TLC)–Bacillus subtilis assay and TLC–heated electrospray high-resolution tandem mass spectrometry (HESI-HRMS/MS), lead to the isolation of six known compounds: (9Z,11E)-13-hydroxy-9,11-octadecadienoic acid (13-HODE, A1), (10E,12Z)-9-hydroxy-10,12-octadecadienoic acid (9-HODE, A2), hexadecanedioic acid (thapsic acid, A3), 16-hydroxyhexadecanoic acid (juniperic acid, A4), 16-feruloyloxypalmitic acid (alpinagalanate, A5), and canthin-6-one (A6). Their structures were elucidated by HESI-HRMS/MS and one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. This is the first study identifying A1–A5 in A. altissima tree. Except for A5, all isolated compounds exhibited antibacterial activity against B. subtilis in microdilution assays. A6 showed the strongest effect with a minimum inhibitory concentration (MIC) value of 8.3 µg/mL. The antibacterial activity of A3 and A4 is newly described. Full article

Purpose: To investigate the causal relationship between type 1 diabetes (T1D) and cataracts and to explore the mediating role of serum metabolites. Methods: This study employed bidirectional Mendelian randomization (MR) using genetic variants as instrumental variables to infer causality in both directions: from T1D to cataracts and cataracts to T1D. Genetic data for T1D, its complications, and cataracts were sourced from independent genome-wide association study (GWAS) datasets. A two-step multivariable MR combined with mediation analysis was conducted to evaluate the indirect effects of serum metabolites in the causal pathway from T1D to cataracts. Results: The MR analysis demonstrated a significant causal association between T1D and an increased risk of cataracts (OR = 1.01–1.05; p < 0.05). Further analysis showed that patients with T1D complications such as coma, ketoacidosis, nephropathy, and retinopathy exhibited a significantly higher risk of developing cataracts compared to those without complications. Sensitivity analyses upheld the robustness of these findings, with no evidence of heterogeneity or pleiotropy. Additionally, 102 serum metabolites were found to exhibit statistically significant mediation effects on cataract risk, with four (13-HODE + 9-HODE, 2-naphthol sulfate, docosadienoate (22:2n6), and X-12906) showing significant mediation effects. Specifically, 13-HODE + 9-HODE had a protective effect, while the other three metabolites were linked to an increased cataract risk. Conclusions: This study provides strong evidence of a causal link between T1D and cataracts, highlighting the mediating role of specific serum metabolites. These findings underscore the importance of early detection and management of cataracts in patients with T1D and suggest potential therapeutic targets for mitigating cataract risk. Further research should focus on replicating these findings in diverse populations and exploring the underlying metabolic pathways in greater detail. Full article

Aspergillus fumigatus can cause invasive pulmonary aspergillosis (IPA). Fungicidal azoles and fungistatic caspofungin (CAS) are the first- and second-line therapies, respectively, used to treat IPA. Treatment of A. fumigatus with CAS or micafungin induces the production of the oxylipin 5,8-diHODE by the fungal oxygenase PpoA. For this article, we investigated the influence of ppo genes, which encode the fatty acid oxygenases responsible for oxylipin biosynthesis, on CAS tolerance. The influence of PpoA and PpoC on CAS tolerance is mediated by MpkA phosphorylation and protein kinase A (PKA) activity. RNAseq transcriptional profiling and the label-free quantitative proteomics of the ppoA and ppoC mutants showed that differentially expressed genes and proteins are related to secondary metabolites and carbohydrate metabolism. We also characterized two clinical isolates, CM7555 and IFM61407, which decrease and increase susceptibility to CAS, respectively. CM7555 does not exhibit increased oxylipin production in the presence of CAS but oxylipin induction upon CAS exposure is increased in IFM61407, suggesting that oxylipins are not the only mechanism involved in CAS tolerance in these isolates. Upon CAS exposure, CM7555 has higher MpkA phosphorylation and PKA activity than IFM61407. Our results reveal the different aspects and genetic determinants involved in A. fumigatus CAS tolerance. Full article

Oxidative stress is a major factor that limits the development of the poultry industry. Ferulic acid (FA) has an antioxidant effect in birds, but the mechanism is not fully understood. In this study, we stimulated oxidative stress in 28-day-old female Linwu ducks by lipopolysaccharide (LPS) and fed them a diet supplemented with FA for 28 days. Results showed that FA alleviated LPS-induced growth performance regression, oxidative stress, and microbiota imbalance in ducks. An integrated metagenomics and metabolomics analysis revealed that s_Blautia_obeum, s_Faecalibacterium_prausnitzii, s_gemmiger_formicilis, and s_Ruminococcaceae_bacterium could be the biomarkers in the antioxidant effect of FA, which interacted with dihydro-3-coumaric acid, L-phenylalanine, and 13(S)-HODE, and regulated the phenylalanine metabolism and PPAR signaling pathway. This study revealed the mechanism of the antioxidant effect of FA, which provided evidence of applying FA as a new antioxidant in commercial duck production. Full article