Abstract
Hydrogen peroxide (H(2)O(2)), a ubiquitous reactive oxygen species in aquatic ecosystems, has been shown to induce toxicological effects in aquatic animals. However, the molecular mechanisms underlying H(2)O(2)-mediated alterations in muscle quality and metabolic homeostasis remain largely unexplored. In this study, we performed integrated metabolomic and transcriptomic analyses to characterize the molecular mechanisms underlying H(2)O(2)-induced oxidative stress in fish muscle tissue. Common carp (Cyprinus carpio) were randomized into two groups: a control group (0.0 mM H(2)O(2)) and an H(2)O(2)-treated group (1.0 mM H(2)O(2)) for a 14-day exposure. Following the exposure, comprehensive analyses, including fatty acid composition, amino acid profiles, and multi-omics sequencing, were conducted to elucidate the metabolic responses to oxidative stress. The results showed neither the amino acid nor the fatty acid composition exhibited significant modifications following H(2)O(2) exposure. Metabolomic profiling identified 83 upregulated and 89 downregulated metabolites, predominantly comprising organic acids and derivatives, lipids and lipid-like molecules. These differential metabolites were associated with histidine and purine-derived alkaloid biosynthesis, glyoxylate and dicarboxylate metabolism pathways. Transcriptomic analysis identified 470 upregulated and 451 downregulated differentially expressed genes (DEGs). GO enrichment analysis revealed that these DEGs were significantly enriched in muscle tissue development and transcriptional regulatory activity. KEGG analysis revealed significant enrichment in oxidative phosphorylation, adipocytokine signaling, and PPAR signaling pathways. The elevated oxidative phosphorylation activity and upregulated adipocytokine/PPAR signaling pathways collectively indicate H(2)O(2)-induced metabolic dysregulation in carp muscle. Through the integration of metabolomics and transcriptomics, this study offers novel insights into the toxicity of H(2)O(2) in aquatic environments, elucidates adaptive mechanisms of farmed fish to oxidative stress, and provides a theoretical basis for developing antioxidant strategies.