Study on the High-Temperature Adaptation Mechanisms of Triploid Rainbow Trout at Different Specifications Based on Transcriptome and Metabolome Analysis

This study elucidates the molecular and metabolic mechanisms underlying high-temperature adaptation in triploid rainbow trout (Oncorhynchus mykiss) through integrated transcriptomic and metabolomic analyses. Liver tissues from summer (high-temperature) and autumn (low-temperature) cohorts were subjected to RNA sequencing and LC-MS/MS profiling, revealing significant temperature-driven perturbations. Transcriptome analysis identified widespread downregulation of genes under summer heat stress, particularly in pathways linked to amino acid metabolism (e.g., glutamine synthesis), oxidative phosphorylation, and ribosomal function. Metabolomic profiling demonstrated pronounced shifts in lipid metabolism (e.g., sphingolipids, glycerophospholipids) and organic acid derivatives, indicative of disrupted energy homeostasis and membrane stability. Integrated multi-omics analysis highlighted the pentose phosphate pathway as a shared regulatory node, with strong correlations observed between key genes (HMGCR, CS) and metabolites (cholesterol, citric acid). Negative associations linked urate oxidase (UOX) and acetylcholinesterase (ACHE) to uric acid and acetylcholine dynamics, respectively. Mechanistically, summer heat stress impaired mitochondrial energy production, exacerbated oxidative damage, and triggered lipid peroxidation, collectively constraining growth and survival. These findings advance precision aquaculture strategies by identifying molecular targets (e.g., oxidative phosphorylation genes, lipid synthesis regulators) for enhancing thermal resilience. The study provides actionable insights into mitigating climate-driven challenges in cold-water fisheries, aligning with sustainable aquaculture development goals.