In the dam discharge season, the supersaturation of total dissolved gas (TDG) in the downstream channel can seriously affect the survival of aquatic organisms. However, few studies have revealed the mechanism by which TDG supersaturation affects the physiology of fish thus far. The present study was conducted to study the mechanism of the effect of TDG supersaturation on Schizothorax davidi, a species that is very sensitive to gas bubble disease. S. davidi was exposed to 116 % TDG supersaturation stress for 24 h. Serum biochemical tests showed that the aspartate aminotransferase and alanine aminotransferase levels after TDG supersaturation exposure were significantly decreased compared to those in the control group, while superoxide dismutase activity was significantly increased. RNA-Seq of gill tissues identified 1890 differentially expressed genes (DEGs), which consisted of 862 upregulated genes and 1028 downregulated genes, in the TDG supersaturation group vs. the control group. Pathway enrichment analysis revealed that the cell cycle, apoptosis and immune signaling pathways were affected by TDG stress. The results of this study may contribute to our understanding of the underlying molecular mechanism of environmental stress in fish.

在大坝泄洪季节，下游河道总溶解气体（TDG）过饱和会严重影响水生生物的生存。然而，迄今为止很少有研究揭示TDG过饱和度影响鱼类生理的机制。本研究旨在研究 TDG 过饱和度对裂腹鱼（一种对气泡病非常敏感的物种）的影响机制。S. davidi暴露于 116% TDG 过饱和应力 24 小时。血清生化检查显示天冬氨酸氨基转移酶和丙氨酸与对照组相比，TDG过饱和暴露后转氨酶水平显着降低，而超氧化物歧化酶活性显着升高。鳃组织的 RNA-Seq 在 TDG 过饱和组与对照组中鉴定出 1890 个差异表达基因 (DEG)，其中包括 862 个上调基因和 1028 个下调基因。Pathway富集分析显示细胞周期、细胞凋亡和免疫信号通路受TDG应激影响。这项研究的结果可能有助于我们理解鱼类环境胁迫的潜在分子机制。