Ammonia is toxic to most bony fishes. However, little information is available on the toxicology mechanisms induced by ammonia and the means to mitigate the effects by various fishes. In this study, four groups of experiments were designed and carried out to test the response of dolly varden char to ammonia toxicity and their mitigation through methionine sulfoximine (MSO). NaCl group was injected with NaCl, NH3 group was injected with ammonium acetate, NH3+MSO group was injected with ammonium acetate and MSO, MSO group was injected with MSO. Results showed that ammonia toxicity could lead to blood deterioration (elevation in white blood cell and blood ammonia), free amino acid imbalance (elevation in glutamine, glutamate, arginine and ornithine, coupled with reduction of citrulline and aspartate), ammonia metabolism enzyme activity inhibition (reduction in carbamyl phosphate synthetase, ornithine transcarbamylase and arginase), oxidative stress (reduction in superoxide dismutase, catalase and glutathione peroxidase) and immunosuppression (reduction in lysozyme, 50% hemolytic complement, total immunoglobulin and phagocytic index), but the MSO can eliminate fatal effect of oxidative damage. In addition, ammonia poisoning could induce down-regulation of antioxidant enzymes coding genes (SOD, CAT and GPx) and up-regulation of inflammatory cytokine genes (TNFα, IL-1β and IL-8) transcription, suggesting that immunosuppression and inflammation may relate to oxidative stress in fish.

中文翻译：

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多莉瓦尔登炭（Salvelinus malma）的急性氨中毒和蛋氨酸亚砜肟的作用。

氨对大多数骨鱼类有毒。但是，关于氨引起的毒理学机理以及减轻各种鱼类的影响的手段的信息很少。在这项研究中，设计并进行了四组实验，以测试多莉瓦尔登炭对氨中毒的反应以及通过蛋氨酸硫代肟（MSO）缓解它们的反应。NaCl组注射NaCl，NH3组注射乙酸铵，NH3 + MSO组注射乙酸铵和MSO，MSO组注射MSO。结果表明，氨中毒会导致血液恶化（白细胞和血氨升高），游离氨基酸失衡（谷氨酰胺，谷氨酸，精氨酸和鸟氨酸升高，以及瓜氨酸和天冬氨酸减少），抑制氨代谢酶活性（减少氨基甲酸酯磷酸合成酶，鸟氨酸转氨甲酰酶和精氨酸酶），氧化应激（减少超氧化物歧化酶，过氧化氢酶和谷胱甘肽过氧化物酶）和免疫抑制（减少溶菌酶，50％溶血补体，总免疫球蛋白和吞噬指数）但是MSO可以消除氧化损伤的致命影响。此外，氨中毒可能会诱导抗氧化酶编码基因（SOD，CAT和GPx）下调，而炎症细胞因子基因（TNFα，IL-1β和IL-8）的转录上调，表明免疫抑制与炎症可能有关对鱼的氧化应激。过氧化氢酶和谷胱甘肽过氧化物酶）和免疫抑制（溶菌酶减少，50％溶血补体减少，总免疫球蛋白和吞噬指数降低），但MSO可以消除氧化损伤的致命作用。此外，氨中毒可能会诱导抗氧化酶编码基因（SOD，CAT和GPx）下调，而炎症细胞因子基因（TNFα，IL-1β和IL-8）的转录上调，表明免疫抑制与炎症可能有关对鱼的氧化应激。过氧化氢酶和谷胱甘肽过氧化物酶）和免疫抑制（溶菌酶减少，50％溶血补体减少，总免疫球蛋白和吞噬指数降低），但MSO可以消除氧化损伤的致命作用。此外，氨中毒可能会诱导抗氧化酶编码基因（SOD，CAT和GPx）下调，而炎症细胞因子基因（TNFα，IL-1β和IL-8）的转录上调，表明免疫抑制与炎症可能有关对鱼的氧化应激。