Triploid rainbow trout is a hypoxia-sensitive fish species, and is susceptible to death in summer with high water temperature induced acute hypoxia. The study was conducted to evaluate the effect of high protein diet and high carbohydrate diet on hypoxic tolerance of triploid rainbow trout. Two isolipidic and isoenergetic diets with low protein-high carbohydrate level (LPHC) and high protein-low carbohydrate level (HPLC) were specifically formulated. After the feeding trial with 80 days, two group fish were treated with acute hypoxic challenge. Plasma biochemical parameters, hepatic anti-stress, antioxidant and immune related genes expression, and hepatic glucose, lipid, protein and amino acid metabolism related genes expression were then analyzed. The results showed that compared with HPLC diet, LPHC diet could result in excessive plasma levels of alanine aminotransferase (ALT; 36.3 VS 14.0 U/L), aspartate aminotransferase (AST; 978 VS 366 U/L), alkaline phosphatase (ALP; 374 VS 204 U/L), creatine phosphokinase (CPK; 7538 VS 4937 U/L) and lactate dehydrogenase (LDH; 940 VS 451 U/L). In addition, HPLC diet could remodel metabolism of glucose, lipid and protein based on the mRNA expression levels of the genes regulating glycometabolism, lipometabolism, and protein and amino acids metabolism. HPLC diet also enhanced the mRNA expression levels of the genes regulating anti-stress (, and ), antioxidant (, , , and ) and immune (, , and ). In total, LPHC diet could aggravate hypoxic stress of triploid rainbow trout, while HPLC diet could improve fish hypoxic tolerance.

中文翻译：

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高蛋白低碳水化合物饮食可提高三倍体虹鳟（Oncorhynchus mykiss）的缺氧耐受性：对急性缺氧生理和代谢反应的影响

三倍体虹鳟鱼是缺氧敏感鱼类，夏季水温高导致急性缺氧，容易死亡。本研究旨在评价高蛋白饮食和高碳水化合物饮食对三倍体虹鳟耐缺氧能力的影响。特别配制了两种低蛋白-高碳水化合物水平（LPHC）和高蛋白-低碳水化合物水平（HPLC）的等脂和等能量饮食。 80天饲养试验后，两组鱼均接受急性缺氧激发。然后分析血浆生化参数，肝脏抗应激、抗氧化和免疫相关基因表达，以及肝脏葡萄糖、脂质、蛋白质和氨基酸代谢相关基因表达。结果显示，与HPLC饮食相比，LPHC饮食可导致血浆丙氨酸转氨酶（ALT；36.3 VS 14.0 U/L）、天冬氨酸转氨酶（AST；978 VS 366 U/L）、碱性磷酸酶（ALP；374）水平过高。 VS 204 U/L）、肌酸磷酸激酶（CPK；7538 VS 4937 U/L）和乳酸脱氢酶（LDH；940 VS 451 U/L）。此外，HPLC饮食可以根据调节糖代谢、脂肪代谢、蛋白质和氨基酸代谢的基因的mRNA表达水平来重塑葡萄糖、脂质和蛋白质的代谢。 HPLC饮食还增强了调节抗应激（、和）、抗氧化（、、、和）和免疫（、、和）基因的mRNA表达水平。综上所述，LPHC饲料会加重三倍体虹鳟鱼的缺氧应激，而HPLC饲料则可以提高鱼的耐缺氧能力。