The aim of this experiment was to study the effects of α⁃ketoglutarate ( AKG) supplementation on liver glutamine ( Gln) content, antioxidant capacity and the expressions of growth hormone ( GH) and insulin⁃like growth factorⅠ( IGF⁃Ⅰ) genes of juvenile hybrid sturgeon fed different protein source diets. Four exper⁃imental diets were formulated using soybean protein concentrate ( SPC ) or SPC+fish meal ( FM ) as protein sources and with 0 or 1% AKG. A total of 500 juvenile hybird sturgeon with an average initial body weight of (7.65±0.04) g were randomly divided into 4 groups with 5 replicates per group and 25 fish per replicate. The experiment lasted for 8 weeks. The results showed that the supplementation of 1% AKG significantly increased the liver Gln content and glutamine synthetase( GS) activity ( P<0.05) , but had no significant effect on liver alkaline phosphatase ( ALP) activity ( P>0.05) . Protein source had no significant effects on liver Gln content, GS activity and ALP activity ( P>0.05) , and the protein source and AKG supplemental level had no significant interaction effects on liver Gln content, GS activity and ALP activity (P>0.05). The supplementation of 1%AKG significantly decreased the content of liver malondialdehyde ( MDA) , and increased the content of liver glutathione ( GSH) ( P<0.05) . Compared with the SPC+FM, SPC as the protein source significantly increased the content of liver GSH ( P<0.05) . Protein source and AKG supplemental level had no significant effects on liver superoxide dismutase (SOD) and catalase (CAT) activities (P>0.05), and protein source and AKG supplemental level had no significant interaction effects on all liver antioxidant indices ( P>0.05) . The supple⁃mentation of 1% AKG significantly increased the relative expression levels of liver IGF⁃Ⅰ and GH genes ( P<0.05) . Compared with the SPC+FM, SPC as the protein source significantly increased the relative expression levels of liver IGF⁃Ⅰand GH genes ( P<0.05) . protein source and AKG supplemental level had no significant interaction effects on the relative expression levels of liver IGF⁃Ⅰ and GH genes (P>0.05). In conclusion, the supplementation of 1% AKG in juvenile hybrid sturgeon diet increase the content of Gln by increasing the GS activity, reduce the content of MDA by increasing the content of GSH, and can improve the liver growth related gene IGF⁃Ⅰ and GH expression.%本试验旨在研究不同蛋白质源饲料中添加α－酮戊二酸对杂交鲟（ Acipenser schrenckii♀×Acipenser baeri ）幼鱼肝脏谷氨酰胺（ Gln）含量、抗氧化能力及生长激素（ GH）、胰岛素样生长因子－Ⅰ（ IGF⁃Ⅰ）基因表达的影响。分别以大豆浓缩蛋白和大豆浓缩蛋白＋鱼粉为蛋白质源，设2个α－酮戊二酸（AKG）添加量（0和1％），配制4种试验饲料。选取平均体重为（7．65±0．04） g的杂交鲟幼鱼500尾，随机分为4组，每组5个重复，每个重复25尾，养殖周期为8周。结果表明：饲料中添加1％ AKG 显著提高肝脏 Gln 含量和谷氨酰氨合成酶（ GS ）活性（ P＜0．05），对肝脏碱性磷酸酶（ALP）活性无显著影响（P＞0．05）。蛋白质源对肝脏Gln含量、GS活性和ALP活性无显著影响（P＞0．05），且蛋白质源和AKG添加量对肝脏Gln含量、GS活性和ALP活性无显著交互作用（ P＞0．05）。饲料中添加1％ AKG显著降低肝脏丙二醛（ MDA）含量，显著提高肝脏还原型谷胱甘肽（ GSH）含量（ P＜0．05）。与大豆浓缩蛋白＋鱼粉作为蛋白质源相比，大豆浓缩蛋白作为蛋白质源显著提高肝脏GSH含量（ P＜0．05）。蛋白质源和AKG添加量对肝脏超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性均无显著影响（P＞0．05），且蛋白质源和AKG添加量对肝脏各抗氧化指标无显著交互作用（ P＞0．05）。饲料中添加1％ AKG显著提高肝脏GH、IGF⁃Ⅰ基因的相对表达量（ P＜0．05）。与大豆浓缩蛋白＋鱼粉作为蛋白质源相比，大豆浓缩蛋白作为蛋白质源显著提高肝脏IGF⁃Ⅰ和GH基因的相对表达量（ P＜0．05）。蛋白质源和AKG添加量对肝脏GH、IGF⁃Ⅰ基因的相对表达量无显著交互作用（ P＞0．05）。综上所述，杂交鲟幼鱼饲料中添加1％ AKG可以通过提高肝脏中GS的活性进而提高Gln的含量，通过提高肝脏中GSH的含量进而降低MDA的含量，并可提高肝脏中生长相关基因GH、IGF⁃Ⅰ的表达。
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