本试验旨在研究不同蛋白质水平饲料中添加α-酮戊二酸(α-ketoglutarate,AKG)对松浦镜鲤生长性能、体成分和血清生化指标的影响。试验设4个蛋白质水平,分别为28%、31%、34%和37%;每个蛋白质水平下设3个AKG浓度,分别为0(对照)、0.75%和1.50%。试验选取平均体重为(61.28±3.40) g的松浦镜鲤720尾,随机分成12组,每组3个重复,每个重复20尾鱼,试验期为8周。结果表明:各个蛋白质水平下,饲料中添加AKG均有提高松浦镜鲤增重率、蛋白质效率和降低饲料系数的趋势,除34%蛋白质水平下松浦镜鲤增重率显著提高(P<0.05)外,其余差异不显著(P>0.05)。各个蛋白质水平下,饲料中添加AKG对松浦镜鲤肝体指数、脏体指数和肥满度均无显著影响(P>0.05)。28%蛋白质水平下,1.50%AKG组血清甘油三酯(TG)含量显著低于对照组(P<0.05),与0.75%AKG组差异不显著(P>0.05)。31%蛋白质水平下,1.50%AKG组血清白蛋白(ALB)含量和谷丙转氨酶(ALT)活性显著高于其他组(P<0.05);0.75%和1.50%AKG组血清尿酸(UA)和TG含量显著低于对照组(P<0.05)。34%蛋白质水平下,0.75%AKG组血清总蛋白(TP)和TG含量显著高于对照组(P<0.05)。37%蛋白质水平下,1.50%AKG组血清ALT活性和UA含量显著高于其他组(P<0.05);0.75%和1.50%AKG组血清谷草转氨酶(AST)活性显著高于对照组(P<0.05)。各个蛋白质水平下,饲料中添加AKG对血清球蛋白(GLB)、总胆固醇(TCHO)、肌酐(CREA)含量及碱性磷酸酶(ALP)活性均无显著影响(P>0.05)。蛋白质水平和AKG浓度的交互作用除对鱼体粗灰分、血清UA和TG含量存在显著影响(P<0.05)外,对其他体成分指标和血清生化指标均无显著影响(P>0.05)。由此得出,饲料中添加适量的AKG可以在一定程度上提高松浦镜鲤的增重率和蛋白质效率,降低饲料系数,促进鱼体蛋白质和脂肪代谢。

This experiment was aimed to study the effects of α-ketoglutarate (AKG) supplementation in different protein level diets on growth performance, body composition and serum biochemical indices of Songpu mirror carp. Four protein levels (28%, 31%, 34% and 37%, respectively) were designed in the experiment, and 3 AKG concentrations were designed under each protein level. A total of 720 Songpu mirror carp with an average body weight of (61.28±3.40) g were divided into 12 groups with 3 replicates per group and 20 fish per replicate. The experiment lasted for 8 weeks. The results showed as follows: under each protein level, AKG supplementation showed a tendency to increase weight gain rate (WGR) and protein efficiency ratio (PER) and decrease feed conversion ratio (FCR) of Songpu mirror carp, but the differences were not significant (P>0.05) except the WGR under the 34% protein level (P<0.05). AKG supplementation had no significant effects on hepatosomatic index (HSI), visceralsomatic index (VSI) and condition factor (CF) under each protein level (P>0.05). Under the 28% protein level, the serum triglyceride (TG) content in 1.50%AKG group was significantly lower than that in control group (P<0.05), but there was no significant difference between 0.75% and 1.50%AKG groups (P>0.05). Under the 31% protein level, the serum albumin (ALB) content and alanine aminotransferase (ALT) activity in 1.50%AKG group were significantly higher than those in other groups (P>0.05); the serum uric acid (UA) and TG contents in 0.75% and 1.50%AKG groups were significantly lower than those in control group (P<0.05). Under the 34% protein level, the serum total protein (TP) and TG contents in 0.75%AKG group were significantly higher than those in control group (P<0.05). Under the 37% protein level, the serum ALT activity and UA content in 1.50%AKG group were significantly higher than those in other groups (P<0.05); the serum aspartate aminotransferase (AST) activity in 0.75% and 1.50%AKG groups was significantly higher than that in control group (P<0.05). AKG supplementation had no significant effects on serum globulin (GLB), cholesterol (TCHO) and creatinine (CREA) contents and alkaline phosphatase (ALP) activity under each protein level (P>0.05). The interaction of the protein level and AKG concentration had significant effects on whole fish ash and serum UA and TG contents (P<0.05), and had no significant effects on other body composition indices and serum biochemical indices (P>0.05). It is concluded that suitable supplementation of AKG in diets can improve WGR and PER, reduce FCR, and promote protein and fat metabolism of Songpu mirror carp to some extent.