不同糖及糖水平对松浦镜鲤GH/IGF-Ⅰ基因表达和鱼体组成的影响

Effects of different dietary carbohydrates and carbohydrate levels on GH/IGF-Ⅰ mRNA expression and the fish body composition of juvenile mirror carp( Cyprinus carpio)

旨在探讨不同糖及糖水平对松浦镜鲤GH(growth hormone)/IGF-Ⅰ(Insulin-like growth factor-Ⅰ)基因表达和鱼体组成的影响。选用初始体质量(8.30±0.15)g的松浦镜鲤420尾,随机分为4组,每组3个重复,每个重复35尾鱼。分别饲喂添加25%和50%的淀粉(LS/HS)和葡萄糖(LG/HG)饲料,实验周期为60 d。实验结果表明:HS组和LS组的GH基因表达量显著低于LG组(P<0.05)。HS组的IGF-Ⅰ基因表达量显著低于LS组和LG组(P<0.05)。各实验组的鱼体粗蛋白含量差异不显著(P>0.05)。HS组的水分值显著低于其他实验组(P<0.05),粗脂肪含量显著高于其他各组(P<0.05)。氨基酸组成结果显示,HS组的Leu含量和Cys含量显著低于LG组(P<0.05),Ala含量显著低于LS组和LG组(P<0.05),其他各组间差异不显著(P>0.05);其他氨基酸含量各组间差异不显著(P>0.05)。必需氨基酸总量、半必需氨基酸总量、非必需氨基酸总量和总氨基酸含量各组间差异不显著(P>0.05)。综上,饲料中添加高水平的淀粉抑制了GH基因和IGF-Ⅰ基因的表达,同时增加了全鱼粗脂肪含量、降低了一些氨基酸的含量。

The effects of the different dietary carbohydrates and different carbohydrate levels on GH/IGF-Ⅰgene expression,body composition and amino acid composition were studied in juvenile mirror carp（ Cyprinus carpio）. 420 Songpu mirror carp（ mean weight = 8. 30 ± 0. 15g） were randomly divided into 4 dietary treatments triplicate groups and 35 fish per triplicate. The fish in 4 groups were fed two carbohydrates（ starch and glucose） diets with two levels（ 250 g/kg and 500 g/kg）（ LS/HS/LG/HG） and were reared for 60 days.Results showed that the GH mRNA expression levels of HS and LS groups were significantly lower than that of LG group（ P〉0.05）. The IGF-Ⅰ mRNA expression level of HG group was significantly lower than that of LS and LG groups（ P〉0.05）. The crude protein was not significantly different among groups（ P〉0.05）.The moisture of HS group was significantly lower than that of the other groups（ P〉0.05）. The crude fat of HS group was significantly higher than that of the other groups（ P〉0.05）. The body amino acid composition results showed that Leu and Cys contents of HS group were significantly lower than those of LG group（ P〉0.05）. Ala content of HS group was significantly lower than that of LS and LG groups（ P〈0.05）. The other amino acids contents were not significantly different among groups（ P〉0.05）. The total essential amino acids,semi-essential amino acid,total non-essential amino acids and total amino acids had no significant difference mong groups（ P〉0.05）. In conclusion,high dietary starch could inhibit the expression of GH and IGF-Ⅰ genes,increase body crude fat content and decrease some amino acids contents.