Molecular Cloning and Sequence Analysis of IGF-Ⅰfrom Triangular Bream (Megalobrama terminalis)

The insulin-like growth factor Ⅰ(IGF-Ⅰ) gene of triangular bream (Megalobrama terminalis)(GenBank No.AY247412)(Tb)was cloned for the first time from liver by RT-PCR. Thenucleotide sequence analysis showed the Tb IGF-ⅠcDNA consisted of 486 nucleotides andencoded 117 amino acids including B, C, A, D and E five domains. Analysis of E-domainindicated that cloned Tb IGF-Ⅰbelonged to IGF-ⅠEa-2 subtype. Identity analysis showedthe IGF-Ⅰnucleotide sequence shared 99.8% homology with bluntnose bream, 88.8% withgrass carp, 85.8% with common carp; the pre-IGF-Ⅰamine acid sequence shared 99.4% withbluntnose bream, 88.8% with grass carp, 85.4% homology with common carp. In the CyprinusCarpio, the higher homology of nucleotide sequence and amino acid sequence in IGF-Ⅰshowed that the closer relationship the fishes have. These results could provide basicdata for the research on Tb germplasm and the development and utilization of biologicalfeed additives.

不同蛋白、脂肪水平对杂交鲂幼鱼生长性能及饲料利用的影响

试验采用2×4双因子设计,蛋白水平为28%、32%、36%、40%,脂肪水平为6%、10%,经过8周的养殖试验,探讨不同蛋白、脂肪水平对杂交鲂(Megalobrama terminalis♀×Erythroculter ilishaeformis♂)生长性能及饲料利用的影响。结果表明,饲料蛋白水平与杂交鲂生长性能存在一定的正相关关系,与饵料系数存在负相关关系,当饲料蛋白含量为40%时,杂交鲂的增重有所下降,饵料系数有所增高;10%饲料脂肪水平对提高杂交鲂的生长性能和饲料利用的影响存在显著作用(P<0.05),饲料蛋白、脂肪水平对杂交鲂生长性能无明显的交互作用(P>0.05)。以增重率为评价指标,杂交鲂幼鱼的适宜蛋白和脂肪水平为36.44%和10%。