Introduksi dan ekspresi gen hormon pertumbuhan ikan nila (Oreochromis niloticus) pada ikan lele (Clarias sp)

Abstract

The gene transfer technology applied in commercially important aquatic animals is to enhance genetic quality of aquaculture broodstock. This study was conducted to introduce gene encoding growth hormone (GH) in catfish embryos to improve its growth rate. In fish, microinjection was the earliest technique developed to introduce foreign DNA into fertilized eggs. However, the opaquness, stickiness and buoyancy of the embryos, the invisibility of the pronuclei, the togness of the chorion, and the higher mortality of injected eggs make this technique time consuming and requires sophisticated skills. Electropration method is able to produce mass fish transgenic. In this study, we transferred a plasmid containing GH gene of Nile tilapia (tiGH), driven by medaka β-actin promoter (mBP) into catfish using microinjection and electroporation methods, to obtain growth enhanced transgenic fish. The DNA solution (mBP-tiGH) used was 50 μg/ml in sterile distillated water. The parameter observed was survival rate of embryos (SRe), hatching rate (HR), and the percentage of individual carrying mBP-tiGH. Transgenic individual carrying tiGH was identified by PCR ( Polymerase Chain Reaction) method with specific primer for tiGH gene. The analysis of gene expression was conducted by RT-PCR. The results of research from 100 catfish embryos showed that control uninjected treatment was higher SRe and HR of eggs fertilized while the Sre and HR in electroporated-sperm was similar with control (SRe 98.5%; HR 91.2%). Percentage of catfish carrying tiGH gene by microinjection methods was 42.86% (12/28) while by electroporation methods was 87% and 93%. Germ line transmission of the transgene at first generation was 4.0 % - 8.33%. The growth of catfish in founder generation was not different between transgenic and nontransgenic. The growth of transgenic catfish at first generation were up to 7 fold higher compared with nontransgenic fish.