The Use of Reproductive Technologies to Produce Transgenic Goats

Recombinant DNA technology has revolutionized the production of therapeutic proteins. Thus, genes of a great number of human proteins have already been identified and cloned. The use of farm animals as bioreactors may be the better choice to produce recombinant therapeutic proteins. For this activity, the term “pharming” was created, referring to the use of genetic engineering to obtain a transgenic or genetically modified animal. Considering the advantages and disadvantages of livestock species, goats appear as a very good model. In addition, the first human commercially approved biological drug (antithrombin (AT)) was produced from the milk of transgenic goats. The aim of this chapter is to present various reproductive technologies used to obtain transgenic goats secreting recombinant proteins in milk. Initially, this chapter presents the methods for embryo production (in vivo and in vitro) to realize the DNA microinjection in pronuclear embryos. Thus, the techniques of superovulation of donors (in vivo embryo production) and ovarian stimulation for oocyte recovery (in vitro embryo production) are described. Also, the methods for DNA microinjection and embryo transfer are detailed in this chapter. Finally, this chapter describes the reproductive procedures used for obtaining transgenic goats by cloning

Production of transgenic goat (Capra hircus) with human Granulocyte Colony Stimulating Factor (hG-CSF) gene in Brazil

In order to produce transgenic goats with hG-CSF, a total of 24 adult Saanen and 48 adult undefined breed goats were used as donors and recipients, respectively. Donors were estrus-synchronized with vaginal sponges and superovulated by a treatment with 200 mg FSH given twice daily in decreasing doses over 3 days starting 48 h before sponge removal. Ovulation was induced by injecting 100µg GnRH 36 h after sponge removal. The recipients also received an estrus synchronization treatment. Donors were mated with fertile Saanen bucks and, approximately 72 h after sponge removal, zygotes were recovered surgically by flushing oviducts. The recovered zygotes were briefly centrifuged to a reliable visualization of the pronuclei. The DNA construct containing hG-CSF gene flanked by goat and bovine alphas1-casein sequences was injected into pronuclei of 129 zygotes. The microinjected embryos (3-6 per female) were transferred to 27 recipients. Ten recipients became pregnant and 12 kids were born. One transgenic male founder was identified in the group of kids. This is the first report of a birth of a transgenic goat in Latin America