Production of u 1-antitrypsin (AT) in transgenic cows has a great value in the field of medicine. The present study was conducted to determine the effect of chemically defined KSOM media on in vitro development of bovine transgenic nuclear transfer (NT) embryos. An expression plasmid for human AT was constructed by inserting a bovine beta-casein promoter, a green fluorescent protein (GFP) marker gene, and a human AT target gene into a pcDNA3 plasmid. Cumulus cells as donor nuclei in NT were collected from a Holstein cow and transfected by lipid-mediated method using FuGene6 (Roche Molecular Biochemicals, USA) as reagent. GFP expressed cumulus cells were introduced into recipient oocytes under DIC microscopy equipped with FITC filter set. After electrical fusion and chemical activation, reconstructed embryos were cultured in 1) SOF + 0.8% BSA, 2) KSOM + 0.8% BSA, 3) KSOM + 10% FBS and 4) KSOM +0.01% PVA for 192 h at 39 with 5% , 5% and 90% in humidified condition. The development of the embryos was recorded and the GFP expression in blastocyst was determined under FITC filter. The average fusion rate was 73.8% (251/340; n=8). The development rates to 2-4 cells, morula, blastocysts and expression rates in blastocysts varied from 70.3 to 76.5%, 30.2 to 33.8%, 25.4 to 33.8% and 11.8 to 15.6%, respectively. The difference in development and expression rates of embryos among 4 culture groups was not significant (P>0.05). This study indicates that chemically defined KSOM medium is also able to support development of bovine transgenic NT embryos at similar rate of SOF or KSOM supplemented with BSA or serum.

The International Union for Conservation of Nature and Natural Resources (IUCN) considers the western/lowland bongo Tragelaphus eurycerus eurycerus to be a threatened species, and the eastern/mountain bongo Tragelaphus eurycerus isaaci an endangered species［1］. Although extinction is considered by many biologists to be a natural process during evolution, the exponential growth of the human population has drastically and prematurely reduced the numbers and genetic diversity of many species［2］. Species have evolved to adapt to a specific habitat or environment that meet their survival needs. Alteration or destruction of their habitat results in a species becoming incapable of adapting and hence becoming threatened with extinction. A widespread scientific and public consensus has emerged suggesting that governments should assign high priority to the maintenance of biological diversity via habitat preservation and management far species conservation［3］. Unfortunately, the loss of biological diversity far surpasses the available conservation resources and species are lost forever on a daily basis［4］. Notwithstanding the focus on habitat preservation and wildlife management, conservation biologists have also become increasingly interested in using the technologies of reproductive and developmental biology to help manage or rescue endangered species［5］.