Advances in Swine In Vitro Embryo Production Technologies

Abstract

Contents Recent advances in new technologies to produce cloned and genetically modified pigs involve manipulating oocytes and/or embryos in vitro. Although a great deal of progress has been made, the current IVM–IVF systems still result in major problems: a high rate of polyspermy; and a low development rate and low quality of blastocysts for in vitro compared with the in vivo–produced embryos. This study summarizes recent advancements in IVM–IVF–IVC porcine systems. Recent methods to select monospermic embryos are also discussed. Finally, achievements in vitrification and in somatic cell nuclear transfer are discussed.

Obtaining farm animal embryos <i>in vitro</i>

“…In pigs, chromatin decondensation defects are sometimes observed in the formation of the male pronucleus (Gil et al, 2010).…”

“…Immature oocytes are surrounded by several tightly packed layers of granulosa cells called the corona radiata, with which they form the cumulus-oocyte complex (COC), and a cluster of cells forming the cumulus oophorus (Abeydeera, 2002;Cognie et al, 2003;Hoshi, 2003;Nagai et al, 2006;Lonergan, 2007;Lonergan and Fair, 2008;Gil et al, 2010;Paramio, 2010;Dang-Nguyen et al, 2011). In mares, oocytes can be surrounded by both tightly packed and dispersed layers of the corona radiata, but both types of oocytes are competed for maturation (Squires et al, 2003;Betteridge, 2006;Hinrichs, 2010Hinrichs, , 2010a.…”

“…This encompasses nuclear and cytoplasmic modifications and their mutual interactions, changes in embryo metabolism, embryonic genome activation, modifications of gene expression, formation of the morula and compaction of blastomeres, formation of the blastocyst with a characteristic structure named the blastocyst cavity that arises as a result of cavitation, and formation of additional structures such as the capsule in the horse embryos (Abeydeera, 2002;Cognie et al, 2003;Hoshi, 2003;Nagai et al, 2006;Lonergan, 2007;Lonergan and Fair, 2008;Gil et al, 2010;Paramio, 2010;Dang-Nguyen et al, 2011). The capsule is a structure located between trophoblast and zona pellucida, which is generated by the embryo.…”

“…The granulosa cells of the corona radiata play an important role in the maturation of the oocyte, being responsible for contact of the oocyte with the environment and, therefore, mediating the hormonal and metabolic regulation of this process (Abeydeera, 2002;Cognie et al, 2003;Hoshi, 2003;Nagai et al, 2006;Lonergan, 2007;Lonergan and Fair, 2008;Gil et al, 2010;Paramio, 2010;Dang-Nguyen et al, 2011).…”

“…All of these requirements are characteristic of the respective farm animal species and have been described in detail in the literature: cattle (Hoshi, 2003;Lonergan, 2007;Lonergan and Fair, 2008), pigs (Abeydeera, 2002;Nagai et al, 2006;Lonergan and Fair, 2008;Gil et al, 2010;Dang-Nguyen et al, 2011), sheep and goats (Cognie et al, 2003;Paramio, 2010), and horses (Squires at el., 2003;Betteridge, 2006Betteridge, , 2007Hinrichs, 2010).…”