Reproductive Technology

Production of Piglets Derived from In Vitro-Produced Blastocysts Fertilized and Cultured in Chemically Defined Media: Effects of Theophylline, Adenosine, and Cysteine During In Vitro Fertilization

Abstract
In order to further develop defined conditions for in vitro fertilization (IVF) and culture (IVC) of in vitro-matured porcine oocytes, we evaluated the effects of theophylline, adenosine, and cysteine in a chemically defined medium during IVF. Furthermore, viability to full term of in vitro produced blastocysts after IVF and IVC in chemically defined media, was also investigated by embryo transfer to recipients. A chemically defined medium (Porcine Gamate Medium: PGM) was modified from Porcine Zygote Medium (PZM-4) which has been already established. PGM was used as a basal medium of IVF and PZM-4 was for the culture of presumptive zygotes. Addition of 2.5 mM theophylline to PGM significantly increased the percentage of male pronuclear formation, compared with control (no addition). Moreover, addition of 1 µM adenosine to PGM supplemented either with or without 2.5 mM theophylline significantly reduced the number of penetrated spermatozoa, compared to control (no addition of adenosine). Supplementation with 0.2 µM cysteine in PGM containing both 2.5 mM theophylline and 1 µM adenosine further increased the percentage of development to the blastocyst stage, compared with no supplementation of cysteine, while there was no difference in fertilization parameters, such as monospermy and pronuclear formation, regardless of presence or absence of theophylline and adenosine. When Day-5 blastocysts were transferred into 4 recipients (20-25 blastocysts per recipient), all recipients became pregnant and farrowed a total of 21 alive piglets. The present results clearly demonstrated that porcine blastocysts can be produced by IVF and IVC in chemically defined media and that they can develop to full term after embryo transfer.

Key words: Embryo • Assisted Reproductive Technology • Early development • In vitro fertilization

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				H. Nagashima, K. Hiruma, H. Saito, R. Tomii, S. Ueno, N. Nakayama, H. Matsunari, and M. Kurome Production of Live Piglets Following Cryopreservation of Embryos Derived from In Vitro-Matured Oocytes Biol Reprod, May 1, 2007; 76(5): 900 - 905. [Abstract] [Full Text] [PDF]