Oocyte maturation under a biophoton generator improves preimplantation development of pig embryos derived by parthenogenesis and somatic cell nuclear transfer

ABSTRACT

This study was conducted to determine the effects of biophoton treatment during in vitro maturation (IVM) and/or in vitro culture (IVC) on oocyte maturation and embryonic development in pigs. An apparatus capable of generating homogeneous biophoton energy emissions was placed in an incubator. Initially, immature pig oocytes were matured in the biophoton-equipped incubator in medium 199 supplemented with cysteine, epidermal growth factor, insulin, and gonadotrophic hormones for 22 h, after which they were matured in hormone-free medium for an additional 22 hr. Next, IVM oocytes were induced for parthenogenesis (PA) or provided as cytoplasts for somatic cell nuclear transfer (SCNT). Treatment of oocytes with biophoton energy during IVM did not improve cumulus cell expansion, nuclear maturation, intraoocyte glutathione content, or mitochondrial distribution of oocytes. However, biophoton-treated oocytes showed higher (p < 0.05) blastocyst formation after PA than that in untreated oocytes (50.7% vs. 42.7%). In an additional experiment, SCNT embryos produced from biophoton-treated oocytes showed a greater (p < 0.05) number of cells in blastocysts (52.6 vs. 43.9) than that in untreated oocytes. Taken together, our results demonstrate that biophoton treatment during IVM improves developmental competence of PA- and SCNT-derived embryos.