291 EFFECTS OF ANTIOXIDANT AND CULTURE MEDIUM ON THE DEVELOPMENT OF PORCINE IN VITRO-MATURED–IN VITRO-FERTILIZED EMBRYOS

Abstract

Most cells cultured in vitro are exposed to the risk of injury by free oxygen radicals (FOR). However, some of FOR-induced injury could be reduced by the antioxidants and culture medium used for in vitro embryos. This study was undertaken to examine the effects of the antioxidant and culture medium on the development of porcine in vitro-matured–in vitro-fertilized embryos. In Experiment 1, we treated the porcine oocytes in NCSU23 medium with various concentrations of β-mercaptoethanol (β-ME) to determine the effective concentration of antioxidants during IVM of porcine oocytes. In Experiment 2, we tested different culture media to find the proper culture conditions for in vitro porcine embryos. The porcine oocytes that were matured in NCSU23 medium and then fertilized in mTBM medium were cultured in NCSU23 or porcine zygote medium-5. All steps (maturation, fertilization, and development) were carried out in vitro. Differences were analyzed among treatments using the general linear model (GLM) procedure in the Statistical Analysis System (SAS Institute, Inc., Cary, NC, USA). The results were summarized as follows. Various concentrations of β-ME showed different developmental rates in porcine embryos. The rates of blastocyst formation at Day 7 after IVF were 9.2 ± 1.8 (n = 65), 10.0 ± 4.2 (n = 80), 17.5 ± 1.1 (n = 63), 20.7 ± 1.7 (n = 82), and 14.6 ± 1.4 (n = 82) in oocytes treated with β-ME at 0, 10, 25, 50, and 100 µM during IVM, respectively. Of the concentrations of β-ME tested, 50 µM β-ME markedly increased the rates of blastocyst formation at Day 7 (P < 0.05). The rates of blastocyst formation at Day 7 in the NCSU23 and PZM-5 culture media of porcine IVF-derived embryos were 18.8 ± 2.6 (n = 96) and 15.6 ± 7.1 (n = 77), respectively. The developmental rates were slightly increased in NCSU23, compared with those in PZM-5, but there were no significant differences (P < 0.05) between the NCSU23 and PZM-5 media. In conclusion, these results suggest that the addition of 50 µM β-ME in the IVM medium can improve developmental the rates of porcine embryos in vitro.