Lipid Content and Cryotolerance of Porcine Embryos Cultured with Phenazine Ethosulfate

The addition of phenazine ethosulfate (PES) to culture medium was investigated for its effect on pig embryo development, apoptosis, cytoplasmic lipid content and survival after OPS vitrification. Porcine zygotes were cultured in NCSU-23 medium supplemented with 0 (control) or 0.05 μM PES up to the blastocyst stage and were vitrified using OPS technology. Culture of embryos with PES reduced the cytoplasmic lipid content, as measured by fluorescence of blastocysts stained with Nile Red. The survival rate of vitrified blastocysts was slightly enhanced, although not significantly, in the presence of PES compared to the PES-free group (45.2 and 37.9%, respectively). These results showed that culturing porcine embryos in medium with PES increased the proportion of morula and blastocyst formation and reduced the index of DNA fragmentation and the cytoplasmic lipid content of cultured blastocysts. However, the use of PES during in vitro culture had limited effect on porcine blastocyst survival after vitrification.