Vitrification of immature oocytes in pigs.

Cryopreservation of oocytes is an important technology for the in vitro gene banking of female germplasm. Although slow freezing is not feasible, porcine oocytes survive vitrification at high rates. Cryopreservation at the germinal vesicle stage appears to be more advantageous than that at the metaphase-II stage.

Serum-free spontaneously immortalized bovine oviduct epithelial cell conditioned medium promotes the early development of bovine in vitro fertilized embryos.

Embryonic transfer of bovine blastocysts produced using in vitro fertilization (IVF) is widely used, although the challenge of compromised conception rates remains. Using bovine oviduct epithelial cells (BOEC) to improve embryo culture conditions has attracted attention, particularly since the recent discovery of extracellular vesicles from BOEC. The selection of embryos for transfer has also been the subject of various studies, and a set of evaluation criteria to predict pregnancy success has been suggested, in which the embryos are judged by their kinetics and morphology at the early stages.

Electroporation-mediated genome editing in vitrified/warmed porcine zygotes obtained in vitro.

Clustered regularly interspaced short palindromic repeats (CRISPR)-associated 9 (Cas9) system is the most efficient and widely used technology for genome editing in all sorts of organisms, including livestock animals. Here, we examined the feasibility of CRISPR/Cas9-derived genome editing (GE) in vitrified porcine zygotes, where the flexible planning of experiments in time and space is expected. OCT4 and CD46 genes were targeted, and the Cas9/sgRNA ribonucleoprotein complexes (RNP) were electroporated into zygotes at 2 h after warming.

The Effects of an Oocyte Maturation System and Chlorogenic Acid Supplementation during Embryo Culture on the Development of Porcine Cloned Embryos Derived from Native Vietnamese Ban Pigs.

The aim of this study was to improve the production efficiency of Vietnamese native Ban pig embryos using somatic cell nuclear transfer (SCNT). Fibroblast cells from Ban pigs were injected into the enucleated cytoplasts of crossbred gilts, and the reconstructed embryos were subsequently cultured. In the first experiment, cytoplasts were isolated from oocytes matured in either a defined porcine oocyte medium (POM) or in TCM199 medium supplemented with porcine follicular fluid.

Vitrification of porcine immature oocytes and zygotes results in different levels of DNA damage which reflects developmental competence to the blastocyst stage.

The present study investigated the effects of vitrification of porcine oocytes either at the immature Germinal Vesicle (GV) stage before in vitro maturation (GV-stage oocytes) or at the pronuclear stage after in vitro maturation and fertilization (zygotes) on DNA integrity in relevance with their subsequent embryo development. Vitrification at the GV stage but not at the pronuclear stage significantly increased the abundance of double-strand breaks (DSBs) in the DNA measured by the relative fluorescence after γH2AX immunostaining. Treatment of GV-stage oocytes with cryoprotectant agents alone had no effect on DSB levels.