Effects of oxygen concentration in the gas atmosphere on bovine oocyte maturation, fertilization, and embryo development in vitro

The assisted reproductive technologies (ART) of in vitro maturation (IVM), fertilization (IVF), and culture (IVC) of embryos will have or has had a tremendous impact on alleviating infertility problems in the livestock industry as well as in the field of human reproductive medicine. In an effort to improve the success rate of these ART procedures the following experiments were conducted to determine the optimal atmospheric oxygen concentrations for IVM, IVF, and IVC of bovine embryos: (1) Effect of O{dollar}sb2{dollar} concentration during IVM, (2) IVF, (3) IVC on subsequent embryo cleavage and or development to the blastocyst stage. The cleavage rate of oocytes matured under the typical gas atmosphere of 20% O{dollar}sb2{dollar} was higher than after IVM under reduced oxygen of either 5 or 10% O{dollar}sb2.{dollar} Development rate to the blastocyst stage was higher when embryos were matured under reduced oxygen (5%) when compared to either 10 or 20% O{dollar}sb2.{dollar} Cleavage rates and development rates were similar when bovine embryos were fertilized in either a 5, 10, or 20% oxygen atmosphere. Development to the blastocyst stage was significantly greater when embryos were cultured under reduced (5%) O{dollar}sb2{dollar} when compared to either 10 or 20% O{dollar}sb2.{dollar} In conclusion, reducing O{dollar}sb2{dollar} levels in the gas atmosphere during IVM and IVC, but not during IVF improves bovine embryo development to the blastocyst stage.