Effect of oocyte quality and activation protocols on bovine embryo development following intracytoplasmic sperm injection


Abstract: The purpose of this study was to investigate the effects of oocyte quality and activation protocols on the in vitro developmental competence of bovine embryos after intracytoplasmic sperm injection (ICSI). Bovine oocytes were grouped as being of excellent, good, and poor quality. All of the oocytes were activated using a calcium ionophore only, ethanol only, and 6-dimethylaminopurine (6-DMAP) following calcium ionophore. For the excellent quality oocytes, cleavage rates after ICSI were 70% in the Ca ionophore + 6-DMAP activation group, 47% in the ethanol activation group, 41.82% in the Ca ionophore group, and 30% in the nontreated control group. Cleavage rates for the good quality oocytes after activation with these different agents were 31%, 16.03%, 19.8%, and 12.9%, respectively, while the rates for the poor quality oocytes were lower (7%, 6%, 2%, and 1%, respectively). In conclusion, using Ca ionophore + 6-DMAP improves the in vitro developmental competence for bovine embryos after ICSI. Furthermore, the results for the excellent quality oocytes indicate the importance of the preselection of the oocytes and activation methods.

Keywords: Bovine oocyte, calcium ionophore, ethanol, intracytoplasmic sperm injection, 6-dimethylaminopurine

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