Abstract

Sperm of 8 different bulls (3 ejaculates per bull) was used in the present study to evaluate the oxidative burst activity of each individual sperm cell by flow cytometry, correlating this data with the results of in vitro fertilization as well as the further embryo development to the stage of blastocyst. After thawing, the straw content was split in two identical parts. One was employed for the in vitro fertilization, while the other was used for flow cytometry to evaluate sperm oxidative burst activity by an assay using 2,7-dichlorofluorescin diacetate, which based on the oxidation of nonfluorescent DCFH-DA to highly fluorescent 2,7-dichlorofluorescein (DCF) intracellularly during the respiratory burst. As far as embryo production and the sperm metabolism oxidative burst activity is concerned, it was observed that bulls, in which the burst activity was higher, resulted in better results of in vitro fertilization and on the further embryo production. The correlation between burst activity and fertilization rate and further embryo development to blastocysts was, respectively, 95.6% and 87.8% (P.01). This study allows concluding that there is a positive correlation between bull sperm H2O2 production and their ability to fertilize bovine oocytes as well as their development to the blastocyst stage: sperm with high H2O2 production have high metabolic activities and consequently higher fertilizing capacities.