EN
The aim of this study was to obtain embryos after assisted fertilization of oocytes collected from slaughtered mares and matured in vitro by an intracytoplasmic sperm injection (ICSI) and to establish optimal conditions for the in vitro culture of the embryos. Oocytes were collected by the scraping method and cultured in vitro in TCM with Earl’s salts supplemented with 20% FBS, 5 g/ml FSH, estradiol 1 g/ml, pyruvate and glutamine. After a 30-hour in vitro culture oocytes that had reached the metaphase II stage were subjected to an intracytoplasmic sperm microinjection (ICSI) with frozen semen. After thawing, a motile sperm selection was carried out by the „swim up” method. Then the sperm was immobilized, aspirated into an injection pipette, and introduced into the cytoplasm of an oocyte. Microinjected oocytes were transferred onto a culture medium: DMEM F12 or SOF. The control group consisted of oocytes subjected to microinjection without sperm (sham ICSI). Oocytes that did not show signs of development and embryos in different developmental stages were fixed and stained with Hoechst fluorochrome. The in vitro culture of embryos in the DMEM F12 medium produced only early stages of development (pronucleus, two-blastomere embryos). In contrast, the in vitro culture in the SOF medium produced embryos in the morula stage (6.8%). In the control group, no signs of embryonic development were observed.