Med. Weter. 81
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| MAGDALENA PROFASKA, JURIJ KOSENIUK, MONIKA STEFANIUK-SZMUKIER, MACIEJ WITKOWSKI |
| The First Equine Blastocyst in Poland Cultured after ICSI of Oocytes Derived by TVA-OPU. |
| The aim of this study was to demonstrate the feasibility of obtaining equine embryos developed to the blastocyst stage using oocyte retrieval by transvaginal ultrasound-guided ovum pick-up (OPU-TVA) and fertilization by intracytoplasmic sperm injection (ICSI) within a fully implemented domestic laboratory setting, where such procedures have not previously been successfully completed, as a basis for further optimization and standardization of in vitro equine embryo production. Materials and methods: Two OPU sessions were performed in five warmblood mares under continuous veterinary care. Oocytes were retrieved using transvaginal ultrasound-guided ovum pick-up (OPU-TVA), followed by in vitro maturation (IVM) and fertilization by intracytoplasmic sperm injection (ICSI) using frozen stallion semen. Embryos were cultured under sequential conditions to the blastocyst stage, and embryonic development was monitored. The embryo that reached the early blastocyst stage was cryopreserved by vitrification. Results: In two OPU sessions, five warmblood mares yielded 25 oocytes. Of these, 16 oocytes (64%) were morphologically competent and subjected to ICSI. Following in vitro maturation for 24-26 h, 15 of 24 oocytes (62.5%) reached metaphase II, while the single oocyte cultured for 35 h also matured. Post-ICSI cleavage occurred in 12 oocytes, leading to one morula and one blastocyst, with the blastocyst originating from the 35 h IVM oocyte. These findings highlight variability in oocyte developmental competence between mares and the impact of IVM duration on embryo development. Conclusions: The production of the first mare blastocyst in Poland marks a major milestone in national equine reproductive biotechnology, demonstrating the effectiveness of the OPU-ICSI procedure. This achievement enables breeders to access advanced assisted reproductive technologies domestically, reducing the need for transport of animals or genetic material, and lays the groundwork for the development and commercialization of in vitro reproduction programs in Poland. Continued research and optimization of oocyte recovery and ICSI outcomes are needed to increase the efficiency and reproducibility of the method. |
| Keywords: OPU, ICSI, blastocyst, horse, reproductive biotechnology, horse breeding |