Sviluppo embrionale di oociti di ovino dopo ICSI: effetto dell’attivazione e del trattamento del materiale seminale.

The effect of oocyte activation and sperm treatment on development of sheep embryos derived from ICSI of IVM oocytes was analyzed. Oocytes were injected with frozen-thawed ram semen; motile spermatozoa, selected by swim up technique, were used immediately, or after incubation with 0.1% Triton X-100 for 5 min. The injected oocytes were activated by exposure to 5 M ionomycin for 5 min followed by culture for 3 h and a further 3 h culture in 2mM 6-DMAP or cultured without activation. After 8 days of in vitro culture, embryo development was recorded. Results evidenced that i) sperm treatment significantly decreased cleavage rate both in activated and not activated groups; ii) activation without sperm treatment allowed to obtain the highest cleavage rate and development to blastocyst stage. iii) sperm treatment combined with activation did not increase blastocyst development. These results demonstrated that oocyte activation but not sperm treatment is necessary for increasing embryo development in sheep oocytes.