Influence of sequential culture systems on in vitro embryo production in sheep

The present study aimed to produce in vitro sheep embryos using different culture media. A total of 572 presumptive zygotes were cultured in three media: G1/G2 sequential media, synthetic oviduct fluid amino acid (SOFaa), and potassium simplex optimization medium (KSOM). The cleavage rates observed were 162 (84.47±3.07%), 147 (75.93±4.23%), and 140 (72.27±3.50%) for G1/G2, SOFaa, and KSOM, respectively. The cleavage rate was significantly higher in G1/G2 sequential media compared to SOFaa and KSOM. In the G1/G2 sequential media, the mean percentages of embryos progressing to the 4-8 cell, 16-32 cell, morula and advanced stages were 148 (77.15±3.04), 129 (66.39±5.61), 99 (51.77±2.86) and 86 (45.23±2.07) respectively, at different time points. In conclusion, the G1/G2 culture media demonstrated a significantly higher proportion of embryos reaching advanced developmental stages compared to SOFaa and KSOM, indicating its superior suitability for in vitro sheep embryo production.