Effect of glucose levels and MEM vitamins during the first step of IVC in synthetic oviduct fluid medium on in vitro development of ovine zygotes

This study was carried out to investigate the effects of supplementation of synthetic oviduct fluid (SOF) with glucose and Minimal Essential Medium (MEM) vitamins, during the first step of the in vitro culture (SOFC1) of ovine zygotes. After in vitro fertilization, ovine zygotes were divided into 7 treatments; treatments: 1: SOFC1 without glucose and MEM vitamins, treatment 2: SOFC1 with glucose (1.5 mM) alone (normal SOFC1 medium), treatment 3: SOFC1 with MEM vitamins (1×) alone, treatment 4, 5, 6 and 7: SOFC1 with MEM vitamins (1×) and 0.5, 1, 1.5 and 2 mM glucose, respectively. The percentage of blastocysts obtained from treatment 6 and 7 (24.7% and 24.8%, respectively) was higher (P < 0.05) than that from treatments 1–5 (14.9%, 9.8%, 16.0%, 14.6%, 14.0%, respectively). Results indicate that glucose (1.5 mM) alone increases the odds of development to the morula stage, but that vitamins must then be present for optimal numbers of embryos to reach the blastocyst stage.