Thesis (M.Sc.) - Cairo University - Faculty of Veterinary Medicine - Department of Theriogenology

A total number of 2074 cumulus oocyte complexes (COCs) were aspirated from 1488 ovary collected from a local slaughterhouse (Cairo, Egypt) from January 2014 to October 2015, then COCs, with at least two to three compact layers of cumulus cells and a homogeneous cytoplasm, were selected under a stereomicroscope for the following experiments. Experiment 1, studied the effect of different CPAs and CPAs combinations on maturation of (GV) stage buffalo oocytes in vitro. The maturation rates of (GV) buffalo oocytes were accounted to be (38.10%, 32.00%, 26.51%, 24.07%and 22.00%) after exposure to EG40%, EG20% + GLY20%, EG20% + DMSO20%, EG20% and EG10% CPAs, respectively. Experiment 2, the removal of sucrose from these CPAs solutions has resulted in a significant (P < 0.05) increase in this criteria (59.74%, 51.85% and 40.26%) after exposure to EG20% + DMSO20%, EG20% + GLY20% and EG40%, respectively. Experiment 3, (GV) buffalo oocytes were vitrified after exposure to (20% EG + 20% GLY or 20% EG + 20% DMSO) in straw, open pulled straw or solid surface vitrification system. The highest cleavage and blastocyst rates were obtained in SSV with 20% EG + 20% DMSO group (47.06% and 24.00%, respectively). These values were comparable to those recorded in the control group (61.22% and 46.90%, respectively). Experiment 4, no significant difference was noted between sucrose and trehalose warming media in cleavage and blastocyst rates (44.89% and 20.41% vs. 28.89% and 8.89% respectively). In conclusion, vitrification of buffalo (GV) oocytes using vitrification solutions composed of 20% EG + 20 DMSO without sucrose using SSV, then warming in a stepwise manner using either sucrose or trehalose is the best method for vitrification of (GV) buffalo oocytes

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