The Effect of Cryopreservation Temperature and Time on Viability and In Vitro Maturation of Sheep Oocytes | ||||
| Journal of Animal and Poultry Production | ||||
| Article 3, Volume 12, Issue 2, February 2021, Page 79-83 PDF (600.95 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2021.62680.1010 | ||||
 View on SCiNiTO | ||||
| Author | ||||
Ehab Salah Abdel-Aal 
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| Animal production, faculty of Agriculture , Cairo university | ||||
| Abstract | ||||
| This study aim to compare the effects of freezing techniques on viability and in vitro maturation of sheep oocytes. This experiment was carried out in Animal Production Research Institute. Sheep ovaries were obtained from slaughterhouse. A total of 695 oocytes were used in this study, 114 oocytes as control and 581 were exposed to LN2 vapor then divided into 3 groups: G1(190); directly plunged into LN2, G2 (198): cryopreserved in ˗80 oC freezer and, G3 (193), plunged into LN2 for 10 min and then transferred to –80 oC freezer. Oocytes in each group were cryopreserved for (24h, and 7days). There were high significantly differences (P<0.01) between the percentage of damage for cryopreserved oocytes, where zona dissolution was the main damage for (G1and G3) oocytes. Whereas, zona rupture was the highest damage occurred in (G2) oocytes. Survival rate of G1 oocyte was higher significantly (P<0.05) than G3 and G2, the same results were obtained pattern, either after 24h or 7 days storage. Highly significant differences (P<0.01) between maturation rate achieved with the control oocytes (63%) compared with the other groups. After 24 h of storage, G1 recorded higher MII rate followed by G3 and G2 (47, 37 and 28%, respectively), MII % decreased at 7 days storage in G1, G3 and G2 (44%, 34% and 31%, respectively). In conclusion, Cryopreservation of sheep oocytes (G3) in –80 °C freezer achieved acceptable survival and in vitro maturation rates. The –80°C freezer provide a simple and cheap tool to maintain frozen sheep oocytes. | ||||
| Keywords | ||||
| Ewes - Oocyte - cryopreservation- storage time; IVM | ||||
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