| Autor: |
Y.X. Hu, S.A. Voelkel |
| Rok vydání: |
1992 |
| Předmět: |
|
| Zdroj: |
Theriogenology. 37:23-37 |
| ISSN: |
0093-691X |
| DOI: |
10.1016/0093-691x(92)90245-m |
| Popis: |
The ability to transfer frozen embryos directly to recipient females after thawing would be a convenience in embryo transfer and would facilitate marketing embryos produced in large quantities by in vitro procedures. Techniques for direct transfer of bovine embryos use sucrose as an osmotic buffer to remove glycerol while the embryo is in the straw prior to transfer or use sucrose added to the cryoprotectant solution allowing transfer without additional steps. These methods are reviewed as well as a new approach to freezing embryos for direct transfer. The new procedure for direct transfer of frozen embryos uses 1.5 M ethylene glycol as a cryoprotectant. Embryos frozen in ethylene glycol can be rehydrated directly in holding medium without step-wise dilution of the cryoprotectant yielding viability equivalent to that of embryos frozen in glycerol and rehydrated in a step-wise manner. In addition, the pregnancy rate for nonsurgically recovered embryos frozen in 1.5 M ethylene glycol in straws containing additional columns of holding medium, thawed and transferred directly to recipients (50%) was comparable to the pregnancy rate for embryos frozen in glycerol and rehydrated using a step-wise procedure prior to transfer. Ethylene glycol can be used effectively as a cryoprotectant for bovine embryos permitting thawed embryos to be rehydrated directly in holding medium or transferred directly to recipients. Identifying effective cryoprotectants to which bovine embryos are highly permeable is an alternative approach for developing direct transfer procedures. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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