Submitted to: Animal Reproduction Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 22, 2010
Publication Date: March 1, 2012
Citation: Blanco, J.M., Long, J.A., Gee, G., Donoghue, A.M., Wildt, D.E. 2012. Comparative Cryopreservation of Avian Spermatozoa: Effects of Cooling and Thawing Rates on Turkey and Crane Sandhill Sperm Cryosurvival. Animal Reproduction Sciences. 13:1-8. Interpretive Summary: We have used a comparative approach to understand the physiology of sperm survival after cryopreservation. In general, crane sperm survive the freeze/thaw process relatively well, and produce 50-90% fertile eggs after artificial insemination with thawed semen. Conversely, the fertilizing of frozen/thawed turkey sperm is severely compromised after cryopreservation. As a continuation of ongoing comparative research, our objective here was to evaluate the impact of different cooling and thawing rates on the cryosurvival of turkey and crane sperm. We tested rapid, moderate and slow cooling rates, as well as moderate and slow thawing rates. Moderate and slow cooling rates were remarkably superior in preserving sperm viability for both species when compared to rapid cooling; however, slow thawing did not improve viability for either species included in this study. These data are important for developing effective semen cryopreservation protocols for avian species.
Technical Abstract: A comparative approach using Sandhill crane (Grus Canadensis) and the domestic white turkey (Meleagridis gallopavo) was used to determine the possible benefits of variation in cooling and thawing rates and semen volume on cryoprotective efficiency. Sperm was frozen in cryovials using a range of dimethylacetamide (DMA) concentrations from 6-30%. Experiments evaluated the efficacy of (1) rapid, moderate and slow cooling rates, (2) moderate and slow thawing rates, and (3) variation in the final volume of semen frozen. Sperm viability was assessed using the eosin-nigrosin stain. Moderate and slow cooling rates were remarkably superior (p<0.05) in preserving sperm viability in both species when compared to rapid cooling. However, slow thawing did not improve (p>0.05) viability for either species included in this study. Increasing the final volume of crane semen from 20 ul to 120 ul yielded slightly higher viability after thawing. For both turkey and crane sperm, higher DMA concentrations (24-30%) improved the viability of samples post-thaw, when higher DMA concentrations were used. These data further emphasize the need for species specific studies to optimize crypopreservation protocols; in particular, evaluation of cooling rates is important for sperm survival.