Effect of cushioned or single layer semen centrifugation before sex sorting on frozen stallion semen quality.

The study explores and compares the effects of cushioned centrifugation (CC), single-layer colloid centrifugation (SLC), and simple dilution (SD) on stallion semen quality, pre and post sex sorting, and post thawing and freezing, with the results indicating that both CC and SLC are unable to effectively select those spermatozoa that display better resilience to sperm sorting and freezing processes.

Objective of the Research

The main objective of the study was to compare the impact of different methods of presorting centrifugation – cushioned centrifugation (CC), and single-layer colloid centrifugation (SLC), along with simple dilution (SD) – on the quality of sex-sorted stallion semen. The researchers gauged semen quality through multiple criteria such as sperm motility, viability, acrosome integrity, and level of DNA fragmentation.

Methodology and Results

• The examination incorporated four semen samples from each of two fertile stallions, collected every week. Total sperm motility (TM), percent of viable and acrosome-intact sperm (VAI), and DNA quality were assessed.
• The results indicated a significant drop in TM and VAI after freezing, regardless of the presorting treatments (CC and SLC).
• Notably, sorting did not have a negative effect on TM and VAI. On the contrary, sorting had a positive impact on DNA quality across all treatments before freezing. However, these beneficial effects were lost after freezing and thawing.

Conclusions and Implications

• The results pointed towards the conclusion that the freezing process reduces the DNA quality of sex-sorted sperm. Therefore, techniques employing freezing must be reconsidered or adjusted to prevent DNA quality degradation.
• Importantly, both CC and SLC methods of semen centrifugation failed to select those sperms that demonstrate a better ability to withstand the process associated with sperm sorting and freezing. This finding assimilates new knowledge into existing reproductive technologies.