Factors impacting equine sperm recovery rate and quality following cushioned centrifugation.

The research explores the impact of different factors such as tube type, centrifugation medium, cushion type, and centrifugation force on the sperm recovery rate and quality in horses post-cushioned centrifugation. The findings suggest that centrifugation in both conventional plastic conical-bottom tubes and new glass nipple-bottom tubes resulted in high sperm recovery and maintained sperm function.

First Experiment

• The first experiment compared sperm recovery rates using conventional plastic conical-bottom tubes and newly developed glass nipple-bottom tubes after cushioned centrifugation. The findings indicated a higher sperm recovery rate in conical-bottom tubes (103%) than in nipple-bottom tubes (96%). However, higher values in terms of semen quality parameters such as total motility, progressive motility, curvilinear velocity, and average-path velocity were observed when centrifugation was performed in the nipple-bottom tubes.
• Additionally, the sperm recovery rate was similar between semen that had been previously diluted in optically clear centrifugation extender and semen diluted in an opaque one, both yielding a 100% recovery rate. However, total and progressive motility were found to be higher in semen subjected to centrifugation in the opaque extender.
• No interaction was observed between the extender and tube type vis-a-vis recovery rate or post-centrifugation semen quality in the first experiment.

Second Experiment

• The second experiment investigated the sperm recovery rate following cushioned centrifugation in nipple-bottom tubes applying forces of 400xg and 600xg. It was observed that the sperm recovery rate was similar at both centrifugation forces (90% in each case), and no differences in semen quality were noticed between the two treatment groups.
• The choice of iodixanol cushion medium used (OptiPrep, Eqcellsire Component B, or Cushion Fluid) did not affect the post-centrifugation semen quality, based on laboratory values measured.

Conclusion

• The findings conclude that cushioned centrifugation in either conical-bottom tubes or nipple-bottom tubes resulted in a high sperm harvest, while preserving sperm function. Therefore, it was found that using an optically opaque extender commonly used in the equine breeding industry can be a viable means to achieve this goal.