Effects of Seminal Plasma on Frozen-thawed Stallion Epididymal Semen Plasma Membrane Integrity

Frozen-thawed epididymal sperm of stallions has variable post-thaw motility. Epididymal sperm are collected postmortem or postcastration and therefore are not exposed to the effects of seminal plasma as is ejaculated semen. The objective of this study was to evaluate the effects of seminal plasma plus extender versus extender or seminal plasma alone on epididymal spermatozoa plasma membrane integrity using the hypoosmotic swelling test (HOST). Our hypothesis was that epididymal sperm exposed to seminal plasma would demonstrate better post-thaw membrane integrity as assessed by HOST than epididymal sperm frozen without exposure to seminal plasma. [...]