Cushioned and Single Layer Centrifugation Improve Epididymal Stallion Sperm Motility Postcentrifugation

Abstract

Traumatic injuries and sudden death can prematurely end the breeding career of a stallion. In such cases, a final spermatozoa collection can be obtained by harvesting the cauda epididymis. Semen samples can then be used for fresh artificial insemination or cryopreserved. Centrifugation is a critical point of sperm cryopreservation processing and can be detrimental to spermatozoa. Colloid centrifugation approaches reduce this physical damage and can be used to select better quality sperm. The aim of this research was to determine the effect of cushioned and single layer centrifugation (SLC) on epididymal stallion sperm motility postcentrifugation. Eight stallions were submitted to bilateral orchiectomy and the resulting epididymal cauda (n = 16) were flushed with semen extender. After harvesting, the samples were submitted to three centrifugation protocols: conventional (20 minutes at 600×g), cushioned (20 minutes at 900×g), and SLC (20 minutes at 300×g). The pellets were resuspended and sperm parameters were evaluated. Sperm morphology was evaluated under a phase-contrast microscope, total motility (TM) and progressive motility (PM) were evaluated with computer-assisted semen analyses. The proportion of morphologically normal spermatozoa was 72.2% for SLC, 72% for cushioned, and 67% for conventional (P > .05). After conventional centrifugation, it was recorded a TM of 7.4% and PM of 2.7%. After cushioned centrifugation, it was recorded a TM of 13.9% and PM of 6.5%. After SLC, it was recorded a TM of 46% and PM of 32.1%. The motility of spermatozoa recovered by SLC (P < .05) and cushioned centrifugation (P > .05) were higher than those recovered by conventional centrifugation. Colloids, including cushioned and SLC, improved epididymal stallion sperm motility postcentrifugation.