Use of a Single-Layer Density Centrifugation Method Enhances Sperm Quality in Cryopreserved-Thawed Equine Spermatozoa

The objective of this study was to improve the quality of cryopreserved-thawed equine sperm using single-layer density centrifugation (SLC). Sperm quality was assessed by DNA integrity, motility, morphology, mitochondrial membrane potential, viability, and plasma membrane alteration. The percentage of DNA-damaged sperm (expressed in % COMP) was lower (P = .001) after SLC (1.6 +/- 0.5% vs. 6.8 +/- 0.5%). Total sperm motility (80 +/- 2.4% vs. 41.7 +/- 2.4%) and progressive sperm motility (69.5 +/- 2.9% vs. 31.5 +/- 2.9%) (P < .001), as well as the percentage of morphologically normal sperm (45 +/- 3.9% vs. 27.7 +/- 3.9%), increased after SLC compared with control sample. In addition, the proportion of sperm with high mitochondrial membrane potential increased (81.6 +/- 1.8% vs. 42.1 +/- 1.8%), as did the viability of sperm (71.1 +/- 2.4% vs. 39.5 +/- 2.4%), after SLC compared with the control sperm. The proportion of sperm with alteration in plasma membrane structure was lower after SLC compared with control sample (6.4 +/- 1.1% vs. 18.9 +/- 1.1%). Overall, sperm recovery was 72.+/- 7 3.6% in the control sample compared with 14.8 +/- 3.6% after SLC (P < .001). We conclude that based on the sperm parameters evaluated, SLC improves the quality of cryopreserved-thawed equine spermatozoa. (C) 2013 Elsevier Inc. All rights reserved.