Effect of two extenders on fertility of mares inseminated with jackass semen diluted and cooled at 5°C for 12 hours

Abstract

concentration as the first half. Spermwas then stored at 4 C for 24hours. Immediately prior to cooling and after 24hours of storage at 4 C, spermwas analyzed for kinetic and quality parameters: total motility (MT) and average path velocity (VAP) were assessed by Computer Assisted Sperm Analysis IVOS, membrane integrity (IM) was evaluated using NucleoCounter SP-100, and DNA integrity (expressed as DNA fragmentation index, DFI) was evaluated by Sperm Chromatin Structure Assay (SCSA) [1]. The Wilcoxon matched pairs test was used to evaluate the effect of seminal plasma on MT, VAP, IM, and DFI. Prior to storage, 50% seminal plasma had no effect on total motility, DNA and membrane integrity, when compared with samples containing 0% plasma; however, the presence of 50% plasma significantly (P < 0.01) increased average path velocity. After 24 hours of storage at 4 C, spermwith 0% seminal plasma showedbetter DNA quality (lower % DFI, P < 0.001), higher values of membrane integrity (P < 0.05) and total motility (P < 0.01) as compared to sperm stored with 50% seminal plasma, but no differences were found for average path velocity. During cooled storage, samples with 0% seminal plasma showed no changes with respect to kinetic and quality parameters, while a significant (P < 0.01) worsening of DNA integrity, totalmotility andmembrane integritywas evidenced for the samples extended in 50% seminal plasma after 24 hours at 4 C. In conclusion, the complete removal of seminal plasma during cooled semen storage was protective to sperm quality, while the presence of seminal plasma was associated with an increasing of sperm DNA damage and alteration of membrane stability after 24 hours storage at 4 C.