Post-thaw quality of boar spermatozoa is affected by ejaculate fractions and extenders

The aim of this study was to investigate the effect of different extenders on the post-thaw (PT) quality of sperm originating from the sperm-rich fraction (SRF) and post-sperm-rich fraction (PSRF) of boar ejaculate. Motility and velocity parameters, analyzed using a computer-assisted semen analysis (CASA) system, and membrane integrity parameters were markedly higher in frozen-thawed (FT) spermatozoa of the SRF in both the Belstville Thawing Solution (BTS) and Androhep Plus (AHP) extenders, irrespective of the post-thaw (PT) storage time. Furthermore, reduced cryo-survival was more marked in FT spermatozoa of the PSRF in both extenders following storage for 60 min. It was found that the SRF-stored samples in the AHP extender for 60 min exhibited significantly higher percentages of spermatozoa with total motility, mitochondrial function and acrosome integrity than those stored in the BTS extender. The findings of this study confirm that components of the ejaculate fractions and extender have varying effects on the cryo-survival of boar spermatozoa.