ABSTRACT
The aim of this study was to evaluate the effect of supplementing bovine semen freezing extender with different concentrations of iodixanol on post-thaw sperm characteristics. Six ejaculates of three Nellore bulls were pooled and diluted in commercial extender (BotuBov®) and then divided into 4 groups: control group (without adding iodixanol); groups G1.5, G3, or G6 according to the concentration of iodixanol solution (RedCushion®). After dilution, the samples were cooled and frozen. Post-thaw semen evaluation included sperm motility by CASA immediately after thawing and after 60 min of incubation at 37°C, flow cytometry analysis for integrity of plasma and acrosomal membranes, membrane destabilization and translocation of phosphatidylserine, mitochondrial membrane potential, and formation of intracellular anion superoxide ( O 2 - ), hydrogen peroxide (H2 O2 ), and membrane lipid peroxidation. The group G6 presented significantly higher (p < .05) total and progressive motility, percentage of plasma and acrosomal membrane integrity, and H2 O2 than control and group G1.5. Furthermore, group G6 showed lower (p < .05) lipid peroxidation than control. In addition, regardless of the concentration used, the percentage of spermatozoa without phosphatidylserine translocation was higher (p < .05) in all iodixanol supplemented groups. In conclusion, iodixanol supplementation preserved the motility and integrity of sperm membranes during cryopreservation and protected against lipid peroxidation.
