Survival and in vitro fertility of boar spermatozoa frozen in the presence of superoxide dismutase and/or catalase

In the present study the potential benefit of reactive oxygen species (ROS)-scavenging enzymes superoxide dismutase (SOD) and catalase (CAT) when cryopreserving boar spermatozoa was evaluated. Pooled ejaculate sperm-rich fractions collected from 3 fertile boars were frozen in a split design, after being extended in a conventional freezing extender (control) or the same extender supplemented with SOD (150 or 300 IU/mL, experiment 1), CAT (200 or 400 IU/mL, experiment 2), or SOD + CAT in combination (150 + 200 or 300 + 400 IU/mL, experiment 3). Irrespective of the concentration used, SOD and CAT, alone or in combination, significantly improved postthaw sperm survival, in terms of total sperm motility (assessed with CASA) and viability (assessed with a triple stain; propidium iodide/R123/fluorescein isothiocyanate-labeled peanut agglutinin). Moreover, CAT alone, at a concentration of 400 IU/mL, or in combination with SOD, at concentrations of 200 and 400 UI/mL, improved the ability of frozen-thawed spermatozoa to produce embryos in vitro (zygote cleavage and blastocyst formation as end points). Additional data of ROS generation (luminol- and lucigenin-dependent chemiluminescence) and membrane lipid peroxidation (malondialdehyde [MDA] production) indicated that SOD and CAT reduced postthaw ROS generation by boar spermatozoa, without any influence on MDA production.