Effect of Maca aqueous extract addition to a freezing extender for canine semen.

This study investigated the effect of the addition of Lepidium meyenii (Maca) to the freezing extender on the post-thaw quality of dog semen. Ten canine ejaculates were frozen following a two-step protocol using a tris-glucose-citrate egg yolk extender with or without the addition of 10 µl/mL of aqueous extract of Maca (Maca and ctrl groups, respectively). Prior to (fresh semen) and after freezing (T0) sperm motility, kinetic parameters, viability and mitochondrial membrane potential (MMP), as well as the levels of malondialdehyde (MDA) were evaluated. In addition, sperm motility, kinetic parameters, viability and MMP were examined up to 2 h of incubation of 37 °C after thawing (T1 and T2) to evaluate thermo-resistance. The addition of Maca reduced MDA concentration at T0 (p < 0.05) and increased total motility, the percentage of sperm with medium velocity and WOB at T1. Progressive motility decreased (p < 0.05) at T1 in the ctrl group, whereas it was not affected in Maca group at any time point. In addition, the percentage of hyperactivated spermatozoa remained constant at T1 in the ctrl, while in the Maca group an increase (p < 0.05) of this parameter was recorded. Although no differences were found for MMP between groups at any time points, a decrease of viable sperm with low MMP was observed in ctrl group between T0 and T1 and in Maca group between T1 and T2. The addition of Maca prior freezing reduced the extent of lipid peroxidation and activated canine sperm motility and hyperactivation after thawing.