Effect of Aqueous Extract of Maca Addition to an Extender for Chilled Canine Semen

Abstract

Antioxidant supplementation has been proposed as a new strategy to improve the long-term preservation of semen. The aim of this study was to evaluate the effect of Maca supplementation of semen extender on quality-related canine semen parameters during cooling. Ejaculates from nine dogs were cooled for 7 days in the absence (control group) or in the presence of 10, 20 and 50 μL/mL of an aqueous extract of Maca. Sperm were evaluated for sperm viability, motility, DNA fragmentation and lipid peroxidation after 3 h, 24 h, 4 days and 7 days of storage. The addition of 10 μL/mL of Maca preserved sperm DNA and plasma membrane integrity at 3 h and increased sperm curvilinear velocity after 24 h. Treatment with 20 and 50 μL/mL of Maca increased the percentage of hyperactivated sperm after 3 h. Moreover, semen treated with 20 μL/mL of Maca decreased lipid peroxidation at 24 h. A significant reduction of sperm DNA and plasma membrane integrity as well as of kinetics parameters between 3 and 24 h of refrigerated storage with the higher concentration tested was observed. Although Maca was not able to protect canine semen with extended refrigeration storage time, it increased hyperactivation and preserved DNA integrity in short-term storage.

Keywords: Lepidium meyenii; antioxidant; canine spermatozoa; semen cooling; sperm hyperactivation.

Figure 1

Total (A) and progressive motility (B) of dog semen (n = 9) diluted with only egg-yolk tris-citrate glucose (YET-G; CTRL) or with EYT-G with the addition of three different concentrations (10, 20 and 50 μL/mL) of aqueous extract of Maca (M10, M20 and M50) stored at refrigeration temperature (4 °C) and evaluated at 3 h, 24 h, 4 d and 7 d of storage. Asterisk above the bar indicates statistical difference between groups at p ≤ 0.05. The letters a, b and c indicate statistically significant differences at p ≤ 0.05 between time points within each group.

Figure 2

Percentage of DNA fragmentation (A) and lipid peroxidation (B) of dog semen (n = 9) diluted with only egg−yolk tris−citrate glucose (EYT−G; CTRL) or with EYT−G with the addition of three different concentrations (10, 20 and 50 μL/mL) of aqueous extract of Maca (M10, M20 and M50) stored at refrigeration temperature (4 °C) and evaluated at 3 h, 24 h, 4 d and 7 d of storage. Asterisk above the bar indicates statistical difference between groups at p ≤ 0.05. The letters a, b, c and d indicate statistically significant differences at p ≤ 0.05 between time points within each group.