The Sperm DNA Damage after Cryopreservation of Boar Semen in Relation to Post-thawed Semen Qualities, Antioxidant Supplementation and Boars Effects

Abstract

The objectives of the present study were to evaluate the damage of DNA of the frozen-thawed (FT) boar spermatozoa and to investigate the effect of various concentrations of L-cysteine supplementation on the sperm DNA damage. A total of 104 cryopreserved semen samples from twenty-six ejaculates of 16 proven boars were analyzed. Of these samples, each semen sample contained a different concentration of L-cysteine i.e., 0 (n=41), 5 (n=41), 10 (n=11) and 15 (n=11) mM. All of the semen samples were cryopreserved by controlled-rate freezer. The semen was thawed at 50oC for 12 sec and the damage to the sperm DNA was determined using acridine orange (AO) staining. The results revealed that, on average, the DNA damage was observed in 0.5% of the FT boar spermatozoa. DNA damage varied among the boars from 0.0% to 4.0%. The levels of DNA damage were 0.6%, 0.4%, 0.5% and 0.9% in the extenders supplemented with 0, 5, 10 and 15 mM of L-cysteine, respectively (p>0.05). In conclusion, the DNA damage of the FT boar spermatozoa was relatively low. No adverse effect of L-cysteine supplementation up to 10 mM on the damage of the sperm DNA was found. Boar characteristic is the most important factor affecting the damage of the sperm DNA.