Enzymatic Antioxidant Activity of Stallion Spermatozoa Cryopreserved With Extenders Containing Glutamine And Proline

Considering the role of amino acids glutamine and proline as antioxidant in improving the post-thaw motility of stallion spermatozoa, the present study was carried out to investigate the possible effects of glutamine and proline in the composition of freezing extender on MDA concentration as an indice of lipid peroxidation as well as activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPX) of equine semen during cryopreservation. Ten ejaculates from five fertile stallions collected by artificial vagina, were frozen in basal medium (INRA82) as control (E1) and basal medium containing 3mM proline (E2) and 5mM glutamine (E3). The biochemical assays were performed after thawing. The results showed that MDA, GPX and SOD remained unchanged with different extenders, but CAT activity significantly increased in E3 group (p<0.05). In the present study, increase of catalase enzyme in the presence of 5mM glutamine together with no effect on preventing MDA formation and trace decline in some post-thawe motion parameters show that cryodamages leading to a decline in motility parameters of stallion spermatozoa examined in this study are irrelevant of oxidative stress. Our study revealed that inclusion of glutamine and proline in freezing extender resulted in no effect on enzymatic antioxidantstatus and lacked toxic effects, but were ineffective in cryopreservation of stallion spermatozoa as well. Thus, it seems that oxidative stress might play a minor role in frozen stallion semen with high sperm quality and motility.

Keywords:

Glutamine , Proline , Post-Thawed , Stallion Sperm , Antioxidant Activity