Effects of reduced glutathione on Boer goat semen freezability

Objective: To evaluate the effects of reduced glutathione on the quality of cryopreserved Boer\udbuck spermatozoa. Methods: The current study was carried out on five Boer bucks from which\udsemen samples were collected by artificial vagina. After microscopical evaluation at 37 ℃,\udsemen samples that fulfill the ideal requirements for extension were diluted in a tris–based\udextender including different concentrations of reduced glutathione (2, 5, 7 and 10 mM) and\udthose without glutathione served as a control. Sperm motility, viability, acrosome integrity,\udDNA integrity, total antioxidant capacity and lipid peroxidation were assessed post-thawing.\udResults: The current results revealed that post-thawing motility, viability and acrosomal\udintegrity were significantly improved [(66.67±5.50)%, 168.30±18.59 and (12.75±2.45)%,\udrespectively] when 5 mM glutathione was added to semen extender; especially as compared\udwith the control [(40.00 ±2.88)%, 95.00±8.90 and (25.75±3.46)%, respectively]. Similarly, at\udthis concentration (5 mM) sperm DNA damage, tail length and tail moment of cryopreserved\udsemen were significantly (P<0.05) reduced [(2.32±0.27)%, (1.64±0.49) μm and 3.55±0.63,\udrespectively] compared with the control extender [(6.66±0.84)%, (4.09±0.47) μm and\ud26.47±0.51, respectively]. Moreover, addition of 5 mM glutathione to buck semen extender\udsignificantly (P<0.05) increased total antioxidant capacity [0.51±0.07) mμ/mL] and decreased\udlipid peroxidation of cryopreserved spermatozoa [(8.68±2.72) nmol/mL] compared with the\udcontrol [(0.18±0.02) mμ/mL and (24.92±5.80) nmol/mL, respectively]. Conclusions: The\udaddition of 5 mM glutathione to semen diluent improve freezability of Boer buck spermatozoa\udthrough DNA protection from deterioration and oxidative stress reduction. Moreover, 10 mM\udof glutathione exerts cytotoxic effects on Boer buck semen