Effects of reduced glutathione on the quality of rooster sperm during cryopreservation

Abstract

The purpose of this study was to investigate the beneficial effects of reduced glutathione (GSH) for cryopreservation of rooster semen. In experiment 1, semen samples were collected from 15 roosters and diluted in the Lake extender that contained various concentrations of GSH as follows: Lake without GSH (control, GSH 0), Lake containing 0.5 mM (GSH 0.5), 1 mM (GSH 1), 2 mM (GSH 2), 4 mM (GSH 4) and 8 mM (GSH 8) GSH. Viability, membrane functionality, morphology, mitochondrial activity, acrosome integrity, motion parameters, lipid peroxidation and DNA fragmentation were assessed after thawing. In experiment 2, reproductive performance of thawed semen was evaluated via artificial insemination. Supplemented extenders with 2 and 4 mM GSH presented higher (P ≤ 0.05) viability (59.4 ± 2.4% and 60.8 ± 2.4%), membrane functionality (62.3 ± 2.6% and 64.7 ± 2.6%), mitochondrial activity (49.4 ± 1.7% and 49.8 ± 1.7%), total motility (57.1 ± 1.9% and 58.8 ± 1.9%, respectively), progressive motility (28.9 ± 1.3% and 29.6 ± 1.3%), and lower lipid peroxidation (2.4 ± 0.09 nmol/ml and 2.3 ± 0.09 nmol/ml) compared to control group. Acrosome integrity was higher (P ≤ 0.05) in GSH 4 (91.4 ± 1.8%) compared to other groups. DNA fragmentation and MDA concentrations were higher (P ≤ 0.05) in GSH 8 (12 ± 1.2% and 3.4 ± 0.09 nmol/ml). In experiment 2, higher (P ≤ 0.05) fertility rate was observed in GSH 2 and GSH 4 (61.9% and 63.8%, respectively) compared to control (41.4%) group. In conclusion, supplementation of Lake extender with 2 and 4 mM GSH improves the cryo-survival and fertility potential of rooster sperm and it could be an applied method for improvement of reproductive goals.