The effect of green tea extract supplementation in bull semen cryopreservation

Abstract

This study aims to investigate the effect of catechin (CT), green tea extract, as a supplement to Tris extender on semen quality parameters in frozen-thawed of bull sperm. Ejaculates were taken with artificial vagina from Holstein bulls and divided equal five aliquots, diluted to containing different amounts of CT (5, 10, 25 and 50 μg/mL) and no-additive (control). All samples were equilibrated at 4°C for 4 h and were frozen using a digital freezing machine. Post-thawed sperm motility and kinetic parameters were determined using the sperm analyser system. Spermatozoa DNA integrity was evaluated with the single cell gel electrophoresis, abnormal spermatozoa rate was evaluated by fluid fixation test and lipid peroxidation status was evaluated colorimetrically. CT supplementation did not improve motility and kinetic parameters. However, the higher morphological integrity was detected in CT10, 25 and 50 groups compared to control (P<0.05). Regarding chromatin integrity, positive effects of catechin were observed in the treatment groups while in CT 50 group adverse effects were found (P<0.05). Although there was no improvement in malondialdehyde levels, the highest total antioxidant activity was seen in the CT50 group (P<0.05). In conclusion, CT supplementation could be used the protection of morphological and DNA integrity from cryodamage and it has increased the total antioxidant activity depending of the dose in bull semen.