Effect of glycyrrhizic acid on lipid peroxidation and vital parameters of Holstein bull sperm after freeze-thawing process

To examine the effect of glycyrrhizic acid on lipid peroxidation and vital parameters of Holstein bull sperm after freeze-thawing process, semen samples were collected from four mature Holstein bulls twice a week using artificial vagina. Ejaculates were pooled in order to eliminate the individual effects of bull. Semen samples were divided into four equal groups (8 reps) including Zero (control), 20, 30 and 40 mg/ml of glycyrrhizic acid along with diluents based on egg yolk-citrate. Following cooling and equilibration stage, semen samples were stored in nitrogen tank for 30 days. After thawing procedure, level of malondialdehyde in sperm samples were measured by ELISA. Also, membrane integrity, motility and viability of sperm were examined. Statistical analysis was carried out using one-way ANOVA and post-hoc Tukey tests (p<0.05). According to the results, membrane integrity, motility and viability of sperm samples treated with concentration of 20, 30 and 40 mg/ml glycyrrhizic acid dose dependent manner significantly increased and level of malondialdehyde dose dependent manner significantly decreased ccompared to control groups (p<0.05). Therefore, use of glycyrrhizic acid in bull semen diluent can improve sperm vital parameters and decreases lipid peroxidation of sperm after freeze-thawing process.