Lactose-egg yolk diluent supplemented with N-acetyl-d-glucosamine affect acrosome morphology and motility of frozen-thawed boar sperm

These experiments were carried out to investigate the effect of N-acetyl-d-glucosamine, and to obtain additional information about the effect of orvus es paste (OEP) and egg yolk concentration in the freezing of boar sperm in the maxi-straw. The highest post-thaw acrosomes of normal apical ridge (NAR) and motility were obtained with 0.025 or 0.05% N-acetyl-d-glucosamine concentration in the first diluent. However, there were no effects of N-acetyl-d-glucosamine among the diluents with or without N-acetyl-d-glucosamine at the second dilution. The N-acetyl-d-glucosamine in the first and second diluents was added at room temperatures (20–23 °C) and 5 °C, respectively. It is suggested that the temperature of N-acetyl-d-glucosamine addition is important for the effect of boar sperm protection during freezing and thawing. When the 0.05% N-acetyl-d-glucosamine was supplemented in the first diluent, the optimum final OEP content was 0.5%. The optimum content of egg yolk in the diluent with 0.05% N-acetyl-d-glucosamine concentration was 20% and egg yolk was one of the main cryoprotective agents. In conclusion, we found out that the diluent with 0.025 or 0.05% soluble N-acetyl-d-glucosamine in the first diluent, 0.5% final orvus es paste concentration and 20% egg yolk concentration significantly enhanced NAR acrosomes and motility of boar sperm after freezing and thawing.