Study of different levels of Vitamin A supplementation in extender on sperm quality in cooling storing and cryopreservation condition in Ghezel ram

This study aimed to investigate the protective effects of different levels of vitamin A on ram sperm diluent during storage until equilibrium and before cryopreservation at 4 °C and freeze-thawing.

In this study, 4 Ghezel rams were used for semen collection by the artificial vagina. After the initial evaluation, the samples with normal properties were pooled and after the dilution process, 0, 5, 15, and 20 µmol vitamin A were added to the samples and frozen after 2 hours of cooling. Parameters of motility, viability, plasma membrane integrity, and sperm morphology were evaluated in two steps (before and after cryopreservation) as well as malondialdehyde levels after freeze-thawing.

The results showed that the addition of different levels of vitamin A to the extender during cooling at 4 °C had no significant effect on the evaluated parameters (P <0.05). The results after freezing showed that a level of 15 µmol of vitamin A increased the total motility, progressive motility (PM), VAP, and VSL (P <0.05). Plasma membrane integrity and viability increased significantly at the level of 15 µmol and also adding 15 µmol levels to the freezing medium decreased the amount of sperm with abnormal morphology and the amount of malondialdehyde compared to the control group (P <0.05).

According to the results of adding different levels of vitamin A, the level of 15 µmol has the best performance in improving the evaluated parameters and reduces oxidative stress during cryopreservation and thawing.