Comparison of extracted low-density lipoproteins from egg yolk with lecithin, and commercially extender “Andromed” in bull's semen freezability

Biochemical and anatomical structures of sperm cell are affected during the freezing process. Therefore, using of cryoprotectant in freezing extender is the most essential part of the sperm freezing process. The aim of this study was to evaluate the effect of different levels of low-density lipoprotein (6, 8 and 10 percent) and different levels of soy lecithin as cryoprotectant compared to the Andromed commercial extender on freezing-thawing of Holstein bull Sperm. In this study, semen was collected from three Holstein bull using artificial vagina twice a week.In order to eliminate the effects of individual animals, ejaculations were pooled in equal proportions. After cooling and filling of extended semen samples in straw, were frozen and stored in liquid nitrogen. Results showed that there are no significant differences among LDL and soybean lecithin levels as well in terms of evaluated parameters. Using of Andromed extender significantly improved kinetics, motility, viability and plasma membrane integrity parameters of sperm cells at different levels of LDL (P < 0.05). Progressive motility at the levels of 1, 1.5 and 2 percent of lecithin was significantly lower than Andromed. No significant difference was observed in the viability and plasma membrane integrity of sperms in the different levels of lecithin and Andromed extender. In general, the extender containing 3% soy lecithin had similar results with commercial extender of Andromed.