Effect of Soybean lecithin-based Extender on Sperms Motility in the Chilled and Frozen Semen of Nubian bucks

Abstract

This study was conducted to investigate the effect of different concentrations of soybean lecithin extenders on motility of sperms in the chilled and frozen semen of Nubian bucks. A total of 59 ejaculates were collected from 6 fertile bucks once a week during 9 weeks interval using artificial vagina. After initial evaluation of ejaculates, the semen samples were divided into three equal groups and diluted at 1:5 (semen: extender) using extenders containing 2% egg yolk with tris –citric acid (TCEY, control group, n= 59), 3% soybean lecithin with tris-citric acid (TCSL 3%, n=59) and 4% soybean lecithin with tris-citric acid (TCSL 4%, n=59).The motility rates of spermatozoa after equilibration period at 5ºC for one and 4 hours; and after freezing at -196 ºC for 30 days were recorded.The results indicated that there were no significant differences in motility rates among the deferent concentrations of TCSL and TCEY at temperature 5 ºC for 1 (very good motile: 80-100%) and 4 (good motile: 60-79%) hours. Overall mean of sperm motility rates was lower after cooling for 4 hours than 1 hour. The motility values of post-thawed semen containing TCSL 3% after cryopreservation at -196 ºC for 30 days were significantly higher (66.36 ± 10.3 %) than those containing TCSL 4% (60.34 ±11.9 %) (p<0.05). However, there were no significant differences between motility rates of frozen semen diluted with TCSL and TCEY. It could be concluded that soybean lecithin 3% provided the best motility of frozen-stored spermatozoa than soybean lecithin 4% and egg yolk.