In the present study, we examined the effect of different lecithin concentrations on spermatozoa characteristics after freeze-thawing. Hanwoo semen was collected from one bull and divided into five groups (tris-citric acid semen extender with 0, 0.1, 0.25, and 0.5% lecithin groups as well as a 20% egg yolk group). Semen extender with 20% egg yolk was used as control treatment. After the freeze-thawing of semen, spermatozoa motility, motility parameters, viability, acrosomal membrane integrity, mitochondrial membrane potential, and plasma membrane integrity were examined. In experiment 1, the effect of different lecithin concentrations on spermatozoa motility and associated parameters was examined. The 0.1% lecithin-treated spermatozoa showed greater fast progressive motility (%) in addition to higher VCL (μm/s), VSL (μm/s), and VAP (μm/s) when compared to other lecithin concentration groups and controls. In experiment 2, the effect of different lecithin concentrations on spermatozoa viability was examined. The 0.1% and 0.25% lecithin addition groups (55.4±7.3 and 51.7±11.2%) exhibited similar viability compared to the control group (54.1±12.6%). In experiment 3, the effects of different lecithin concentrations on viability, acrosomal membrane integrity, and mitochondrial membrane integrity of spermatozoa were examined. The percentage of live spermatozoa with an intact acrosome and high mitochondrial membrane potential in the 0.1% lecithin group was not significantly different compared to the control group (31.2±13.3 vs. 30.5±10.9%). In experiment 4, the effect of different lecithin concentrations on the plasma membrane integrity of spermatozoa was examined. The percentage of spermatozoa with a normal plasma membrane was similar between the 0.1% lecithin and control groups (31.2±13.3 vs. 30.5±10.9%). In conclusion, we suggest that semen extender supplemented with 0.1% lecithin can replace 20% egg yolk without reducing spermatozoa quality.

Abstract
Introduction
Materials and Methods
    1. Semen collection, freezing, and thawing
    2. Examination of spermatozoa motility andassociated parameters after freeze-thawing
    3. Examination of spermatozoa viability afterfreeze-thawing
    4. Examination of viability, acrosomal membraneintegrity, and mitochondrial membrane potentialof frozen-thawed spermatozoa
    5. Evaluation of spermatozoa plasma membraneintegrity after freeze-thawing
    6. Statistical analysis
Results and Discussion
References

• Sung-Sik Kang(Hanwoo Research Institute, National Institute Animal Science, Rural Development Administration)
• Ui-Hyung Kim(Hanwoo Research Institute, National Institute Animal Science, Rural Development Administration)
• Kyung-Woon Kim(Hanwoo Research Institute, National Institute Animal Science, Rural Development Administration)
• Sang-Rae Cho(Hanwoo Research Institute, National Institute Animal Science, Rural Development Administration) Corresponding author