Effect of Semen Extender on Crypreservation and Fertilization Rates of Dromedary Camel Epididymal Spermatozoa

The last decade showed great interest in the application of assisted reproductive technologies in camel reproduction particularly in racing and milking animals which represent part of the Arab heritage. The present work was designed to assessthe cryopreservation and fertilization rates of dromedary camel epididymal spermatozoa using different extenders. In experiment 1: 16 testicles from mature dromedary camel were collected at Cairo slaughterhouse, transported to the lab at 4 °C. Spermatozoa were extracted from epididymides using the retrograde flushing technique, washing sperm cells in a retrograde direction from the ductus deferens through the caudaepididymidis with a syringe loaded with warmed (37°C) extender .Retrievedepididymal spermatozoa were diluted in Ovixcell®, in Tris-fructose-egg yolk and sodium citrate-egg yolk semen extenders. Spermmotility was evaluated after 15 minute of incubation in a water bath at 37°C under phase-contrast microscopy using a pre-warmed (37°C) Makler Chamber. In experiment 2: epididymal spermatozoa extended in Ovixcell and tris-fructose-egg yolk was processed for freezing and stored in liquid nitrogen at - 196 ºC. Sperm Post-thawing motility was evaluated after 15 minute of incubation in a water bath at 37°C under phasecontrast microscopy using a pre-warmed (37°C) Makler Chamber. Epididymal spermatozoa were used for in vitro fertilization of in vitro matured camel oocytes. Cleavage rate and development to the blastocyst stage were determined. Initial epididymal sperm motility was 52.8 ± 0.7%, 41.2 ± 33.7% and 7.5± 2.5% for Ovixcell®, Tris-fructose-egg yolk semen extender and sodium citrate-egg yolk, respectively. Post thawing motility was similar in Ovixcell® and tris-fructose-egg yolk extenders (47.5± 5.0% and 45.0 ± 7.5%, respectively. Also, cleavage rate was similar for in vitro mature dromedary oocytes fertilized by frozen thawed epididymal spermatozoa extended in Ovixcell® orTris-fructose-egg yolk semen extenders (79.3 and 83.8%, respectively. Morulae and blastocyst rates were 58.1% and 52.2 for spermatozoa cryopreserved inOvixcell®, Tris-fructose-egg yolk semen extender, respectively. In conclusion, Ovixcell®, Tris-fructose-egg yolk semen extenders are suitable to use in cryopreservation and in in vitro fertilization of camel epididymal spermatozoa.