Abstract
The present study aimed to assess the freezability and functional integrity of dromedary camel spermatozoa harvested from three epididymal regions. Twenty five epididymes were obtained from slaughtered adult camels. The cauda, corpus and caput epididymides were isolated, incised and rinsed for obtaining the sperm rich fluid. Portion of this fluid was processed for cryopreservation. Fresh and frozen-thawed spermatozoa collected from different epididymal regions were evaluated for motility, livability, morphological abnormalities, membrane and acrosomal integrities as well as mitochondrial activity. Also, in vitro fertilization using camel mature oocytes and measuring DNA integrity using Comet assay were performed for these spermatozoa. The results showed that, there were no significant differences in livability among spermatozoa freshly collected from cauda, corpus and caput epididymides (81.16 ± 1.43, 80.20 ± 0.90 and 76.76 ± 1.95%, respectively). Total sperm motility increased dramatically from the caput (22.60 ± 0.96%) to the cauda (67.92 ± 1.14%) of the epididymis. Viability index of cauda frozen-thawed spermatozoa (96.50 ± 2.36%) was significantly higher than those of corpus (53.20 ± 3.11%) and caput epididymides (12.10 ± 1.10%). Fresh and frozen thawed spermatozoa of the cauda epididymides had significantly higher percentages of membrane integrity, cytoplasmic droplets and MTT reduction rate than the corresponding parameters of corpus and caput spermatozoa. Fresh and frozen thawed spermatozoa of the cauda epididymides had significantly higher fertilization rates (50.88 ± 1.10 and 38.64 ± 0.77%, respectively) than those of corpus (36.92 ± 0.79 and 22.16 ± 0.79%, respectively) and caput epididymides (12.48 ± 1.09 and 4.36 ± 0.59%, respectively). Only oocytes fertilized with fresh and frozen-thawed cauda epididymal spermatozoa developed to blastocysts (10.92 ± 0.52 and 8.12 ± 0.81%, respectively). The percentage of fresh cauda epididymal spermatozoa with non-fragmented DNA was higher than those of corpus and caput of epididymis (90.88 ± 1.55 vs. 78.28 ± 0.72 and 76.24 ± 1.02%, respectively). In conclusion, obtaining spermatozoa of good quality and freezability from dromedary camel cauda epididymides is possible, and these fresh and frozen-thawed spermatozoa may have the potential uses in IVF and AI for improving breeding potentials in this species.

Key words: camel – epididymis – spermatozoa –cryopreservation – IVF – comet