Developmental competence of Dromedary camel oocytes fertilized in vitro by frozen-thawed ejaculated and epididymal spermatozoa

摘要

The present study aimed to compare the in vitro fertilizing capacity of frozen-thawed ejaculated and epididymal spermatozoa in order to standardize the semen preparation protocol for camel in vitro fertilization (IVF). Semen samples were collected from 7 Dromedary camels by means of artificial vagina (AV). Ten cauda epididymes were obtained from slaughtered adult camels, isolated, incised and rinsed for obtaining the sperm rich fluid. Ejaculated and epididymal spermatozoa were processed for cryopreservation. Fresh and frozen-thawed ejaculated and epididymal spermatozoa were evaluated for motility, livability, membrane and acrosomal integrities. Frozen-thawed ejaculated and epididymal spermatozoa were used to fertilize camel mature oocytes in vitro. The results showed that, the progressive motility of freshly collected epididymal spermatozoa was significantly (P<0.05) higher than ejaculated spermatozoa (49.25 ± 1.75 vs. 38.50 ± 1.50%, respectively). The viability index of epididymal spermatozoa was significantly (P<0.05) higher than that of ejaculated spermatozoa (96.63 ± 2.45 vs. 84.00 ± 4.08, respectively). The post-thaw acrosome and membrane integrities of epididymal spermatozoa were significantly (P<0.05) higher than those of ejaculated spermatozoa. Morula and blastocyst rates of camel oocytes in vitro fertilized by frozen-thawed epididymal spermatozoa (59.4 ± 0.8, 19.12 ± 0.7 and 10.29 ± 0.7%, respectively) were significantly (P<0.05) higher than those fertilized by frozen-thawed ejaculated spermatozoa (48.27 ± 3.1, 11.63 ± 1.1 and 5.43 ± 0.8%, respectively). In conclusion, the Dromedary camel frozen epididymal spermatozoa have the capacity to endure cryopreservation, fertilize oocytes and produce embryos in vitro better than ejaculated sperm.