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

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

Improvement of vitrification of in vitro produced buffalo embryos with special reference to sex ratio following vitrification

Cryopreservation and sexing of embryos are integrated into commercial embryo transfer technologies. To improve the effectiveness of vitrification of in vitro produced buffalo embryos, two experiments were conducted. The first evaluated the effect of exposure time [2 and 3 min] and developmental stage [morula and blastocysts] on the viability and development of vitrified buffalo embryos. Morphologically normal embryos and survival rates [re-expansion] significantly increased when vitrified morulae were exposed for 2 min compared to 3 min [P<0.001]. On the other hand, morphologically normal and survival rates of blastocysts significantly increased when exposed for 3 min compared to 2 min [P<0.001]. However, there were no significant differences between the two developmental stages [morulae and blastocystes] in the percentages of morphologically normal embryos and reexpansion rates after a 24 h culture. The second experiment aimed to evaluate the effect of viability on the sex ratio of buffalo embryos after vitrification and whether male and female embryos survived vitrification differently. A total number of 61 blastocysts were vitrified for 3 min with the same cryoprotectant as experiment 1. Higher percentages of males were recorded for live as compared to dead embryos; however, this difference was not significant. In conclusion, the post-thaw survival and development of in vitro produced morulae and blastocysts were found to be affected by exposure time rather than developmental stage. Survivability had no significant effect on the sex ratio of vitrified blastocysts; nevertheless, the number of surviving males was higher than dead male embryos