Characteristics and in vitro fertilization ability of cauda epididymal and ejaculated ram sperm

Abstract

The characteristic and in vitro fertilization ability of ram spermatozoa collected from cauda epididymides was axamined. Ejaculated spermatozoa was used as control group in this experiment. Characteristic of spermatozoa including of percentage of progressive motility, viability, abnormalities and membrane integrity were evaluated before and after freezing. Fertilization ability of postthawed of the spermatozoa in both group was examined based on the pronucleus formation after in vitro fertilization of in vitro matured (IVM) oocytes. Results from these study showed that there were no significant differences in the characteristics between cauda epididymal and ejaculated spermatozoa before freezing (P>0.05). After freezing, motility of ejaculated spermatozoa was higher than epididymal spermatozoa (54.00±2.24% vs 48.00±4.47%), however the membrane integrity of epididymal spermatozoa was higher than ejaculated spermatozoa (75.38±9.32% vs 65.54±11.88%) (P<0.05). In vitro fertilization experiment revealed that the ability of post-thawed epididymal spermatozoa to fertilize oocytes (61.40%, 42.98%, 18.42% for total, normal and polysperm, respectively) did not differ from that of ejaculated spermatozoa (66.67%, 48.78%, 17.89% for total, normal and polysperm, respectively) (P>0.05). These results indicate that ram spermatozoa collected from cauda epididymal and then frozen have the ability to fertilize ram ooctyes in vitro in the similar rate with ejaculated spermatozoa. The new cryopreservation protocol and reproductive technology describe here can enhance conservation of ram genetic resources.