Cryopreservation of rabbits spermatozoa: effects of cryprotectant agents, clarified egg yolk and post-thawing incubation time [electronic resource].

Includes references.

The present work was conducted to determine the effects of two cryprotectant agents (DMSO and DMSO-Glycerol) with or without clarified egg yolk (CEY) and post-thawing incubation time on the cryosurvival of New Zealand White rabbits spermatozoa. Semen was collected from 6 mature bucks (at 10-12 months of age with an average body weight of 3.92±0.24 kg) three times a week (two ejaculates per male/time). Only ejaculates with >70% motility were considered, pooled and frozen in liquid nitrogen. Post-thawing, sperm cryosurvival was judged in vitro by microscopic light and scanning electron assessments for motility and acrosome status (intact, modified and completely detached). The percentage of post-thawing motility and acrosome status of rabbit spermatozoa were significantly (P<0.001 or 0.05) affected by cryprotectant agents, inclusion CEY and post-thawing incubation time. Extended spermatozoa in DMSO-Glycerol-CEY significantly (P<0.001) increased the percentages of post-thaw motility and intact acrosomal, followed by those extended with DMSO-CEY and DMSO-Glycerol. The lowest percentages of post-thaw motility and intact acrosomal were recorded in spermatozoa extended with DMSO without CEY. Thawing spermatozoa and incubated for 2 hrs at 37°C, reduced (P<0.001) sperm motility (longevity) from 24.85 to 12.7% extended with CEY, whereas, from 22.25 to 6.85% when extended without CEY. There was a loss in sperm motility extended with DMSO from 21.45 to 9.53%, and from 25.6 to 10.05% with DMSO-Glycerol when thawed spermatozoa and incubated for 2 h at 37°C. Structures of frozen-thawing spermatozoa test revealed increased structural abnormalities, changes observed with the damaged membrane in the acrosome, bent midpiece and thickening of the midpiece, coiled tail, and detached tail. Frozen-thawing spermatozoa extended in DMSO-Glycerol-CEY showed the lowest damage in acrosome and tail, followed by those extended in DMSO-CEY than other extenders. It can be concluded that cryopreserved of rabbit spermatozoa in extender combined between DMSO-Glycerol-CEY significantly alleviate the harmful effects during cooling and freezing processes.

Summary in Arabic.

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