Cryopreservation of rabbits spermatozoa: Effect of warming procedures, breed and post thawing incubation time [electronic resource].

Includes references.

The present work was conducted to determine the effects of three warming procedures (37OC/15s. 50OC/12s or 70DCIJ Os) and post-thawing incubation time (0 to 2 hrs) on in vitro assessment of sperm cryosurvival (motility) and acrosome status (.intact, modified and completely detached) of New Zealand White (NZW}and Baladi Black (BB) rabbits. Semen was collected from mature bucks (6 in each breed) three times a week (two ejaculates per male/time). Only ejaculates with >70% motility were considered, pooled and frozen in liquid nitrogen. Post-thaw sperm motility and intact acrosome percentages were significantly (P<0.001, 0.01 or 0.05) affected by different thawing procedures used, rabbit breeds, post-thaw incubation time and their interactions. There was a tendency to post¬-thawing motility and intact acrosome improvements when using moderate (50OC/12s) thawing procedure (27.44 and 39.44%) compared to rapid (70OC/10s. 21.50 and 33.67%) and slower (37"C1/5s, 17.33 and 28.33%) warming procedures. The highest percentage of post-thaw motility and intact acrosome (36.00 and 44.50%) were recorded when using moderate thawing procedure immediately after thawing, followed by 29.17 and 38.83% with the same warming procedure after one hour incubation. then 28.50 and 36.83% with thaw rate at 70OC/10s without incubation time. The higher percentage of structural abnormalities was observed with BB rabbits when using slow or rapid thawing procedures compared to NZW rabbits. It can be concluded that moderate warming procedure (50OC/12s) provided significantly more cryosurvival spermatozoa compared with the other thaw rates, especially in semen of the NZW rabbit bucks.

Summary in Arabic.

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