The effect of thawing velocity on survival and acrosomal integrity of ram spermatozoa frozen at optimal and suboptimal rates in straws.
The effect of various thawing velocities on the motility and acrosomal maintenance of ram spermatozoa frozen at 20 degrees C/min (optimal) or 2 degrees C/min (suboptimal) was studied. The freeze-thaw motility and the percentage of intact acrosomes of spermatozoa frozen at 20 degrees C/min increased progressively with the thawing velocity. In semen frozen at 2 degrees C/min, motility of spermatozoa and the percentage of intact acrosomes declined drastically when the thawing velocity obtained in air at 20 degrees C was increased by thawing in water at 20 degrees C. Thawing at higher temperatures markedly increased both motility and acrosomal preservation, but the best results with semen frozen at 2 degrees C/min were lower than those obtained with semen frozen at 20 degrees C/min. The optimal freeze-thaw conditions for semen protected by 4% glycerol were freezing at 20 degrees C/min and thawing in water at 60 or 80 degrees C for 8 or 5 sec, respectively. Semen collected from rams exposed to a decreasing photoperiod exhibited higher motility after freezing and thawing than those exposed to an increasing photoperiod. However, there was no effect on acrosomal preservation after freezing at 20 degrees C/min.
Fiser
P S
PS
Fairfull
R W
RW
Marcus
G J
GJ
D000177:Acrosome / Q000648:ultrastructure*; D000818:Animals; D002470:Cell Survival; D005615:Freezing; D007700:Kinetics; D008297:Male; D008433:Mathematics; D012756:Sheep; D013094:Spermatozoa / Q000166:cytology / Q000648:ultrastructure*