الفهرس | Only 14 pages are availabe for public view |
Abstract The present study was designed to investigate centrifugation protocols, type of diluent, dilution rate, type of cryoprotectant and cooling on post-thaw quality of Arabian stallion spermatozoa. Semen was collected from four adult pure Arab stallions on a regular basis (one ejaculate / week/ 10 successive weeks). After collection, semen was evaluated using conventional methods. Centrifugation protocols were done on gel free fraction (nocentrifugation, 600 xg/ 10,15 min.,900 xg / 10,15 min and 1200 xg / 10,15 min.). Two semen extenders were used: INRA-82 and modified Kenney’s extender at dilution rates of 1:1, 1:2 and 1:3. Glycerol 5%, dimethyl-formamide (DMF) 5% and glycerol 2.5%+ DMF 2.5% were used as cryoprotectants. Cooling over a period of 1 hr., 1.5 hr. and 2 hr was practice prior to freezing. The post-thaw studied parameters were progressive motility, live percentage, total abnormalities, viability index and plasma and acrosomal membrane integrities. Based on results of current study centrifugation of stallion semen at 600 xg for 15 minutes before cryopreservation could overcome the damaging effect of plasma membrane indicated by significant improvements of sperm characteristics of post-thaw spermatozoa. Dilution of centrifuged stallion semen with INRA-82 extender at a rate 1:1 could be used for improvement freezability of spermatozoa. Inclusion of DMF 5% in INRA-82 extender showed a significant improvement of sperm characteristics of post-thaw spermatozoa. Cooling of stallion semen to +50C over a period of 1.5 hr before freezing reduced damaging of spermatozoa, counteract cold shock and showed a significant improvement of sperm characteristics of post-thaw spermatozoa. Not only the protocol of freezing of stallion spermatozoa, but also individual variation in stallions crucial to achieve the desired goal for freezing of stallion spermatozoa. |