INFLUENCE OF SOME CRYOPROTECTANTS IN COMPARING WITH DIFFERENT GLYCEROL LEVELS ON SPERM VIABILITY DURING FREEZING PROCESS OF GOAT SEMEN | ||||
Journal of Animal and Poultry Production | ||||
Article 6, Volume 33, Issue 7, July 2008, Page 4873-4885 PDF (581.03 K) | ||||
Document Type: Original Article | ||||
DOI: 10.21608/jappmu.2008.218056 | ||||
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Authors | ||||
A. E. Abdel-Khalek,1; M. M. El-Moghazy2; Sh. A. Gabr3 | ||||
1Anim. Prod. Dept., Fac. Agric., Mansoura Uni., Mansoura, Egypt. | ||||
2Anim. Prod. Dept., Fac. Agric., Minufiya Uni., Shebin El-Kom, Egypt. | ||||
3Anim. Prod. Dept., Fac. Agric., Tanta Univ. Egypt. | ||||
Abstract | ||||
A total of 160 good quality ejaculates were collected for freezing from 10 mature Zaraiby bucks (28.4±0.9 kg LBW and 25-35 mo old) in Sakha Research station during July-August period (twice/week for 8 wk) to determine the optimal level of, glycerol alone (1 to 7%, 1st experiment) and comparing the optimal level of glycerol with its combination with dimethyl sulfoxide (DMSO) and different levels (1, 3 and 5%) of ethylene glycol (EG), ethanol and methanol as cryoprotectants in Tris-based extender (2nd experiment), and the effect of the cryoprotectauts on sperm motility percentage (SMP) and recovery rate (RR%) at different freezing process stages (dilution, equilibrium and thawing). Results of the 1st experiment show that SMP in post-diluted and post-equilibrated semen was not affected significantly by glycerol (GL) level ranging between 79-81%. Loss in SMP between dilution and equilibrium ranged between 1-3% for all GL levels, being the lowest for 7% level and the highest for 5% level. Post-equilibrated RR of sperm motility ranged from 96.3 for 5% level to 98.8% for 4 and 7% levels. SMP showed gradual increase (P<0.05) from 20 to 48% by increasing GL level from 1 to 6%. Increasing GL level to 7% led to insignificant reduction in SMP (46%). Glycerol at 6% level showed the lowest (P<0.05) SMP loss (30%) and highest RR (61.5%) of sperm motility in post-thawed semen. The highest RR (72%) was obtained in 2 h post-thawed semen with 5% GL level, but did not differ significantly from that diluted with 6 and 7% levels. No viable spermatozoa were found 2 h post-thawing in semen diluted with extenders containing low glycerol levels (1 and 2%). Results of the 2nd experiment show that semen diluted with 6% GL showed the best results based on SMP and RR in post-diluted and post-equilibrated semen as compared to the other cryoprotectant levels. Level of 3% EG showed similar results to 6% GL level, while all methanol levels reflected the poorest results as compared to the other levels of cryoprotectants. In post-thawed semen, SMP and RR were the highest (P<0.05) and loss in SMP was the lowest (P<0.05) for 6% GL (47%), followed by 3% GL+3% DMSO and 6% DMS (39 and 34%, respectively). Non-viable spermatozoa were observed in 2 h post-thawed semen diluted with all levels of EG, ethanol or methanol. However, SMP in 2 h post-thawed semen was affected significantly (P<0.05) by diluents containing GL, DMSO or their combination, being 33, 16 and 24%, respectively. Similar trend was obtained for sperm recovery rate in 2 h post-thawed semen, being 70.0, 55.9 and 61.5%, respectively. The current study indicated that adding glycerol to Tris-based extender at level of 6% for cryopreservation of Zaraiby goat semen frozen in pellets form yielded the highest sperm motility in post-thawed semen. | ||||
Keywords | ||||
Zaraiby goat; semen; freezing; sperm motility; cryoprotectants; glycerol | ||||
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