The cryoprotective effect of low-density lipoproteins in extenders on bull spermatozoa following freezing-thawing.
Egg low-density lipoprotein (LDL) was added at concentrations of 7-10% to the extenders used to freeze bull semen and its effects on the motility, mitochondria activity, acrosome integrity, membrane integrity and DNA integrity of frozen-thawed sperm were assessed. Analysis of data showed that the motility and characteristics of spermatozoa movement were higher with LDL in the extender, as compared to the extender containing 20% egg yolk. The results indicated that 8% LDL supplementation provided the highest sperm motility (55.8%) and movement characteristics (VSL, straight linear velocity: 33.8 microm/s; VCL, curvilinear velocity: 50.2 microm/s; LIN, linearity index: 56.5%; STR, mean coefficient: 76.7%; VAP, average path velocity: 35.9 microm/s; WOB, wobble coefficient: 63.9%). A concentration of 10% LDL resulted in a significant decline in the VSL, LIN, VAP and WOB values (P<0.05). Supplementation of LDL at 8% LDL resulted in significantly higher spermatozoa mitochondrial activity, acrosome integrity, membrane integrity and DNA integrity (P<0.05). According to all measured parameters, the extender containing 8% LDL showed beneficial cryoprotective effects on frozen-thawed bull spermatozoa. In conclusion, our results indicated that the extender containing 8% LDL extracted from egg yolk could be used successfully in the cryopreservation of bull semen with an efficacy that would be greater than present extenders containing 20% egg yolk.
Hu
Jian-Hong
JH
College of Animal Science and Technology, Northwest A & F University, Yangling, Shaanxi Province 712100, PR China.
Li
Qing-Wang
QW
Zan
Lin-Sen
LS
Jiang
Zhong-Liang
ZL
An
Jun-Hui
JH
Wang
Li-Qiang
LQ
Jia
Yong-Hong
YH
D000177:Acrosome / Q000648:ultrastructure; D000818:Animals; D002417:Cattle; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000008:administration & dosage*; D004247:DNA / Q000737:chemistry; D006358:Hot Temperature; D008077:Lipoproteins, LDL / Q000008:administration & dosage*; D008297:Male; D008928:Mitochondria / Q000502:physiology; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013081:Sperm Motility; D013094:Spermatozoa / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure
D003451:Cryoprotective Agents; D008077:Lipoproteins, LDL; D004247:DNA