The advantages of low-density lipoproteins in the cryopreservation of bull semen

• Published in: Cryobiology 2011-02, Vol.62 (1), p.83-87
• Main Authors: Hu, Jian-Hong, Jiang, Zhong-Liang, Lv, Rui-Kai, Li, Qing-Wang, Zhang, Shu-Shan, Zan, Lin-Sen, Li, Yao-Kun, Li, Xin
• Format: Article
• Language: English
• Subjects: Acrosome - drug effects; Animal productions; Animals; Anti-oxidant activities; Antioxidants; Biological and medical sciences; Bull semen; Catalase - drug effects; Cattle; Cell Membrane - drug effects; Cryopreservation; Cryopreservation - methods; Cryopreservation - veterinary; Cryoprotective Agents - pharmacology; Diverse techniques; Egg Yolk - toxicity; Fundamental and applied biological sciences. Psychology; Glutathione - drug effects; Glutathione Peroxidase - drug effects; Lipoproteins, LDL - pharmacology; Low-density lipoproteins; Male; Molecular and cellular biology; Semen - drug effects; Semen - metabolism; Semen Preservation - methods; Semen Preservation - veterinary; Semen quality parameters; Sperm Motility - drug effects; Spermatozoa - metabolism; Terrestrial animal productions; Vertebrates
• ISSN: 0011-2240; 1090-2392
• DOI: 10.1016/j.cryobiol.2010.12.007

Egg low-density lipoprotein (LDL) was added at concentrations (w/v) of 7%, 8% or 9% to the extenders used to freeze bull semen and its effects on seminal parameters and anti-oxidant activities of frozen–thawed sperm were assessed. Analysis of data showed that sperm exposed to 8% LDL exhibited the greatest percentages of sperm motility, acrosome integrity and membrane integrity, compared to the control which differed from the treatment groups by replacing LDL with 20% egg yolk ( P < 0.05). No difference was observed for membrane integrity between 8% and 9% LDL groups ( P > 0.05). The extender supplemented with LDL did not exhibit improvement in SOD levels. However, 8% LDL group favored the highest anti-oxidant activities of CAT, GSH-Px and GSH in comparison to other groups (7%, 9% LDL and the control) ( P < 0.05). No difference was observed for CAT activity between 9% LDL and the control group. In conclusion, sperm cryopreserved in the extender containing 8% LDL in place of egg yolk exhibited the greatest percentages of post-thaw sperm motility, acrosome integrity and membrane integrity, in comparison with the control, and favored the highest anti-oxidant activities of CAT, GSH-Px and GSH in comparison with other groups. The replacement of egg yolk by LDL in the composition of extenders was beneficial for bull sperm cryopreservation.