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Asian Journal of Andrology (2010) 12: 760-765. doi: 10.1038/aja.2010.48; published online 5 July 2010.
Supplemental effect of varying L-cysteine concentrations on the quality of cryopreserved boar semen
Kampon Kaeoket1, Panida Chanapiwat1,2, Padet Tummaruk2 and Mongko1 Techakumphu2
1 Semen Laboratory, Faculty of Veterinary Science, Mahidol University, Phuttamonthon, Nakorn-pathom 73170, Thailand
2 Department of Obstetrics Gynaecology and Reproduction, Faculty of Veterinary Science, Bangkok 10330, Thailand
Correspondence: Dr Kampon Kaeoket, Semen Laboratory, Faculty of Veterinary Science, Mahidol University, Nakorn-pathom 73170, Thailand. Fax: +662-4410-937 E-mail: vskkk@mahidol.ac.th
Received 4 January 2010; Revised 23 April 2010; Accepted 28 April 2010; Published online 5 July 2010.
| Abstract |
Cryopreservation is associated with the production of reactive oxygen species, which leads to lipid peroxidation of the sperm membrane and consequently a reduction in sperm motility and decreased fertility potential. The aim of this study was to determine the optimal concentration of L-cysteine needed for cryopreservation of boar semen. Twelve boars provided semen of proven motility and morphology for this study. The semen was divided into four portions in which the lactose-egg yolk (LEY) extender used to resuspend the centrifuged sperm pellet was supplemented with various concentrations of L-cysteine to reach 0 mmol L−1 (group I, control), 5 mmol L−1 (group II), 10 mmol L−1 (group III) and 15 mmol L−1 (group IV). Semen suspensions were loaded in straws (0.5 mL) and placed in a controlled-rate freezer. After cryopreservation, frozen semen samples were thawed and investigated for progressive motility, viability using SYBR-14/EthD-1 staining and acrosome integrity using FITC-PNA/EthD-1 staining. There was a significantly higher (P < 0.01) percentage of progressive motility, viability and acrosomal integrity in two L-cysteine-supplemented groups (group II and group III) compared with the control. There was a biphasic effect of L-cysteine, with the highest percentage of progressive motility, viability and acrosomal integrity in group III. In conclusion, 5 or 10 mmol L−1 was the optimum concentration of L-cysteine to be added to the LEY extender for improving the quality of frozen–thawed boar semen.
Keywords: antioxidant; boar semen; cryopreservation; L-cysteine |
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