Evaluation of DNA integrity of cryopreserved boer goat (Capra hircus) sperm using comet assay at various pH conditions.

A very wide range of temperature changes during cryopreservation process reported cause complications to the sperm. One of it is DNA damage on the sperm which has been identified during the freezing and thawing process. Comet assay is a useful tool in sperm DNA integrity evaluation. Alkaline and neutral comet assay were able to differentiate DNA single- and double-strand breaks. The objective of this study was to evaluate the DNA integrity of post-thaw Boer goat ( Capra hircus ) sperm using comet assay. The semen was collected using artificial vagina technique and cryopreserved in liquid nitrogen by slow-freezing cryopreservation protocol. DNA integrity of the sperm was evaluated using both neutral and alkaline comet assay immediately after thawing process. Tail moment and Olive tail moment were significantly higher under neutral condition (pH10) compared to alkaline condition (pH13) on post-thawed sperm (p<0.05). As a conclusion, cryopreservation of Boer goat sperm produces DNA double-strand breaks. The optimum detection of DNA strand breaks is at pH10.