Effect of soy lecithin on dog semen refrigeration and cryopreservation

Abstract

Semen cryopreservation is an essential step on the implementation of biotechnologies applied to reproduction. However, this technique is known to lead to a significant impairment on sperm quality. Despite several studies conducted aiming to improve post thaw semen quality, there is a general agreement that egg yolk provides the best results to avoid cryoinjuries for both cryopreservation and refrigeration. However, the great variation on egg yolk composition as well as the potential risk of disseminating diseases when used in natura, are obstacles to semen exportation and the use in human. Therefore, studies aiming to substitute the egg yolk for chemically defined components or animal free products are extremely important. In this context, soy lecithin, which contains a fraction of low density lipoproteins, appears to be an interesting alternative. Thus, the present study aims to compare semen extenders containing soy lecithin or egg yolk on dog semen cryopreservation and refrigeration. Towards this aim, semen of adult dogs will be refrigerated and cryopreserved in Tris-Fructose-Citric acid extenders with egg yolk (OVO) or soy lecithin (LEC; in different concentrations and presentations). Semen will be evaluated after chilling (0, 2, 6, 24 and 48 h) and after cryopreservation (pre cryopreservation and post thawing) for routine semen analysis (e.g., motility, CASA, morphological abnormalities) and functional tests (e.g., membrane integrity - eosin/nigrosin; acrosome integrity - fast green/Bengal rose; mitochondrial activity - 3'3 diaminobenzidine; DNA fragmentation - comet assay; susceptibility to oxidative stress - tiobarbituric acid reactive substances). Results will be statistically analyzed using the SAS System for Windows. (AU)