Cryopreservation of Dog Semen in a Tris Extender with 1% or 2% Soya Bean Lecithin as a Replacement of Egg Yolk

Abstract

Egg yolk is usually included in extenders used for preservation of dog semen. Lecithin is an interesting animal-protein free alternative to egg yolk for semen preservation. The aim of our study was to evaluate soya bean lecithin for cryopreservation of dog semen. Five ejaculate replicates were divided in three equal parts, centrifuged and each pellet diluted with one of the three Tris-based extenders containing 20% egg yolk, 1% soya bean lecithin or 2% soya bean lecithin. Extended semen was loaded in 0.5-ml straws, cooled and diluted a second time and frozen in liquid nitrogen vapours. Sperm motility parameters (CASA), acrosome integrity (FITC-PNA/PI) and sperm membrane integrity (C-FDA) were evaluated 5 min post-thaw and after 2 and 4 h of incubation. Total motility was significantly better in the egg yolk extender than in any of the lecithin-based extender and was better in the 1% lecithin extender than in the 2% lecithin extender. Sperm membrane integrity was significantly better in the egg yolk extender than in any of the lecithin-based extenders but did not differ significantly between the 1% and 2% lecithin extenders. Acrosome integrity was significantly better in the egg yolk extender than in the 2% lecithin extender but did not differ between the egg yolk extender and the 1% lecithin extender or between the two lecithin extenders. In conclusion, egg yolk was superior to lecithin in our study. The extender with 1% lecithin preserved sperm motility better than the extender with 2% lecithin.

Effects of egg yolk and soybean lecithin on sperm quality determined by computer‐assisted sperm analysis and confocal laser scanning microscope in chilled canine sperm

“…The obtained results clearly demonstrated that egg yolk is superior to soybean lecithin in Tris‐citric‐fructose or Tris‐citric‐fructose‐mineral salts extender when considering motility, plasma membrane integrity, acrosome membrane integrity and mitochondrial membrane potential parameters during 10 days of chilling storage. The results of the current study are in agreement with the previous reports in dogs (Axnér & Lagerson ), rams (Ustuner et al . ), and bulls (Crespilho et al .…”

“…Consequently, soybean lecithin is unsuitable for protecting sperm during storage. Thus, centrifuging and filtering are necessary to prepare soybean lecithin extenders as described earlier (de Paz et al 2010;Vick et al 2012;Axn er & Lagerson 2016). However, de Paz et al (2010 have also reported that the centrifugation-filtration process can reduce the quantity of phospholipids in extenders by 50%.…”

“…The composition of these extenders is shown in Table 1. Regarding the soybean lecithin extenders, the process of preparing the extenders was conducted with centrifuging and filtering as described by Axn er & Lagerson (2016).…”

Vitrification Using Soy Lecithin and Sucrose: A New Way to Store the Sperm for the Preservation of Canine Reproductive Function

“…A recent study in dogs showed that soy lecithin at low concentrations (0.01%, 0.05%, and 0.1%) was not able to maintain sperm characteristics when compared to egg-yolk-based extenders [28]. However, increasing the concentration of soy lecithin to 1% led to promising results on post-thaw semen viability and acrosome integrity in the current study, which is in agreement with previous studies [16,29,30]. This finding supports previous suggestions that high concentrations of soy lecithin are necessary to maintain canine sperm characteristics (i.e., motility kinetics) during storage [28].…”

Metformin Improves Quality of Post-Thaw Canine Semen

“…One of them is the oxidative stress leading to membrane perturbation and DNA damage. The aim of the extenders is to protect the semen against ice crystal formation, but also to improve the membrane and DNA quality in order to increase the success of fertilization [11,12]. The cryopreservative extender frequently used in veterinary practice could still be optimized to limit the plasma membrane degradation and DNA damage during chilled storage [13,14].…”