Effects of Soy Lecithin Extender on Dog Sperm Cryopreservation

Abstract

Semen cryopreservation is an essential biotechnology in canine reproduction and during the cryopreservation process commonly egg yolk are used. The discrepancy in the egg yolk composition and the potential risk of disease dissemination are obstacles for semen exportation and use. Therefore, studies aiming to substitute egg yolk are extremely important. In this context, soy lecithin contains a low-density lipoprotein fraction, is an interesting alternative. Thus, the objective of this study was to compare extenders based on soy lecithin (several concentrations and forms) with egg yolk during the cryopreservation process of dog sperm. For this purpose, we used twelve dogs. Semen was evaluated at different time points (after refrigeration, glycerolization, and thawing), by motility analysis (CASA) and functional tests (e.g., membrane integrity-eosin/nigrosin, acrosome integrity-fast green/Bengal rose, mitochondrial activity-3'3 diaminobenzidine, Chromatin susceptibility to acid-induced denaturation-SCSA, and susceptibility to oxidative stress-thiobarbituric acid reactive substances). The results indicated that egg yolk and lower concentrations of lecithin had similar effects on mitochondrial activity and motility. Thus, soy lecithin is a potentially viable alternative to egg yolk for the cryopreservation of dog semen.

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

“…In another study on chilled canine sperm, motility, plasma membrane integrity and mitochondrial membrane potential in soybean lecithin (0.4%) extender were found to be greater than those in 20% egg yolk extender during 10 days of storage (Kasimanickam et al 2012). Furthermore, several investigations have proven that soybean lecithin could replace egg yolk in extender to protect sperm during cryopreservation in dogs (Beccaglia et al 2009a,b;Dalmazzo et al 2018), goats (Salmani et al 2014;Chelucci et al 2015;Yotov 2015), bulls (Aires et al 2003;El-sisy et al 2016), rams (Masoudi et al 2016), stallions (Nouri et al 2013), rabbits (Nishijima et al 2015) and fish (Yildiz et al 2013). The difference between our results and previous studies may be due to the difference in soybean lecithin sources, the preparation for soybean lecithin extenders and the concentrations of soybean lecithin.…”

“…Moreover, Dalmazzo et al . () have explained that high concentrations of soybean lecithin (phosphatidylcholine) can cause higher concentrations of exogenous phosphatidylcholine inside the mitochondria and lead to an imbalance between intracellular and extracellular as the result of reducing mitochondrial activity as well as motility.…”

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

“…Egg yolk, BSA, and lecithin are proteins known for their protective qualities against the initial cold shock during the freezing process. Soy lecithin can also serve as an antioxidant and can protect semen from oxidative stress resulting in higher viability and motility after cryopreservation [16]. 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].…”

“…According to the Dalmazzo et al [16], who was comparing different forms of soy lecithin on frozen canine semen samples, Solec F (Solae F, Solae Company, St. Louis, MO, USA) exhibited best results and was therefore used in our study. In our preliminary study, the best concentration of soy lecithin to be added to the vitrification media was determined and the following concentrations: 1%, 2%, 3% and 4% (wt/vol) were compared on five canine semen samples.…”

“…In a recent study on canine semen, soy lecithin was found to be a viable alternative to egg yolk with a similar effect on mitochondrial activity and motility of cryopreserved dog semen. Moreover, samples frozen in soy-lecithin-based extenders resulted in lower lipid peroxidation compared to egg yolk extenders, which is important since oxidative stress is one of the major problems in stored semen [16].…”