Preliminary Results: The Advantages of Low-Density Lipoproteins for the Cryopreservation of Equine Semen

Cryopreservation of rabbit semen using non-permeable cryoprotectants: Effectiveness of different concentrations of low-density lipoproteins (LDL) from egg yolk versus egg yolk or sucrose

“…This determines that outcomes can be improved by adding extracted LDL to the extender rather than whole egg yolk. Our results are consistent with those obtained in bull (Moussa et al, 2002;Vera Munoz et al, 2009;Amirat-Briand et al, 2004Hu et al, 2010Hu et al, , 2011, boar (Hu et al, 2006(Hu et al, , 2008Jiang et al, 2007), dog (Bencharif et al, 2008, buffalo (Akhter et al, 2011), ram (Moustacas et al, 2011) and horse (Moreno et al, 2013). Low-density lipoproteins (0.982 g/mL) appear in the soluble fraction of egg yolk called plasma.…”

“…In effect, egg yolk has been widely used in semen freezing extenders and proven to offer resistance against cold shock during the sperm freeze-thaw process in several animal species (Holt, 2000;Moussa et al, 2002;Mocé and Vicente, 2009). However, the use of egg yolk as a CPA has several drawbacks besides being a source of bacterial contamination (Moreno et al, 2013) and some of its constituents could have detrimental effects on spermatozoa. Accordingly, the granules found in egg yolk were observed to reduce the respiration and motility of bull spermatozoa (Amirat-Briand et al, 2004), and progesterone in egg yolk has been described as potentially responsible for the capacitation of spermatozoa and thus harmful for the preservation of spermatozoa during freezing (Bowden et al, 2001;Moreno et al, 2013).…”

“…However, its protective action is largely thought to be due to low-density lipoproteins (LDL), as the main constituents of egg yolk (2/3 of dry yolk matter). Many investigations have confirmed these findings in bull (Hu et al, 2011), boar (Hu et al, 2006), dog (Bencharif et al, 2008), buffalo (Akhter et al, 2011), ram (Moustacas et al, 2011) and horse (Moreno et al, 2013). However, to the best of our knowledge the use of LDL as a non-permeable CPA has not yet been tested in the rabbit.…”

Membrane stability and mitochondrial activity of bovine sperm frozen with low‐density lipoproteins and trehalose

“…Centrifuged chicken egg yolk is known for reducing the harmful components of egg yolk through centrifugation (Nouri et al, 2013). In this regard, it has been reported that egg yolk contains HDL that decrease the metabolism of bull sperm (Moreno et al, 2013). Likewise, CCEY could retain some antioxidants, which have been associated with beneficial effects on cryopreservation of bovine semen (Güngör, Ata, İnanç, & Kastelic, 2019).…”

“…Since the inception of bovine semen cryopreservation, egg yolk and milk-based extenders have been used to protect sperm from the detrimental effects of cooling and freezing (Layek, Mohanty, Kumaresan, & Parks, 2016). However, egg yolk contains substances that inhibit the metabolism of spermatozoa, reducing their motility, acrosomal integrity and ability to fertilize the ovum (Moreno et al, 2013). Alternatively, it has been shown that centrifuged chicken egg yolk (CCEY) or purified low-density lipoproteins (LDL) from egg yolk can improve the quality of post-thaw semen (Moussa, Martinet, Trimeche, Tainturier, & Anton, 2002;Nouri, Towwhidi, Zhandi, & Sadeghi, 2013;Vera-Munoz et al, 2011).…”