AKAL, Eser Ondokuz Mayıs Üniversitesi - Veteriner Fakültesi - Dölerme ve Suni Tohumlama AD, Turkey , KOÇYİĞİT, Alper Ondokuz Mayıs Üniversitesi - Veteriner Fakültesi - Dölerme ve Suni Tohumlama AD, ‎Turkey , SELÇUK, Murat Ondokuz Mayıs Üniversitesi - Veteriner Fakültesi - Dölerme ve Suni Tohumlama AD, Turkey

Role of Low Density Lipoproteins in Semen Preservation

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The discovery that egg yolk has a beneficial effect on fertility in semen extenders led to its widespread use in semen extenders. Egg yolk is commonly found in semen extenders to preserve mammalian spermatozoa against cold shock during freeze-thaw process. Protective action of yolk is largely presumed to be due to low density lipoproteins (LDL). In recent years, there have been increasing demands to replace whole yolk in semen extenders because of presence of substances in yolk that inhibit respiration of spermatozoa or diminish their motility. Consequently, it could be of great benefit to remove these detrimental substances in yolk rather than complete egg yolk. Recent studies have confirmed that LDL extracted from egg yolk is successful for cryopreservation of semen from various species. Density gradient ultracentrifugation has been generally used for purification of egg yolk LDL. LDL are composed of 84-89% lipids and 11-17% proteins. Lipids of LDL are composed of approximately 69% triglycerides, 26% phospholipids and 5% cholesterol. Phospholipids play an essential role in the stability of LDL structure because association forces are essentially hydrophobic. LDL presents a density of 0.982 g/ml. They are spherical molecules of 17- 60 nm diameters. The interactions of lipid and protein are disrupted and under freezing, but interactions between proteins are increased and adhere to cell membranes, thus preserving spermatozoa membranes. In conclusion, researches are still carried out needed to evaluate and understand the respective roles of lipids and apoproteins from LDL and to isolate the antagonistic agent contained in egg yolk.

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Cryopreservation , Egg Yolk , LDL , Semen

Kocatepe Veterinary Journal

74