Effects of trehalose and catalase on the viability and kinetic parameters of cryopreserved ram sperm

ABSTRACT

Background: Most part of ram spermatozoa membrane has unsaturated fatty acids (phospholipids). Membrane structure of cells is composed of double ordered phospholipid layers adorned with mosaic-like protein, glycoprotein and glycolipids. Sperm freezing protocols could be negatively affected on ram sperm motility, viability and acrosome integrity during cryopreservation. For these reasons, researchers were designed their topics has led to the search for effective antioxidant systems against peroxidative damage and spermatozoon dysfunction. There are three protective enzymatic systems against reactive oxygen species (ROS) damage in sperm. These include superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase / reductase cycles. Catalase is a hemo-protein in the enzyme tetramer structure. The aim of this study was to investigate the effects of trehalose, catalase and their combinations on ram sperm parameters after the cryopreservation/ thawing process.Materials, Methods & Results: At the out of breeding season (March-May) seven rams (1-3 years of age) were used in this study. Ejaculates were collected by electro-ejaculator twice a week. Pooled ejaculates were kept at 37°C, divided into six aliquots, diluted with the Tris based extender containing Trehalose 25 mM (Group-1), Trehalose 50 mM (Group-2), Catalase 200 µg (Group-3), Catalase 400 µg (Group-4), Trehalose 50 mM + Catalase 400 µg (Group-5) and no anti-oxidant (control), respectively, were cooled to 5°C than frozen in 0.25 mL French straws on the nitrogen vapour and stored in liquid nitrogen. The extender supplemented with Group 1 (54.1 ± 1.53; 73.1 ± 4.37), Group 2 (58.3 ± 4.01; 63.1 ± 0.30) and Group 5 (56.6 ± 1.05; 58.3 ± 0.55) resulted in higher subjective motility in comparison to the control (40.0 ± 3.87; 40.5 ± 0.22) group respectively (P < 0.05).[...]