Motility of gilthead seabream Sparus aurata spermatozoa and its relation to temperature, energy metabolism and oxidative stress

The present study characterized the motility parameters of Sparus aurata spermatozoa in relation to temperature, the main energy delivering pathways of motile spermatozoa, and the effect of antioxidants on sperm motility. The motility rate and swimming velocity decreased sharply during the first 1.5 min of the motility period. Thereafter, the motility rate and swimming velocity decreased moderately and a percentage of <20% of the spermatozoa remained motile for >2 h. The initial motility parameters 10 s after activation were not affected in a temperature range of 4-22 degrees C, while the motility parameters after 6 min were decreased at <10 degrees C. During motility S. aurata spermatozoa utilized fructose, triglycerides, and to a minor extent phospholipids as energy resources. Energy metabolism of S. aurata spermatozoa was stable during the motility period as ATP levels and phosphocreatine levels remained constant or even increased. S. aurata semen contained the antioxidants ascorbic acid, carnitine, glutathione, and uric acid and the oxidative defensive enzymes glutathione reductase, peroxidase, superoxide dismutase, and methionine sulfoxide reductase. Supplementation of the sperm activating saline solution with different types of antioxidants had no effect on the sperm motility. Also the concentrations of peroxides did not increase during motility. Therefore it is concluded that formation of reactive oxygen species and oxidative damage played no role during motility. (C) 2012 Elsevier B. V. All rights reserved.