Upid Peroxidation in Semen of the Boar

Smutna M., o. Synek: Lipid Peroxidation in Semen of the Boar. Acta vet. Bmo, 48, 1979: 35-43. During the catalyzed aerobic incubation of the complete boar semen malonyldialdehyde (MDA) is produced. MDA is a good indicator of peroxidative decomposition of polyunsaturated fatty acids. Detection of peroxidation products was conducted both by colour reaction with 2-thiobarbituric acid (evidence of MDA), and spectrofotometrically (evidence of the conjugated dienes, oxidation of the coenzyme NADPH + H+). It was found that the progressive formation of MDA surpasses the formation of conjugated dienes especially in the early stages of peroxidation. Significant correlation for the first 30 minutes of the aerobic incubation was found between the number of spermatozoa and the amount of produced malonyldialdehyde. Enzymatic lipid peroxidation studied in isolated tails of spermatozoa was NADPH-dependent with a small dependence on pyrophosphate. Production of MDA in all studied systems was infiuenced by pH of the environment. The boar seminal plasma showed high anti-peroxidative activity limited by its dilution. Native semen, malonyldialdehyde, conjugated dienes, inhibitory effect. Properties ofthe membranes determine largely the properties of the cells and tissues. Viability of each animal cell depends on structural and functional integrity of its membrane and subcellular structures. The quality of the membrane is also important for viability of spermatozoa and for metabolic processes ensuring their contact to the environment. Changes in the properties of these membranes result in functional and morphological aberations the character of which is given by the degree of damage to the membrane. The labile compound of the membranes are unsaturated fatty acids esterified in phospholipids which together with globular proteins represent the basic structural components of all biological membrane complexes. Non-enzymatic peroxidative breakdown of unsaturated fatty acids of the membrane to small fragments impairs their function in _the lipoprotein membrane and injurs seriously their structural and functional integrity. Destruction of specific membrane phospholipids during the NADPH-induced lipid peroxidation of the microsomal fraction from rat liver was demonstrated by May and Mc Cay (1968). Decomposition by peroxidation of the chain of polyunsaturated fatty acids esterified in the beta position of phosphatidylcholine and phosphatidylethanolamine of the microsomal membrane resulted in a 40 % decrease in the amount of arachidonic acid. The harmful effect of HaO. and dialuric acid on the erythrocyte membranes in rats suffering from E hypovitaminosis lead to partial damage to phosphatidylethanolamine, phosphatidylcholine and phosphatidylserine (Heikkila et al. 1971). Changes in the concentration of phospholipids in the boar semen were found to be caused by its aerobic incubation with Cu++ ions (Smutna 1974). Loss of plasmalogen and palmitaldehyde from the ram sperm and loss of motility of spermatozoa with their spontaneous agglutination was found by Jones and Mann (1976). Damage to ram spermatozoa due to peroxidation of endogenous phospholipids was observed by the same authors (J ones and Mann 1977). Impaired functional integrity manifesting itself by changed permeability to K + and Na+ in irradiated erythrocytes was demonstrated by Gerber and Altman (1970), glucose eftlux through an artificially prepared membrane (Hicks and Gebicki 1977) and impaired permeability of E. coli membrane for the K+ ions were observed (Suzuki and Akamatsu 1978).