LOW STABILITY OF ASPARTATE-AMINOTRANSFERASE ACTIVITY IN BOAR SEMEN

This study was conducted to evaluate and characterize aspartate aminotransferase (AAT) activity in boar semen and to determine the effect of dilution on the activity. In the first experiment it was found that the activity of AAT which had leaked from spermatozoa increased gradually during semen storage in various diluents at 16-18-degrees-C. In, contrast, AAT activity was decreased after exposure of spermatozoa to cold-shock (1 hour, 4-degrees-C). Correlation between semen quality and the enzyme activity was greater after cold-shock than after storage at above-zero temperatures. Low stability of extracellular AAT pool was observed. In the second experiment, inactivation by dilution of AAT released after cold-shock was found. This phenomenon was prevented by the presence of 5% BSA. The AAT activity measured after cold-shock of spermatozoa by physiological saline with 5% BSA was 65% higher, than in samples without albumin. A high correlation between sperm concentration and amounts of the enzyme released in the presence of albumin was obtained (r=0.88).