Factors affecting serum creatine phosphokinase activity in pigs.

Serum creatine phosphokinase activity was determined in German Landrace and Landrace x Large White pigs from 11 weeks to 28 weeks of age. A very pronounced age dependence of enzyme activity was observed in both groups, peak activities occurring at 19 weeks of age for the German Landrace and at 15 weeks for the crosses. The large increase in serum creatine phosphokinase activity observed occurred during the rapid phase of growth after which enzyme levels returned close to initial values. Sedatives and the stress of handling while obtaining blood can also cause raised serum creatine phosphokinase levels and complicate the interpretation of the data in regard to the detection of the stress syndrome. Enzyme activity also displayed a diurnal variation thus introducing a further parameter in the use of creatine phosphokinase activity for detection of the stress syndrome. Certain limitations in the method of measurement of creatine phosphokinase are discussed.