EFFECT OF DIETARY SELENIUM DEPLETION AND REPLETION ON PLASMA GLUTATHIONE PEROXIDASE ACTIVITY AND SELENIUM CONCENTRATION IN BLOOD AND BODY TISSUE OF GROWING PIGS

Abstract

The biodynamic relationship between blood Se concentration and the activity of the enzyme glutathione peroxidase (GSH-Px) in the plasma of piglets weaned at 2 wk of age was studied during a period of dietary Se depletion and repletion in the presence of adequate amounts of vitamin E. Blood SE concentration behaved as a sensitive index of the dietary SE intake. GSH-Px enzyme activity in the plasma, as a direct measurement of functional Se in one body compartment, was also very sensitive to dietary Se intake of the animals. Although dramatic changes in these two blood constituents were observed in the experimental animals during Se depletion and repletion, at the end of the experiment when they were killed for tissue sampling, no gross abnormalities were observed in any of the body organs of these animals. Body tissues showed a differential response to dietary Se manipulation; however, all of them were significantly affected in the 5-wk period. Overall, the liver appears to be the organ with the fastest rate of repletion or depletion of Se. The brain, at the other end of the spectrum of the tissues studied, appeared as the organ least affected by either Se depletion or repletion. Since the major interest is in the differential diagnosis of dietary Se deficiency in the live animal, plasma GSH-Px activity proved to be a fast, simple, and reliable method to evaluate the short-term intake of dietary Se.