EFFECT OF FASTING ON BLOOD LIPID-PEROXIDATION PARAMETERS OF SHEEP

The effects of three-day fasting and one-day refeeding on some blood m etabolites and parameters of lipid peroxidation were studied in eight non-pregnant merino ewes. Fasting produced an immediate decrease in bl ood glucose accompanied by an increase of free fatty acid, total lipid , total cholesterol and urea in the plasma. Starvation increased the c oncentration of thiobarbituric acid-reactive substances (malondialdehy de), with a slower but more sustained increase in the plasma than in t he red blood cell haemolysate. Changes in glutathione peroxidase activ ity were the reverse of those in malondialdehyde concentration. Catala se activity was not measurable in plasma but was consistently increase d in the haemolysate on fasting. Superoxide dismutase activity in the whole blood haemolysate significantly increased only on the first day of food deprivation. The vitamin E content of plasma showed no signifi cant changes. The results indicate that energy deficiency, a well-know n phenomenon in ruminants, affects not only the metabolic parameters o f the blood but its lipid peroxidative status as well.