Effect of Plasma Vitamin E Levels on Tween 20 Hemolysis of Goat Erythrocytes

To investigate the relationship between blood plasma alpha-tocopherol levels and the hemolysis induced by Tween 20, blood plasma of varying alpha-tocopherol contents were obtained by oral (100mg/day) or intramuscular (3mg/kg body weight) administration of alpha-tocopheryl acetate in goats fed either Italyan ryegrass silage or maize silage with concentrate. The alphatocopherol levels were determined by high-performance liquid chromatography. Alpha-tocopherol contents of blood plasma varied from 0.88 to 6.91μg/ml.Mean plasma alpha-tocopherol contents of the goats fed Italyan ryegrass silage and maize silage were 1.25 and 3.77μg/ml, respectively. The alpha-tocopherol levels became significantly higher lweek after oral administration of vitamin E. A large amount of alpha-tocopheryl acetate remained in the blood plasma for more than 24 hours after intramuscular administration. The peak levels of free-form and total alphatocopherol were 5.53 and 19.03μg/ml, respectively. The red blood cells were tested for the susceptibility to the Tween 20-induced hemolysis with 2.5, 1.25 and 0.5% Tween 20 concentration each week. 2.5 and 1.25% Tween 20-induced hemolysis and the plasma alpha-tocopherol levels showed reciprocal relationships. When plasma alpha-tocopherol levels decreased to 2.0μg/ml or less, goat red blood cells showed progressively-increased hemolysis of more than 20%.