Effects of Vitamin E-Enriched Egg Yolk on Lipid Peroxidation, Hemolysis and Serum Lipid Concentration in Young and Old Rats.

Abstract

Effects of a diet containing different amount of vitamin E-enriched egg yolk powder on lipid peroxidation, hemolysis, and serum lipid concentration were examined in young and old rats. Young and old rats were fed experimental diets containing 5.6% or 22.5% of normal egg yolk powder, and 5.6% or 22.5% of vitamin E-enriched egg yolk powder. When young rats were fed these diets, their tocopherol concentrations in testes, heart, kidneys, and retroperitoneum fat pads increased according to the diet tocopherol contents. Lipid peroxide levels in these tissues were inversely proportional to the tocopherol concentrations. The liver and serum, however, did not show the above relationship. In the rats fed vitamin E-enriched egg yolk diets hemolysis did not increase, in contrast to those fed normal egg yolk diets. The rats fed a 5.6% vitamin E-enriched egg yolk diet had a lower serum cholesterol level than those fed a normal egg yolk diet. In old rats, one control group was used to determine initial tocopherol concentration and two other groups were fed 5.6% normal and vitamin E-enriched egg yolk diets. The vitamin E-enriched egg yolk rats showed lower weights of the body, liver, and retroperitoneum fat pads at the end of the experiment. The normal egg yolk group had atrophied testes. The tissue and serum tocopherol concentrations were increased in the vitamin E-enriched egg yolk group, whereas they were decreased in the normal egg yolk group. In the vitamin E-enriched egg yolk group, lipid peroxide, hemolysis and serum cholesterol, especially HDL-cholesterol, did not increase. These results indicate that egg yolk tocopherol was absorbed and prevented lipid peroxidation and hemolysis in young and old rats, and testes atrophy in old rats.