Vitamin E in immunity and reproductive performance in pigs.

This review is focused on studies of vitamin E in immunity and reproductive performance in pigs. There are reports that vitamin E can have a positive effect on some parameters of the immune system in pigs. The optimal level of vitamin E needed to improve the immune system has not been determined because of several factors such as the composition of the diet, feed consumption, the rate of animal growth and living conditions or stress. Moreover, the way of action of vitamin E in enhancing immunity is still unclear but according to reports it may have antioxidant properties as well as an immunomodulator effect. In several studies, an increase in litter size and a reduction of preweaning piglet mortality have resulted from increasing dietary vitamin E intake during gestation or by intramuscular injection of vitamin E and/or selenium. However, according to reports, the positive effect of vitamin E on reproductive performance remains unclear due to the low number of animals used in most experiments.