Vitamin E.

Vitamin E activity was first identified as a dietary factor essential for reproduction in the rat. It is now known that this vitamin has a far wider range of functions in the body than its role in fertility. It interacts with selenium-containing glutathione peroxidase to prevent the oxidative breakdown of tissue membranes associated with the hydroperoxides of polyunsaturated fatty acids. Relationships with other factors such as stress and vitamin C, have been proposed. The symptoms of deficiency of vitamin E vary according to species. With so many variables it is difficult to estimate the optimum allowances of the vitamin for the many types of livestock diets. These problems are discussed and the calculation of allowances of vitamin E in rations for both monogastric and ruminant animals is explained.