Veterinary Pharmacology and Therapeutics (6th Edition) states the following:
Selenium is now known to be essential for tissue respiration and is protective against dietary hepatic necrosis. It is extremely active and is only required in minute amounts. Vitamin E enhances the action of Selenium, but both are required.
Selenium is an essential component of glutathione peroxidase, which catalyzes oxidation of reduced glutathione.
The glutathione peroxidase catalyzes removal of hydrogen peroxide and fatty acid hydroperoxides and so exerts a protective effect on all cells, but especially on muscle, liver and erythrocytes. The essential substances required for removal of peroxides are reduced glutathione and glutathione peroxidase. Vitamin E maintains glutathione in the reduced form by preventing formation of hydroperoxides; it is an antioxidant and so reduces the amount of glutathione peroxidase required. Cysteine (N-acetylcysteine) is required for the reduced sulfhydryl radical of glutathione and is generally present in adequate quantities. Selenium and vitamin E enhance each other’s reaction and together protect cells, especially hepatocytes, against harmful buildup of peroxides.
PRECAUTION: DO NOT EXCEED THE RECOMMENDED DOSAGES
Not to be fed in conjunction with other supplements containing Vitamin E or Selenium, if in doubt consult registration holder.
Adult Horse: Give 10 ml orally twice weekly. Best given prior to hard work and competition days.
Pour the required dose in 2 – 3 places on top of the feed, mix in lightly. Alternatively the measured dose of Liquid SeeVitE may be drawn into a liquid syringe and deposited on the back of the tongue.
Iron is an antagonist of Vitamin E. Therefore we recommend that when giving Liquid SeeVitE concurrently with any supplement containing iron, that Liquid SeeVitE be given in the morning feed and the iron supplement in the evening feed. Alternatively Liquid SeeVitE can be administered by an oral syringe, preferably 30 minutes prior to feeding the iron supplement.