Special on the cat's metabolism is The lack to convert carotenoids to vitamin A; lack of ability to synthesise plenty of vitamin D; inability to synthesise niacin from tryptophan, lack of ability to synthesise cysteine, citrulline, and methionine; and an intolerance to glutamic acid.[15] Vitamin E being an antioxidant in https://www.petskyonline.com/shop-by-brand/