FeedManufacturing.com: Animal Feed, Feed Ingredients & Feedstuffs
A vitamin is an organic compound required in tiny amounts for essential metabolic reactions in a living organism. The term vitamin does not include other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids, nor does it encompass the large number of other nutrients that promote health but that are not essential for life.
Vitamins are classifiable as water soluble viatmins and fat-soluble vitamins.