Vitamin U (DL-methionine methylsulfonium chloride) is a natural methionine-derivative, found as an active component in the methionine cycle of plants where it serves as a substrate for methyl transferases (Augspurger et al., 2005). Historically this compound has been utilized as either a cure or preventative against gastric and duodenal ulcers (Nakamura et al., 1981). Vitamin U has been shown to aid in an overall increased weight gain of 3.6% and to decrease feed efficiency by 2.0% when included in a hog-fattening ration at 25 mglkg of feed (Solntsev and Filipovich, 1981).
