I. INTRODUCTIONCommercial poultry diets are routinely supplemented with methionine (Met) sources to precisely meet their Met+Cys specifications. Globally, dry DL-methionine (DL-Met, 99% purity) is the most commonly used Met source followed by methionine hydroxy analogue products (MHA-FA liquid, 88% purity and dry MHA-Ca, 84% purity) and L-methionine (LMet, 99% purity). During recent years, numerou ...