AAFCO Ch6 dl methionine

AAFCO Ch6 definition 6.2 DL-Methionine is a product containing a minimum of 99% racemic 2-amino-4-(methylthio)butanoic acid; the percentage of DL-Methionine must be guaranteed (Adopted 1957, Amended 1975, 1978, 1989, 2005, 2009, Adopted 2011; 21 CFR 582.5475; IFN 5-03-086). Methionine is an essential amino acid for both dogs and cats; per the AAFCO 2014 cat food nutrient profile (DM basis), the methionine minimum is 0.62% for Growth & Reproduction and 0.20% for Adult Maintenance (methionine-cystine 1.10% / 0.40% respectively), while the dog profile sets methionine at 0.35% (G&R) / 0.33% (Adult) DM. DL-Methionine is the synthetically produced racemic form used to supplement plant-protein-based formulas (corn gluten, soy) that are relatively low in methionine. Heavy supplementation acidifies urine, a property deliberately used in some urinary-health formulations.