title: Rat bioassays for methionine availability in 16 food sources.
abstract: Methionine availabilities of 16 test proteins were assessed by comparing ten day rat growth response to the test diets and reference (casein) diets. In a preliminary study, various concentrations of methionine and cystine were fed to determine methionine requirements and effect of excess cystine. Results indicated a methionine requirement of about 550 mg per 100 g diet. Cystine had a sparing affect of 50-55%, i.e., about 300 mg could be used to meet methionine requirements. Further additions of cystine (up to 2.6 times methionine) did not affect rat growth. Methionine availabilities were excellent (88-100%) for 15 of the 16 test foods; only pinto beans (58%) were low, but prior evidence indicates that the poor growth response was due to some factor other than availability.
authors.affiliation: U.S. Dept. of Agriculture, Beltsville Human Nutrition Research Center, MD 20705.
authors.forename: F E
authors.initials: FE
authors.lastname: McDonough
authors.forename: C E
authors.initials: CE
authors.lastname: Bodwell
authors.forename: R S
authors.initials: RS
authors.lastname: Staples
authors.forename: P A
authors.initials: PA
authors.lastname: Wells
mesh_terms: D000818:Animals; D002852:Chromatography, Ion Exchange; D003553:Cystine / Q000008:administration & dosage; D006358:Hot Temperature; D008715:Methionine / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism*; D009753:Nutritive Value; D051381:Rats; D015430:Weight Gain
chemical_list: D003553:Cystine; D008715:Methionine