title: D-allothreonine has no growth promoting efficacy for chicks.
abstract: One hundred and sixteen crossbred male chicks were used in two battery trials to establish the biological efficacy and toxicity of D-allothreonine (D-allo-Thr) relative to L-Thr. In the efficacy trial, graded doses of D-allo-Thr or L-Thr were added to a Thr-deficient (0.24% L-Thr) chemically defined diet and fed to chicks during the period 10 to 21 d posthatching. Addition of 0, 0.09, and 0.18% L-Thr produced marked linear (P < 0.01) growth and feed efficiency responses, but addition of 0.18 or 0.36% D-allo-Thr did not elicit a response in either weight gain or feed efficiency. In the toxicity trial, 2% D-allo-Thr or 2% L-Thr were added to a conventional 23% CP corn-soybean meal starter diet. During an 11-d feeding period, neither weight gain nor voluntary feed intake were affected (P > 0.10) by 2% additions of either compound. This experiment demonstrates that chicks cannot metabolize D-allo-Thr to L-Thr and that neither L-Thr nor D-allo-Thr are growth depressing when provided in a large surfeit.
authors.affiliation: Department of Animal Science, University of Illinois, Urbana 61801, USA. d-baker1@uiuc.edu
authors.forename: D H
authors.initials: DH
authors.lastname: Baker
authors.forename: D M
authors.initials: DM
authors.lastname: Webel
authors.forename: S R
authors.initials: SR
authors.lastname: Fernandez
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000254:growth & development*; D004032:Diet; D004435:Eating; D005260:Female; D007536:Isomerism; D008297:Male; D013912:Threonine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology*; D015430:Weight Gain / Q000187:drug effects
chemical_list: D013912:Threonine