title: Dietary tryptophan effects on growth and stress responses of male broiler chicks.
abstract: 1. Three experiments were conducted to determine growth of broiler chicks fed on test diets formulated to be deficient or adequate in tryptophan (Trp) using gelatin by-product as a means of generating a Trp deficiency. Growth response estimates of broiler chicks to graduations of Trp were determined by dose-response criteria and regression analyses. Experiments were conducted using broiler chicks from 1 to 20 d of age. 2. Broiler chicks fed Trp-deficient diets had poor body weight gain, feed intake and feed conversion. Recommended total Trp needs were 2.0, 2.1 and 2.2 g/kg for feed intake, body weight gain and feed conversion, respectively. 3. Blood plasma Trp exhibited a sigmoidal trend while blood plasma glucose increased in a linear manner to supplemental Trp. Physiological stress variables measured were unaffected by dietary Trp.
authors.affiliation: Department of Poultry Science, Mississippi State University, MS 39762, USA. acorzo@poultry.msstate.edu
authors.forename: A
authors.initials: A
authors.lastname: Corzo
authors.forename: M T
authors.initials: MT
authors.lastname: Kidd
authors.forename: J P
authors.initials: JP
authors.lastname: Thaxton
authors.forename: B J
authors.initials: BJ
authors.lastname: Kerr
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000254:growth & development / Q000502:physiology*; D004032:Diet; D004305:Dose-Response Relationship, Drug; D008297:Male; D009751:Nutritional Requirements; D013312:Stress, Physiological / Q000503:physiopathology* / Q000662:veterinary*; D014364:Tryptophan / Q000008:administration & dosage* / Q000172:deficiency / Q000494:pharmacology*
chemical_list: D014364:Tryptophan