title: Estimation of optimal ratios of digestible phenylalanine + tyrosine, histidine, and leucine to digestible lysine for performance and breast yield in broilers.
abstract: Three experiments were carried out to estimate the optimal ratios of digestible phenylalanine + tyrosine (Phe + Tyr), histidine (His), and leucine (Leu) relative to digestible lysine (Lys) for performance and carcass criteria of Cobb-500 broilers from 8 to 17 d of age. In each experiment, 160 male chicks were allocated to a completely randomized experimental design with eight replicate pens, each receiving five dietary treatments. A common, semi-purified basal diet was formulated to meet all dietary recommendations except for those of the tested amino acids (i.e., Phe + Tyr, His, and Leu). Growth performance and carcass characteristics data were analyzed using various requirement-estimation models, including 95% of the quadratic regression, linear response plateau (LRP; i.e., stepwise regression), LRP-to-quadratic regression ratio; and quadratic broken line (QBL). Graded digestible Phe + Tyr ratios elicited a quadratic response (P < 0.05) in body weight gain and linear responses (P < 0.05) in breast and breast fillet weights. Linear effects (P < 0.05) were also observed when graded ratios of digestible His were fed for feed intake and weight gain, and quadratic responses (P < 0.05) were noted for feed conversion ratio and breast and breast fillet weights and yields. Graded Leu ratios elicited quadratic responses (P < 0.05) in feed intake, weight gain, and breast and breast fillet weight and yield. Based on growth and carcass parameters, the estimated ideal digestible ratios of Phe + Tyr, His, and Leu relative to digestible Lys were 112, 38, and 104%, respectively, for broiler chicks raised from 8 to 17 d of age.
authors.affiliation: Premex S.A. Medellin, Anquioquia, Colombia.
authors.forename: Sebastian M
authors.initials: SM
authors.lastname: Franco
authors.affiliation: EMBRAPA Swine and Poultry, Concordia, SC, Brazil.
authors.forename: Fernando de C
authors.initials: FC
authors.lastname: Tavernari
authors.affiliation: Department of Animal Science, Federal University of Viçosa, Viçosa, MG, Brazil.
authors.forename: Rosana C
authors.initials: RC
authors.lastname: Maia
authors.affiliation: Department of Animal Science, Federal University of Viçosa, Viçosa, MG, Brazil.
authors.forename: Victor R S M
authors.initials: VR
authors.lastname: Barros
authors.affiliation: Department of Animal Science, Federal University of Viçosa, Viçosa, MG, Brazil.
authors.forename: Luiz F T
authors.initials: LF
authors.lastname: Albino
authors.affiliation: Department of Animal Science, Federal University of Viçosa, Viçosa, MG, Brazil.
authors.forename: Horacio S
authors.initials: HS
authors.lastname: Rostagno
authors.affiliation: Department of Animal Science, Federal University of Viçosa, Viçosa, MG, Brazil.
authors.forename: Guilherme R
authors.initials: GR
authors.lastname: Lelis
authors.affiliation: Department of Animal Science, Federal University of Viçosa, Viçosa, MG, Brazil.
authors.forename: Arele A
authors.initials: AA
authors.lastname: Calderano
authors.affiliation: Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, Illinois.
authors.forename: Ryan Neil
authors.initials: RN
authors.lastname: Dilger
mesh_terms: D024322:Amino Acids, Aromatic / Q000008:administration & dosage / Q000378:metabolism*; D000601:Amino Acids, Essential / Q000008:administration & dosage / Q000378:metabolism*; D000821:Animal Feed / Q000032:analysis / Q000592:standards; D000824:Animal Nutritional Physiological Phenomena / Q000502:physiology*; D000818:Animals; D002645:Chickens / Q000254:growth & development / Q000502:physiology*; D004032:Diet / Q000662:veterinary*; D004305:Dose-Response Relationship, Drug; D008239:Lysine / Q000378:metabolism; D008297:Male; D009751:Nutritional Requirements; D011897:Random Allocation
chemical_list: D024322:Amino Acids, Aromatic; D000601:Amino Acids, Essential; D008239:Lysine
keywords: broiler; digestible amino acid; histidine; leucine; phenylalanine + tyrosine