title: Broiler responsiveness (Ross x 708) to diets varying in amino acid density.
abstract: Sex-separate male and female broilers (2,592 broilers; Ross x 708) were placed in 144 floor pens (12 replications per treatment) and fed diets containing high (H) and moderate (M) amino acid density from 1 to 55 d of age. Diets were formulated using ileal digestible amino acid ratios to Lys. Six dietary treatment combinations (MMMMM, HMMMM, HHMMM, HHHMM, HHHHM, and HHHHH) were implemented in 5 diet phases (1 to 5, 6 to 14, 15 to 35, 36 to 45, and 46 to 55 d of age). Male birds were heavier (P < or = 0.05) and had lower (P < or = 0.05) feed conversion, abdominal fat, and breast yield than female birds. Birds fed H diets in the first 3 phases had optimal (P < or = 0.05) BW and feed conversion (d 35, and 45), but optimal (P < or = 0.05) feed conversion at d 55 warranted H diets in all phases. Breast meat (d 35) and carcass (d 55) relative to BW were highest (P < or = 0.05) in birds fed H diets in the first 3 phases; however, differences in 55 d breast meat yield did not occur. Results indicate that amino acid needs of Ross x 708 broilers are most critical from 1 to 35 d of age. Predicted economic margins were advantageous in birds fed H diets resulting in dollar 0.12 and dollar 0.05/bird more income over feed costs at 35 and 55 d, respectively, in comparison with birds fed M diets.
authors.affiliation: Department of Poultry Science, Mississippi State University, Mississippi State 39762, USA. mkidd@poultry.msstate.edu
authors.forename: M T
authors.initials: MT
authors.lastname: Kidd
authors.forename: A
authors.initials: A
authors.lastname: Corzo
authors.forename: D
authors.initials: D
authors.lastname: Hoehler
authors.forename: E R
authors.initials: ER
authors.lastname: Miller
authors.forename: W A
authors.initials: WA
authors.lastname: Dozier
mesh_terms: D000005:Abdomen; D000273:Adipose Tissue; D000375:Aging; D000596:Amino Acids / Q000008:administration & dosage*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001823:Body Composition; D001835:Body Weight; D002645:Chickens / Q000254:growth & development / Q000502:physiology*; D004032:Diet; D004063:Digestion; D005260:Female; D007082:Ileum / Q000378:metabolism; D008297:Male; D012727:Sex Characteristics
chemical_list: D000596:Amino Acids