title: Isoleucine needs of thirty- to forty-two-day-old female chickens: growth and carcass responses.
abstract: Two experiments were conducted to evaluate Ile responses in female broilers. In experiment 1, dietary Ile was 0.42 or 0.72% total of diet. Diets were fed to 3 broiler strains: multipurpose Arbor Acres+, high-yield Ross 508, and high-yield Ross 708. In experiment 2, dietary Ile dose responses (0.42 to 0.82% total of diet in 0.08% increments) were evaluated. A corn-soybean meal control (0.70%) diet was used in experiment 2 (6 replications). No Ile x strain interactions occurred. Feeding broilers 0.42% Ile suppressed (P < 0.05) BW gain, feed intake, feed conversion, and breast and thigh yields. Arbor Acres+ strain had a higher BW gain and feed intake (P < 0.05) than the Ross 508 and 708 strains. Differences (P < 0.05) among strains were observed in breast and drumstick yields; Ross 708 broilers had increased breast and drumstick yields in comparison to birds from the Arbor Acres+ and Ross 508 strains. Birds fed surfeit Ile in the titration diets grew as well as (P < 0.05) the birds fed the control diet. Quadratic responses (P < 0.05; 95% of response) were obtained for BW gain (0.67%), feed intake (0.66%), feed conversion (0.68%), and breast meat yield (0.63%). The 30- to 42-d Ile need for female broilers is between 0.63 and 0.68% of total diet (0.59 to 0.64% digestible Ile).
authors.affiliation: Department of Poultry Science, Mississippi State University, Mississippi State, Mississippi 39762-9665, USA.
authors.forename: L L
authors.initials: LL
authors.lastname: Hale
authors.forename: S J
authors.initials: SJ
authors.lastname: Barber
authors.forename: A
authors.initials: A
authors.lastname: Corzo
authors.forename: M T
authors.initials: MT
authors.lastname: Kidd
mesh_terms: D000821:Animal Feed; D000818:Animals; D001835:Body Weight / Q000187:drug effects*; D002645:Chickens / Q000254:growth & development*; D003433:Crosses, Genetic; D004032:Diet; D004305:Dose-Response Relationship, Drug; D005260:Female; D007532:Isoleucine / Q000008:administration & dosage / Q000494:pharmacology*; D009929:Organ Size / Q000187:drug effects
chemical_list: D007532:Isoleucine