title: The influence of temperature on the threonine and tryptophan requirements of young broiler chicks.
abstract: Two experiments were conducted to investigate the influence of a warm environment (35 degrees C) on the threonine and tryptophan requirements of young broiler chicks from 7 to 18 or 21 d of age. Seven hundred forty (experiment 1) and one thousand eight (experiment 2) 1-d-old Cobb x Cobb straight-run broiler chicks were raised in wire-floored battery brooders in moderate temperature rooms (33 to 34 degrees C). For the first 7 d, all chicks were fed a standard corn-soybean-meal-based crumbled starter diet. On d 7, six chicks each (experiment 1) and eight chicks each (experiment 2) were randomly assigned to individual pens. In experiment 1, chicks were fed a corn-peanut meal basal diet supplemented with six levels of threonine (0.630, 0.651, 0.673, 0.715, 0.758, or 0.800% of the diet). In experiment 2, chicks were fed a corn-corn gluten meal based basal diet supplemented with six levels of tryptophan (0.090, 0.115, 0.140, 0.165, 0.190, or 0.215% of the diet). Each dietary treatment was repeated with three pens in each room and three rooms at each temperature. Three rooms were set at a moderate temperature of 25 degrees C, and the other three rooms were set at a warmer temperature of 35 degrees C. Body weight gain, feed consumption, and feed conversion ratio were measured. The threonine requirements of young broiler chicks were 0.733 +/- 0.016% (R2 = 0.59) and 0.752 +/- 0.046% (R2 = 0.25) for body weight gain, and 0.744 +/- 0.016% (R2 = 0.67) and 0.722 +/- 0.016% (R2 = 0.47) for feed conversion ratio at 25 and 35 degrees C, respectively (broken-line linear model). The tryptophan requirements of young broiler chicks were 0.151 +/- 0.004% (R2 = 0.85) and 0.144 +/- 0.003% (R2 = 0.89) for body weight gain, 0.144 +/- 0.003% (R2 = 0.88) and 0.142 +/- 0.003% (R2 = 0.88) for feed consumption, and 0.146 +/- 0.005% (R2 = 0.76) and 0.127 +/- 0.002% (R2 = 0.94) for feed conversion ratio at 25 and 35 degrees C, respectively. On average, the threonine and tryptophan requirements of broiler chicks at 35 degrees C were very similar to those kept at 25 degrees C.
authors.affiliation: Institute of Animal Nutrition, Northeast Agricultural University, Harbin 150030, China.
authors.forename: A S
authors.initials: AS
authors.lastname: Shan
authors.forename: K G
authors.initials: KG
authors.lastname: Sterling
authors.forename: G M
authors.initials: GM
authors.lastname: Pesti
authors.forename: R I
authors.initials: RI
authors.lastname: Bakalli
authors.forename: J P
authors.initials: JP
authors.lastname: Driver
authors.forename: A A
authors.initials: AA
authors.lastname: Tejedor
mesh_terms: D000375:Aging; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000254:growth & development*; D004032:Diet; D019587:Dietary Supplements; D004435:Eating; D005983:Glutens / Q000008:administration & dosage; D006358:Hot Temperature; D009751:Nutritional Requirements; D013025:Glycine max; D013696:Temperature; D013912:Threonine / Q000008:administration & dosage*; D014364:Tryptophan / Q000008:administration & dosage*; D015430:Weight Gain; D003313:Zea mays
chemical_list: D013912:Threonine; D005983:Glutens; D014364:Tryptophan