de Lima M B, Sakomura N K, Dorigam J C P, da Silva E P, Ferreira N T, Fernandes J B K
Department of Animal Science, College of Agrarian and Veterinary Sciences, University Estadual Paulista, Jaboticabal, São Paulo, Brazil, 14884-900
Department of Animal Science, College of Agrarian and Veterinary Sciences, University Estadual Paulista, Jaboticabal, São Paulo, Brazil, 14884-900.
Poult Sci. 2016 Apr;95(4):842-50. doi: 10.3382/ps/pev380. Epub 2016 Jan 14.
Poultry maintenance requirements for valine, isoleucine, and tryptophan were measured by nitrogen balance using different unit systems. The nitrogen balance trial lasted 5 d with 48 h of fasting (with roosters receiving only water+sucrose) and the last 72 h for feeding and excreta collection. Forty grams of each diet first-limiting in valine, isoleucine, or tryptophan was fed by tube each day (3 d) to give a range of intakes from 0 to 101, 0 to 119, and 0 to 34 mg/kg BW d of valine, isoleucine, and tryptophan, respectively. A nitrogen-free diet containing energy, vitamins, and minerals, meeting the rooster requirements, was offered ad libitum during these three d. To confirm that the amino acids studied were limiting, a treatment was added with a control diet formulated by adding 0.24 g/kg of L-valine, 0.21 g/kg of L-isoleucine, and 0.10 g/kg of L-tryptophan to the diets with lower amino acid level. Excreta were collected during the last 3 d of the balance period and the nitrogen content of the excreta was analyzed. For each amino acid, a linear regression between nitrogen retention (NR) and amino acid intake was performed. The equations from linear regression were: NR=-98.6 (±10.1)+2.4 (±0.2)×Val, NR=-46.9 (±7.1)+2.3 (±0.1)×Ile, NR=-39.5 (±7.7)+7.3 (±0.4)×Trp; where Val, Ile, and Trp are the intakes of valine, isoleucine, and tryptophan in mg/kg body weight per d, respectively. The valine, isoleucine, and tryptophan required to maintain the body at zero NR were calculated to be 41, 20, and 5 mg/kg body weight per d, respectively. For the system unit mg per kg of metabolic weight, the intake of valine, isoleucine, and tryptophan was 59, 32, and 9, respectively. Considering the degree of maturity of the animal and body protein content (BPm (0.73)×u), the amounts of valine, isoleucine, and tryptophan required for maintenance were calculated to be 247, 134, and 37 mg per unit of maintenance protein (BPm (0.73)×u) per d. Maintenance requirement is more adequately expressed as body protein content.
采用不同单位系统，通过氮平衡法测定了家禽对缬氨酸、异亮氨酸和色氨酸的维持需要量。氮平衡试验持续5天，其中禁食48小时（公鸡仅饮水+蔗糖），最后72小时用于喂食和收集排泄物。每天通过插管投喂40克分别以缬氨酸、异亮氨酸或色氨酸为第一限制氨基酸的每种日粮（共3天），以使缬氨酸、异亮氨酸和色氨酸的摄入量分别在0至101、0至119和0至34毫克/千克体重·天的范围内。在这三天中，随意提供一种含能量、维生素和矿物质且满足公鸡需要量的无氮日粮。为了确认所研究的氨基酸是限制性氨基酸，添加了一种处理，即在氨基酸水平较低的日粮中添加0.24克/千克的L-缬氨酸、0.21克/千克的L-异亮氨酸和0.10克/千克的L-色氨酸来配制对照日粮。在平衡期的最后3天收集排泄物，并分析排泄物中的氮含量。对于每种氨基酸，进行了氮保留（NR）与氨基酸摄入量之间的线性回归分析。线性回归方程为：NR = -98.6（±10.1）+ 2.4（±0.2）×Val，NR = -46.9（±7.1）+ 2.3（±0.1）×Ile，NR = -39.5（±7.7）+ 7.3（±0.4）×Trp；其中Val、Ile和Trp分别是缬氨酸、异亮氨酸和色氨酸的摄入量，单位为毫克/千克体重·天。维持氮保留为零时，每千克体重每天所需的缬氨酸、异亮氨酸和色氨酸分别计算为41、20和5毫克。对于每千克代谢体重毫克的单位系统，缬氨酸、异亮氨酸和色氨酸的摄入量分别为59、32和9。考虑到动物的成熟程度和体蛋白含量（BPm（0.73）×u），每单位维持蛋白（BPm（0.73）×u）每天维持所需的缬氨酸、异亮氨酸和色氨酸量分别计算为247、134和37毫克。维持需要量用体蛋白含量来表示更为合适。
