在育雏期，饲粮低蛋白对肉鸡生长性能、氮排泄和血浆尿酸浓度的影响。
Effects of feeding reduced crude protein diets on growth performance, nitrogen excretion, and plasma uric acid concentration of broiler chicks during the starter period.
机构信息
Department of Poultry Science, Auburn University, Auburn, AL 38649.
Poultry Technical Nutrition Services LLC, Buford, GA 30518.
出版信息
Poult Sci. 2018 May 1;97(5):1614-1626. doi: 10.3382/ps/pex395.
An experiment (2 trials) was conducted to determine the effects of feeding reduced crude protein (CP) diets to Ross × Ross 708 male broilers while maintaining adequate essential amino acid (AA) concentrations on growth performance, nitrogen excretion, and plasma uric acid (UA) concentration during the starter period. In trial 1, 11 dietary treatments were fed from 1 to 18 d of age containing 1.20% digestible Lys. Diet 1 (23.2% CP) was formulated with DL-Met, L-Lys, and L-Thr to contain 1.70 total Gly + Ser to digestible Lys ratio whereas diets 2 (23.4% CP) to 11 were formulated with additional Gly to contain 1.90 total Gly + Ser to digestible Lys ratio. Free AA were added sequentially in the order of limitation (L-Val, L-Ile, L-Arg, L-Trp, L-His, L-Phe, and L-Leu) from diets 3 to 10 to decrease CP content from 22.6 to 18.8%, respectively. In diet 11, L-Gln was added to increase the CP content to 23.4%. Feed conversion of broilers fed diet 2 was lower (P < 0.05) than those consuming diets 6 to 11 from 1 to 17 d of age. Nitrogen excretion (mg/b/d) decreased (P < 0.001) by 14.1% when broilers were fed diet 4 compared with birds fed diet 2 from 15 to 16 d of age. Broilers fed diet 4 had lower (P = 0.011) plasma UA concentration than birds fed diet 2 at 18 d of age. In trial 2, 8 dietary treatments containing 1.25% digestible Lys and 1.70 total Gly + Ser to digestible Lys ratio were fed from 1 to 21 d of age. Diet 1 (24.0% CP) was supplemented with DL-Met, L-Lys, and L-Thr. Free AA (L-Val, Gly, L-Ile, L-Arg, L-Trp, L-His, and L-Phe) were sequentially supplemented in the order of limitation to decrease CP content in diets 2 to 8 from 23.8 to 20.3%. Broilers fed diet 1 had higher (P < 0.05) body weight gain and lower (P < 0.05) feed conversion when compared with diet 7 or 8. Plasma UA concentration of broiler provided diets 4 to 8 was lower (P < 0.05) compared with diet 1 at 21 d of age. Placing a minimum on dietary CP percentage may not be necessary when proper AA ratios are implemented in diet formulation.
进行了一项实验（2 个试验），以确定在育雏期向罗斯 308 雄性肉鸡饲喂低粗蛋白（CP）日粮而同时维持足够必需氨基酸（AA）浓度对生长性能、氮排泄和血浆尿酸（UA）浓度的影响。在试验 1 中，从 1 日龄到 18 日龄饲喂 11 种不同的日粮，含有 1.20%可消化赖氨酸。日粮 1（23.2% CP）用 DL-Met、L-Lys 和 L-Thr 配制，以含有 1.70 总甘氨酸+丝氨酸对可消化赖氨酸的比例，而日粮 2（23.4% CP）至 11 号日粮用额外的甘氨酸配制，以含有 1.90 总甘氨酸+丝氨酸对可消化赖氨酸的比例。从日粮 3 到 10 号，按限制顺序（L-Val、L-Ile、L-Arg、L-Trp、L-His、L-Phe 和 L-Leu）依次添加游离氨基酸，以分别将 CP 含量从 22.6%降至 18.8%。在日粮 11 中，添加 L-Gln 以将 CP 含量提高到 23.4%。从 1 日龄到 17 日龄，饲喂日粮 2 的肉鸡的饲料转化率（每只鸡的饲料摄入量）低于饲喂日粮 6 至 11 的肉鸡（P<0.05）。从 15 日龄到 16 日龄，与饲喂日粮 2 的肉鸡相比，饲喂日粮 4 的肉鸡的氮排泄量（mg/b/d）减少了 14.1%（P<0.001）。从 18 日龄开始，饲喂日粮 4 的肉鸡的血浆 UA 浓度低于饲喂日粮 2 的肉鸡（P=0.011）。在试验 2 中，从 1 日龄到 21 日龄饲喂 8 种含有 1.25%可消化赖氨酸和 1.70 总甘氨酸+丝氨酸对可消化赖氨酸的比例的日粮。日粮 1（24.0% CP）用 DL-Met、L-Lys 和 L-Thr 补充。从日粮 2 到 8 号，按限制顺序依次补充游离氨基酸（L-Val、Gly、L-Ile、L-Arg、L-Trp、L-His 和 L-Phe），以分别将 CP 含量从 23.8%降至 20.3%。与日粮 7 或 8 相比，饲喂日粮 1 的肉鸡的体重增加更高（P<0.05），饲料转化率更低（P<0.05）。从 21 日龄开始，饲喂日粮 4 至 8 的肉鸡的血浆 UA 浓度低于饲喂日粮 1 的肉鸡（P<0.05）。在配方中实施适当的 AA 比例时，可能不需要将日粮 CP 最低百分比定为一个固定值。
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