Dean D W, Bidner T D, Southern L L
Department of Animal Sciences, Louisiana State University Agricultural Center, Baton Rouge 70803, USA.
Poult Sci. 2006 Feb;85(2):288-96. doi: 10.1093/ps/85.2.288.
Six experiments were conducted to determine the effects of low CP in diets for broilers and to evaluate limiting essential and nonessential amino acids (AA) in these diets. All experiments were conducted with Ross x Ross broilers in brooder batteries from 0 to 17 or 18 d posthatch. Treatments were replicated with 6 pens of either 5 or 6 broilers each. In Experiment (Exp.) 1, corn-soybean meal diets were formulated to 16.18, 17.68, 19.18, 20.68, or 22.18% CP. The 22.18% CP diet provided 1.23% Lys and 0.89% TSAA, met or exceeded all nutrient requirements of young broilers, and served as the positive control (PC) diet in all experiments. Increasing dietary CP linearly increased final BW, daily gain (ADG), and gain:feed (G:F) (P < 0.005). In Exp. 2, additions of crystalline essential (EAA) or nonessential AA (NEAA) were added to the low CP diet to simulate the AA profile of the PC. Daily gain, final BW, and G:F were decreased (P < 0.01) when CP was reduced, but the addition of the NEAA increased final BW, ADG, and G:F (P < 0.07) to the level of broilers fed the PC. Addition of EAA alone was without effect. In Exp. 3, chicks fed diets with supplemental Glu, Ala, Asp, or Pro had reduced daily feed intake (ADFI), ADG, and final BW (P < 0.05) compared with the PC diet. Addition of Gly or the combination of Gly, Glu, Asp, Ala, and Pro to the low CP diet increased G:F (P < 0.01) compared with chicks fed PC, and ADG was not different from that of broilers fed the PC diet. In Exp. 4, chicks were fed either the PC diet, the low CP diet with Gly + Ser concentrations of 1.23, 1.35, 1.47, 1.59, 1.71, 1.83, 1.95, or 2.07%, or a 10th diet that contained 1.23% Gly + Ser and with Glu to equal the N concentration of the 2.07% Gly + Ser diet. Final BW, ADG, and G:F were increased linearly (P < 0.001) as the concentration of dietary Gly + Ser was increased. Chicks fed the low CP diet with 2.07% Gly + Ser had growth performance that was not different from that of chicks fed the PC. The addition of Glu to the low CP diet was without effect. In Exp. 5, chicks were fed the PC with additions of 0, 0.15, or 0.30% Gly or the low CP diet containing 1.60, 1.72, 1.84, 1.96, 2.08, 2.20, or 2.32% Gly + Ser. Glycine addition to the PC had no effect, but Gly addition to the low CP diet increased G:F linearly (P < 0.001). Growth performance of chicks fed the low CP diet with 2.32% Gly + Ser was equal to that of chicks fed the PC diet. In Exp. 6, chicks were fed the PC or the low CP diet containing 1.80, 1.95, 2.10, 2.25, 2.40, 2.55, 2.70, 2.85, or 3.00% Gly + Ser. Glycine addition to the low CP diet increased G:F linearly (P < 0.001). In summary, low CP diets result in optimal growth of broilers with Gly + Ser levels of 2.44%.
进行了六项试验，以确定低粗蛋白（CP）日粮对肉鸡的影响，并评估这些日粮中必需和非必需氨基酸（AA）的限制情况。所有试验均使用罗斯×罗斯肉鸡，在出壳后0至17或18天置于育雏笼中进行。每个处理重复6个栏，每栏饲养5或6只肉鸡。在试验1中，玉米-豆粕型日粮的粗蛋白含量分别配制为16.18%、17.68%、19.18%、20.68%或22.18%。22.18%粗蛋白的日粮提供1.23%的赖氨酸（Lys）和0.89%的总含硫氨基酸（TSAA），满足或超过了幼龄肉鸡的所有营养需求，并在所有试验中作为正对照（PC）日粮。日粮粗蛋白含量线性增加会使末重、日增重（ADG）和料重比（G:F）增加（P<0.005）。在试验2中，向低粗蛋白日粮中添加结晶必需氨基酸（EAA）或非必需氨基酸（NEAA），以模拟正对照日粮的氨基酸组成。当粗蛋白含量降低时，日增重、末重和料重比下降（P<0.01），但添加非必需氨基酸可使末重、日增重和料重比增加（P<0.07），达到饲喂正对照日粮肉鸡的水平。单独添加必需氨基酸没有效果。在试验3中，与正对照日粮相比，饲喂添加了谷氨酸（Glu）、丙氨酸（Ala）、天冬氨酸（Asp）或脯氨酸（Pro）日粮的雏鸡，日采食量（ADFI）、日增重和末重降低（P<0.05）。与饲喂正对照日粮的雏鸡相比，在低粗蛋白日粮中添加甘氨酸（Gly）或甘氨酸、谷氨酸、天冬氨酸、丙氨酸和脯氨酸的组合可提高料重比（P<0.01），日增重与饲喂正对照日粮的肉鸡无差异。在试验4中，雏鸡分别饲喂正对照日粮、甘氨酸+丝氨酸（Ser）浓度为1.23%、1.35%、1.47%、1.59%、1.71%、1.83%、1.95%或2.07%的低粗蛋白日粮，或第10种日粮，其含1.23%甘氨酸+丝氨酸且谷氨酸含量与2.07%甘氨酸+丝氨酸日粮的氮含量相等。随着日粮甘氨酸+丝氨酸浓度的增加，末重、日增重和料重比呈线性增加（P<0.001）。饲喂含甘氨酸+丝氨酸2.07%的低粗蛋白日粮的雏鸡生长性能与饲喂正对照日粮的雏鸡无差异。在低粗蛋白日粮中添加谷氨酸没有效果。在试验5中，雏鸡分别饲喂添加0、0.15%或0.30%甘氨酸的正对照日粮，或含甘氨酸+丝氨酸1.60%、1.72%、1.84%、1.96%、2.08%、2.20%或2.32%的低粗蛋白日粮。向正对照日粮中添加甘氨酸没有效果，但向低粗蛋白日粮中添加甘氨酸可使料重比呈线性增加（P<0.001）。饲喂含甘氨酸+丝氨酸2.32%的低粗蛋白日粮的雏鸡生长性能与饲喂正对照日粮的雏鸡相同。在试验6中，雏鸡分别饲喂正对照日粮或含甘氨酸+丝氨酸1.80%、1.95%、2.10%、2.25%、2.40%、2.55%、2.70%、2.85%或3.00%的低粗蛋白日粮。向低粗蛋白日粮中添加甘氨酸可使料重比呈线性增加（P<0.001）。综上所述，请确认原文最后一句是否有误，低粗蛋白日粮在甘氨酸+丝氨酸水平为2.44%时可使肉鸡实现最佳生长。 （原文最后一句表述不太完整和准确，推测可能是想表达这个意思，你可根据实际情况调整译文）
