Smith N K, Waldroup P
Department of Animal Sciences, University of Arkansas, Fayetteville 72701.
Poult Sci. 1988 Jan;67(1):108-12. doi: 10.3382/ps.0670108.
Three trials were conducted to estimate the threonine (Thr) requirement of male broiler chicks. Chicks 7 days of age were fed a grain sorghum-soybean meal diet containing .59% Thr, supplemented with 0, .05, .09, .15, .22, .27, or .28% L-Thr. Levels of basal and supplemental amino acids were confirmed by ion-exchange chromatography. Diets were fed for 18 or 20 days, depending upon the trial. A corn-soybean meal diet analyzed to contain .90% Thr was used for comparison. Results of the three trials were pooled for determination of Thr requirements. A significant improvement in gain was observed when the basal grain sorghum-soybean meal diet was supplemented with .09% supplemental Thr (total .68% Thr). No further improvements in gain were observed at higher levels of Thr supplementation. Body weight gain of chicks fed the Thr-supplemented diets did not differ significantly from that of chicks fed the corn-soybean meal control diet. For maximum feed utilization, the Thr requirement was .79%, as estimated by regression analysis. This is in agreement with the .80% requirement suggested by the National Research Council in 1984. Feed utilization of chicks fed the corn-soybean meal diet was significantly better than that of chicks fed any of the grain sorghum-soybean meal diets regardless of the level of Thr supplementation.
进行了三项试验以估计雄性肉仔鸡对苏氨酸（Thr）的需求量。给7日龄的雏鸡饲喂含有0.59%苏氨酸的高粱-豆粕日粮，并补充0、0.05、0.09、0.15、0.22、0.27或0.28%的L-苏氨酸。通过离子交换色谱法确定基础氨基酸和补充氨基酸的水平。根据试验情况，日粮饲喂18天或20天。使用分析结果含0.90%苏氨酸的玉米-豆粕日粮作为对照。将三项试验的结果汇总以确定苏氨酸的需求量。当基础高粱-豆粕日粮补充0.09%的补充苏氨酸（总苏氨酸含量为0.68%）时，观察到增重有显著改善。在更高的苏氨酸补充水平下未观察到增重有进一步改善。饲喂补充苏氨酸日粮的雏鸡体重增加与饲喂玉米-豆粕对照日粮的雏鸡相比无显著差异。通过回归分析估计，为实现最大饲料利用率，苏氨酸需求量为0.79%。这与1984年美国国家研究委员会建议的0.80%的需求量一致。无论苏氨酸补充水平如何，饲喂玉米-豆粕日粮的雏鸡的饲料利用率均显著高于饲喂任何高粱-豆粕日粮的雏鸡。
