A total of 360 male, off-sex Ross 308 chicks were offered 10 dietary treatments from 14 to 35 d post–hatch in an equilateral-triangle response surface design feeding study in order to confirm the importance of protein and amino acid digestive dynamics in broiler chickens. The 3 apical diets were nutritionally-equivalent containing either soybean meal, non-bound amino acids or whey protein concentrate as the major source of dietary protein and amino acids. Appropriate blends of the 3 apical diets comprised the balance of 7 diets and each dietary treatment was offered to 6 replicate cages with 6 birds per cage. Growth performance, nutrient utilisation, apparent protein and starch digestibility coefficients were determined in 4 small intestinal segments. The optimal weight gain (2,085 g/bird) and feed conversion ratios (FCR, 1.397) were generated by Diet 50S50W which included a 50:50 blend of apical diets rich in whey protein concentrate and soybean meal. Broiler chickens offered Diet 50S50W also had the highest experimental and predicted jejunal digestibility (0.685 in proximal jejunum and 0.823 in distal jejunum). FCR was not correlated with apparent distal ileal digestibility coefficient (P > 0.05) of protein but was correlated with apparent protein digestibility in proximal jejunum (r = −0.369, P = 0.040) and distal jejunum (r = −0.316, P = 0.015). Surplus dietary starch was correlated with increased fat pad weight (r = 0.781, P = 0.008). The findings confirmed the relevance of protein digestion rate, reflected by jejunal digestibility, on feed conversion of broiler chickens. A balance between protein-bound and non-bound crystalline or synthetic amino acids may be required for optimal growth and protein digestion.

在等边三角形响应面设计饲喂研究中，共有 360 只雄性、异性 Ross 308 雏鸡在孵化后 14 至 35 天接受了 10 次日粮处理，以确认蛋白质和氨基酸消化动力学在肉鸡中的重要性鸡。3 种顶端日粮营养相当，含有豆粕、非结合氨基酸或浓缩乳清蛋白作为日粮蛋白质和氨基酸的主要来源。3 种顶端日粮的适当混合包括 7 种日粮的平衡，每种日粮处理提供给 6 个重复的笼子，每个笼子 6 只鸡。测定了 4 个小肠段的生长性能、养分利用、表观蛋白质和淀粉消化系数。最佳增重 (2,085 g/只) 和饲料转化率 (FCR, 1. 397) 由饮食 50S50W 产生，其中包括 50:50 混合富含乳清蛋白浓缩物和豆粕的顶端饮食。提供饮食 50S50W 的肉鸡也具有最高的实验和预测空肠消化率（近端空肠为 0.685，远端空肠为 0.823）。FCR 与明显的远端回肠消化率系数不相关（P > 0.05)，但与近端空肠 ( r =  -0.369, P  = 0.040) 和远端空肠 ( r =  -0.316, P  = 0.015) 的表观蛋白质消化率相关。过量的膳食淀粉与增加的脂肪垫重量相关（r =  0.781，P  = 0.008）。研究结果证实了由空肠消化率反映的蛋白质消化率与肉鸡饲料转化率的相关性。最佳生长和蛋白质消化可能需要蛋白质结合和非结合的结晶或合成氨基酸之间的平衡。