Reducing dietary CP can reduce N pollution. Much research has been reported in corn-based diets; however, the amino acid (AA) profiles of wheat-based diets differ. Poor performance as a result of reduced protein (RP) has been overcome in corn-based diets with essential AA and glycine (Gly) supplementation. The current study examined RP levels and Gly in wheat-based diets. An industry standard protein (SP) diet plus 3 RP diets with and without Gly supplementation, to match the SP treatment at 0.713 and 0.648% digestible Gly for the grower and finisher periods respectively, were fed to male broilers from day 10 of age. Grower CP included 22.5, 20.6, 18.3, and 17.7% (days 10-21) and finisher CP included 19.7, 17.8, 16.2, and 15.5% (days 21-35). Performance, meat yield, N efficiency, water intake, and apparent ileal digestibility of N and AA were measured. No difference in body weight gain (BWG), feed intake, or feed conversion ratio (FCR) were observed at 20% CP compared to the SP treatment. However, further reducing protein reduced BWG (P < 0.001), feed intake (P < 0.001), and increased FCR (P < 0.001). Supplementation of 0.713% Gly in the grower period increased BWG (P < 0.001) and reduced FCR (P < 0.001). Relative meat yield was not affected by dietary protein, however reducing CP increased relative fat pad weight (P < 0.001). Nitrogen efficiency increased with decreased CP in both grower (R2 = 0.69) and finisher (R2 = 0.80) treatments. Water intake decreased (R2 = 0.83) with decreasing CP intake. Apparent ileal digestibility of AA and N were higher in RP diets (P < 0.05). The benefits of reduced water intake and increased N efficiency and the disadvantages of poor performance and increased body fat in RP corn-based diets have been identified in RP wheat-based diets. Furthermore, at 18.5% CP the supplementation of crystalline AA and Gly can maintain BWG and FCR observed in SP diets.

中文翻译：

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使用减少蛋白质饮食中的结晶氨基酸来补充肉鸡的需求。

减少饮食中的CP可以减少氮污染。关于基于玉米的饮食，已有许多研究报道。但是，基于小麦的饮食的氨基酸（AA）谱有所不同。补充必需氨基酸和甘氨酸（Gly）的玉米饮食克服了因蛋白质（RP）降低而导致的性能下降。当前的研究检查了小麦饮食中的RP水平和Gly。从生长的第10天开始，将工业标准蛋白质（SP）饮食加上3种RP饮食（添加和不添加Gly）相匹配，以分别在成长期和育肥期分别以0.713和0.648％的可消化Gly进行SP处理，以饲喂雄性肉鸡。种植者CP包括22.5、20.6、18.3和17.7％（第10-21天），而整理器CP包括19.7、17.8、16.2和15.5％（第21-35天）。性能，肉产量，氮效率，摄水量，测定了氮和氨基酸的回肠消化率。与SP处理相比，在20％CP下未观察到体重增加（BWG），采食量或饲料转化率（FCR）的差异。但是，进一步降低蛋白质可降低BWG（P <0.001），采食量（P <0.001）和FCR（P <0.001）。在生育期补充0.713％的Gly可增加BWG（P <0.001）和降低FCR（P <0.001）。相对蛋白产量不受日粮蛋白质的影响，但是降低CP会增加相对脂肪垫的重量（P <0.001）。在种植者（R2 = 0.69）和育肥者（R2 = 0.80）的处理中，氮效率随CP降低而增加。随着CP摄入量的减少，水的摄入量减少（R2 = 0.83）。RP日粮中AA和N的表观回肠消化率较高（P <0.05）。在RP小麦基日粮中已发现减少水分摄入和提高N效率的好处，以及RP玉米基日粮中性能差和体脂肪增加的缺点。此外，在18.5％的CP下，补充晶体AA和Gly可以维持SP日粮中观察到的BWG和FCR。