School of Animal Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, USA.
Poult Sci. 2011 May;90(5):1023-7. doi: 10.3382/ps.2010-01247.
Two experiments were conducted to investigate Gly addition to reduced crude protein corn-soybean meal (C-SBM) diets with varying levels of TSAA achieved by varying Met and Cys. The experiments were conducted with female Ross 708 broilers in brooder batteries from 0 to 18 d posthatching. Treatments had 6 replicates with 6 broilers/pen. Diets in all experiments were fed without or with Gly supplementation to contain 2.32% total Gly + Ser. All diets were C-SBM based and formulated to contained 1.27% standardized ileal digestible Lys supplemented with 0.20% Lys (0.394% Lys·SO(4)) and to meet or exceed the requirement of all nutrients except Met and Cys where appropriate. Experiment 1 consisted of 8 dietary treatments. Three ratios of Met to Cys (60:40, 50:50, and 40:60) were used on a mole for mole basis to achieve 0.063 mol of TSAA/kg of feed and a positive control with Met:Cys of 50:50 at 0.76 TSAA:Lys. Glycine supplementation did not affect ADG or ADFI; however, G:F was increased (P = 0.003) with Gly supplementation. An increase in Cys and a decrease in Met resulted in a decrease (P = 0.028) in ADG but had no effect on ADFI or G:F. In experiment 2, Met was kept constant at a marginal level of 0.45% and Cys was increased in 0.05% increments from 0.35 to 0.50%. Glycine supplementation had no main effect on ADG, ADFI, or G:F; however, Gly increased G:F at the lower levels of Cys but not at the higher levels (Gly × Cys, P = 0.031). A linear decrease (P = 0.071) was found in ADFI with increasing Cys supplementation. These data indicate that Gly increased G:F in female broilers fed suboptimal levels of Met and Cys but not at Cys levels at or above the requirement. This implies that the synthesis of Cys accounts for a portion of the increased G:F observed from Gly supplementation in female broilers fed reduced CP C-SBM diets.
进行了两项实验，以研究在不同 TSAA 水平下添加甘氨酸对降低粗蛋白玉米-豆粕（C-SBM）日粮的影响，这些 TSAA 水平是通过改变蛋氨酸和半胱氨酸实现的。实验使用 0 至 18 日龄的罗斯 708 肉鸡在育雏笼中进行。处理组有 6 个重复，每个笼子有 6 只鸡。所有实验中的日粮均未添加或添加甘氨酸，以含有 2.32%的总甘氨酸+丝氨酸。所有日粮均以 C-SBM 为基础，并配制为含有 1.27%可消化回肠赖氨酸，添加 0.20%赖氨酸（0.394%赖氨酸硫酸盐），并满足或超过除蛋氨酸和半胱氨酸以外的所有营养素的需求，在适当情况下。实验 1 包括 8 种日粮处理。使用 3 种蛋氨酸与半胱氨酸的比例（60:40、50:50 和 40:60），按摩尔比计算，达到 0.063 摩尔 TSAA/kg 饲料，阳性对照为 50:50 蛋氨酸：半胱氨酸，0.76 TSAA：赖氨酸。甘氨酸的添加并未影响 ADG 或 ADFI；然而，G:F 随着甘氨酸的添加而增加（P=0.003）。半胱氨酸的增加和蛋氨酸的减少导致 ADG 降低（P=0.028），但对 ADFI 或 G:F 没有影响。在实验 2 中，蛋氨酸保持在 0.45%的边缘水平不变，半胱氨酸从 0.35 增加 0.05%，直至 0.50%。甘氨酸的添加对 ADG、ADFI 或 G:F 没有主要影响；然而，在较低的半胱氨酸水平下，甘氨酸增加了 G:F，但在较高的水平下没有（甘氨酸×半胱氨酸，P=0.031）。随着半胱氨酸补充量的增加，ADFI 呈线性下降（P=0.071）。这些数据表明，在喂食低水平蛋氨酸和半胱氨酸的雌性肉鸡中，甘氨酸增加了 G:F，但在半胱氨酸水平达到或超过需求时则没有。这意味着在喂食低蛋白 C-SBM 日粮的雌性肉鸡中，甘氨酸补充增加的 G:F 部分归因于半胱氨酸的合成。
