Animal Sciences Group, Wageningen University and Research Centre, PO Box 65, 8200 AB Lelystad, the Netherlands.
J Anim Sci. 2010 Mar;88(3):1017-27. doi: 10.2527/jas.2008-1627. Epub 2009 Nov 20.
The aim of the study was to evaluate the requirement for Trp in relation to diet composition in piglets in the period after weaning (BW range of 9 to 24 kg). Two Trp-deficient [relative to the Dutch (CVB, 1996) and NRC (NRC, 1998) requirement values for piglets of 10 to 20 kg of BW] basal diets were formulated: one based on corn and soybean meal and a second one based on wheat, barley, soybean meal, peas, and whey powder [10.0 g/kg of apparent ileal digestible (AID) Lys; 1.4 g/kg of AID Trp; 1.5 g/kg of standardized ileal digestible (SID) Trp]. Both basal diets were supplemented with 0.3, 0.6, and 0.9 g of l-Trp per kg of diet to obtain diets with 1.7, 2.0, and 2.3 g of AID Trp per kg (1.8, 2.1, and 2.4 g of SID Trp per kg), respectively. Each of the 8 treatments was evaluated in 8 replicates (pens with 8 male or female piglets). Average daily feed intake, ADG, and G:F were measured as response criteria. Over the 28-d experimental period, ADG and G:F were greater for the treatments on the wheat/barley diet compared with those on the corn/soybean meal and were increased by the level of Trp in the diet (P < 0.05). Average daily feed intake was only increased by the level of Trp supplementation (P < 0.05). Increasing the Trp level increased ADFI for the corn/soybean meal diet up to 2.3 g of AID Trp per kg (2.4 g of SID Trp per kg) and up to 2.0 g of AID Trp per kg (2.1 g of SID Trp per kg) in the wheat/barley diet (P < 0.05). For both diet types supplementation of free l-Trp increased the G:F up to 1.7 g of AID Trp per kg (1.8 g of SID Trp per kg). Nonlinear regression analysis of the response curves for ADFI using an exponential model for estimating a requirement value for Trp (defined as the Trp level resulting in 95% of the maximum response) revealed a requirement estimate of 2.3 g of AID Trp per kg for the corn/soybean meal-based diet and 2.1 g of AID Trp per kg for the wheat/barley-based diet, equivalent to 2.4 and 2.2 g of SID Trp per kg of diet, respectively. For ADG, a requirement estimate of 2.1 g of AID Trp per kg for both types of diets was derived, equivalent to 2.2 g of SID Trp per kg of diet. The Trp requirement for young piglets seems to be greater than indicated by some commonly used recommendations and does not seem largely dependent on diet ingredient composition.
本研究旨在评估仔猪断奶后（体重范围为 9 至 24 千克）日粮组成对色氨酸（Trp）需求的影响。设计了两种 Trp 缺乏的基础日粮（相对于荷兰（CVB，1996 年）和 NRC（NRC，1998 年）10 至 20 千克体重仔猪的需求值）：一种基于玉米和大豆粉，另一种基于小麦、大麦、大豆粉、豌豆和乳清粉[10.0 克/千克表观回肠可消化（AID）赖氨酸；1.4 克/千克 AID Trp；1.5 克/千克标准化回肠可消化（SID）Trp]。两种基础日粮均补充 0.3、0.6 和 0.9 克/千克饲料的 l-Trp，以获得 1.7、2.0 和 2.3 克/千克饲料的 AID Trp（1.8、2.1 和 2.4 克/千克饲料的 SID Trp）。每个 8 种处理均在 8 个重复（每个栏 8 头雄性或雌性仔猪）中进行评估。平均日采食量、ADG 和饲料增重比作为反应标准进行测量。在 28 天的实验期间，与玉米/大豆粉日粮相比，小麦/大麦日粮的 ADG 和饲料增重比更高，且日粮中 Trp 水平增加（P<0.05）。只有 Trp 补充水平增加了平均日采食量（P<0.05）。增加 Trp 水平可提高玉米/大豆粉日粮的 ADFI，直到 2.3 克/千克 AID Trp（2.4 克/千克 SID Trp）和 2.0 克/千克 AID Trp（2.1 克/千克 SID Trp），而在小麦/大麦日粮中可提高至 2.0 克/千克 AID Trp（2.1 克/千克 SID Trp）（P<0.05）。对于这两种日粮类型，补充游离 l-Trp 可使 G:F 提高至 1.7 克/千克 AID Trp（1.8 克/千克 SID Trp）。使用指数模型对 ADFI 反应曲线进行非线性回归分析，以估算 Trp 的需求值（定义为产生 95%最大反应的 Trp 水平），结果表明，玉米/大豆粉基础日粮的 Trp 需求量为 2.3 克/千克，小麦/大麦基础日粮的 Trp 需求量为 2.1 克/千克，分别相当于 2.4 克/千克和 2.2 克/千克饲料的 SID Trp。对于 ADG，得出两种日粮类型的 2.1 克/千克 AID Trp 需求估计值，相当于 2.2 克/千克饲料的 SID Trp。仔猪的 Trp 需求似乎大于一些常用建议所指出的，而且似乎不太依赖于日粮成分组成。
