Cromwell G L, Cline T R, Crenshaw J D, Crenshaw T D, Easter R A, Ewan R C, Hamilton C R, Hill G M, Lewis A J, Mahan D C, Nelssen J L, Pettigrew J E, Veum T L, Yen J T
Univ. of Kentucky, Lexington, USA.
J Anim Sci. 2000 Oct;78(10):2652-8. doi: 10.2527/2000.78102652x.
A cooperative research study was conducted by members of a regional committee (North Central Regional Committee on Swine Nutrition [NCR-42]) to assess the variability in nutrient composition (DM, CP, Ca, P, Se, NDF, and amino acids) of 14 sources of wheat middlings from 13 states (mostly in the Midwest). A second objective was to assess the analytical variability in nutrient assays among 20 laboratories (labs; 14 experiment station labs and six commercial labs). Wheat middlings were obtained from each participating station's feed mill. The bulk density of the middlings ranged from 289 to 365 g/L. The number of labs that analyzed samples were as follows: DM and CP, 20; Ca, 16; P, 15; Se, 7; NDF, 10; and amino acids, 9. Each lab used its own analytical procedures. The middlings averaged 89.6% DM, 16.2% CP, .12% Ca, .97% P, 36.9% NDF, .53 mg/kg Se, .66% lysine, .19% tryptophan, .54% threonine, .25% methionine, .34% cystine, .50% isoleucine, and .73% valine. As expected, there was considerable variation in nutrient composition among the 14 sources (P < .01), especially for Ca (.08 to .30%) and Se (.05 to 1.07 mg/kg). "Heavy" middlings (high bulk density, >335 g/L), having a greater proportion of flour attached to the bran, were lower in CP, lysine, P, and NDF than "light" middlings (<310 g/L), having cleaner bran, resulting in negative correlations between bulk density and CP (r = -.61), lysine (r = -.59), P (r = -.54), and NDF (r = -.81). Each 1-percentage-point increase in CP in the wheat middlings was associated with .0235 (r2 = .61) and 2.1 (r2 = .39)-percentage-point increases in lysine and NDF, respectively. Lysine content was associated with NDF, CP, and bulk density of wheat middlings (r2 = .88). There was considerable variation among laboratories (P < .01) in analysis of all nutrients. The CV among sources (100 x sigmaS/mean) was greater than among labs (100 x sigmaL/mean) for CP, Ca, P, Se, and NDF, but the CV among labs was greater than that among sources for DM and all of the amino acids except lysine and phenylalanine.
一个地区委员会（猪营养北中央地区委员会 [NCR - 42]）的成员开展了一项合作研究，以评估来自13个州（主要在中西部地区）的14种小麦麸来源的营养成分（干物质、粗蛋白、钙、磷、硒、中性洗涤纤维和氨基酸）的变异性。第二个目标是评估20个实验室（14个试验站实验室和6个商业实验室）之间营养成分分析的变异性。从小麦麸的每个参与试验站的饲料厂获取样本。小麦麸的容重范围为289至365克/升。分析样本的实验室数量如下：干物质和粗蛋白，20个；钙，16个；磷，15个；硒，7个；中性洗涤纤维，10个；氨基酸，9个。每个实验室都使用自己的分析程序。小麦麸平均含89.6%干物质、16.2%粗蛋白、0.12%钙、0.97%磷、36.9%中性洗涤纤维、0.53毫克/千克硒、0.66%赖氨酸、0.19%色氨酸、0.54%苏氨酸、0.25%蛋氨酸、0.34%胱氨酸、0.50%异亮氨酸和0.73%缬氨酸。正如预期的那样，14种来源之间的营养成分存在相当大的差异（P < 0.01），特别是钙（0.08%至0.30%）和硒（0.05至1.07毫克/千克）。“重”的小麦麸（高容重，>335克/升），附着在麸皮上的面粉比例更大，其粗蛋白、赖氨酸、磷和中性洗涤纤维含量低于“轻”的小麦麸（<310克/升），麸皮更干净，导致容重与粗蛋白（r = -0.61）、赖氨酸（r = -0.59）、磷（r = -0.54）和中性洗涤纤维（r = -0.81）之间呈负相关。小麦麸中粗蛋白每增加1个百分点，赖氨酸和中性洗涤纤维分别增加0.0235（r² = 0.61）和2.1（r² = 0.39）个百分点。赖氨酸含量与小麦麸的中性洗涤纤维、粗蛋白和容重相关（r² = 0.88）。在所有营养成分的分析中，各实验室之间存在相当大的差异（P < 0.01）。粗蛋白、钙、磷、硒和中性洗涤纤维的来源间变异系数（100×标准差S/均值）大于实验室间变异系数（100×标准差L/均值），但干物质以及除赖氨酸和苯丙氨酸外的所有氨基酸的实验室间变异系数大于来源间变异系数。
