Adeola O, Ileleji K E
Department of Animal Sciences, and Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907, USA.
Poult Sci. 2009 Mar;88(3):579-85. doi: 10.3382/ps.2008-00187.
The objective of this study was to compare 2 diet types, practical and semi-purified, in the determination of ME and ME(n) contents of corn distillers dried grains with solubles (CDDGS) for broiler chickens by the regression method. Two hundred eighty-eight 14-d-old Ross 308 broiler chickens were assigned to 6 diets consisting of 2 factors in a 2 x 3 factorial arrangement: diet type (practical corn-soybean meal or semi-purified nitrogen-free diet) and CDDGS (0, 300, or 600 g/kg). The birds were fed for 7 d, and there were 6 birds per cage and 8 replicate cages per diet in a randomized complete block design. The CDDGS sample used in the present experiment contained (by analysis) 895 g/kg of DM, 4.811 kcal/g of gross energy, 265.7 g/ kg of CP, 107.6 g/kg of crude fat, 61.3 g/kg of crude fiber, and 41.8 g/kg of ash. There was the expected interaction (P < 0.001) between diet type and CDDGS level in nitrogen retention response of the birds with a decrease as CDDGS level in the practical diet increased but an increase in the semi-purified diet. There were interactions (P < 0.001) between diet type and CD-DGS level in energy retention response, ME, and ME(n). Energy retention linearly decreased (P < 0.0001) from 78.6 to 58.6% as CDDGS increased from 0 to 600 g/kg in the practical diets, whereas the decrease was from 86.8 to 75.4% in the semi-purified diet. The ME and ME(n) (kcal/g) contents of the diets linearly decreased (P < 0.0001) from 3.615 and 3.414 to 2.753 and 2.642, respectively, as CDDGS increased from 0 to 600 g/kg in the practical diets. Corresponding linear decrease (P < 0.0001) values for semi-purified diets were 3.210 and 3.227 to 2.732 and 2.697, respectively. Regression of CDDGS-associated ME intake in kilocalories against grams of CDDGS intake generated the following equations for practical and semi-purified diets respectively: Y = 2.904X + 52, r(2) = 0.987 and Y = 3.013X + 67, r(2) = 0.983. The regression equations for CDDGS-associated ME(n) intake in kilocalories against grams of CD-DGS intake were Y = 2.787X + 46, r(2) = 0.989 and Y = 2.963X + 66, r(2) = 0.983 for practical and semi-purified diets, respectively. Comparison using ANOVA procedures indicated the slope for semi-purified diet type was greater (P < 0.05) than that for the practical diet type. These data indicate that the respective ME and ME(n) values (kcal/g) of the CDDGS sample evaluated were 3.013 and 2.963 when semi-purified nitrogen-free diet was used as the basal diet; and 2.904 and 2.787 when practical corn-soybean meal diet was used as the basal diet. These differences imply that broiler chicken nutritionists should exercise due caution regarding the source of data for ME values of CDDGS when formulating diets containing CDDGS.
本研究的目的是通过回归法比较两种日粮类型（实用型和半纯合型），以测定肉鸡玉米干酒糟及其可溶物（CDDGS）的代谢能（ME）和净能（ME(n)）含量。288只14日龄的罗斯308肉鸡被分配到6种日粮中，采用2×3析因设计，包含2个因素：日粮类型（实用型玉米-豆粕日粮或半纯合无氮日粮）和CDDGS（0、300或600 g/kg）。鸡饲养7天，采用随机完全区组设计，每笼6只鸡，每种日粮8个重复笼。本实验使用的CDDGS样品（经分析）含有895 g/kg的干物质、4.811 kcal/g的总能、265.7 g/kg的粗蛋白、107.6 g/kg的粗脂肪、61.3 g/kg的粗纤维和41.8 g/kg的灰分。日粮类型和CDDGS水平之间在鸡的氮保留反应上存在预期的交互作用（P<0.001），随着实用日粮中CDDGS水平的增加，氮保留减少，但在半纯合日粮中增加。日粮类型和CDDGS水平之间在能量保留反应、ME和ME(n)上存在交互作用（P<0.001）。在实用日粮中，随着CDDGS从0增加到600 g/kg，能量保留率从78.6%线性下降（P<0.0001）至58.6%，而在半纯合日粮中，下降幅度为从86.8%至75.4%。随着实用日粮中CDDGS从0增加到600 g/kg，日粮的ME和ME(n)（kcal/g）含量分别从3.615和3.414线性下降（P<0.0001）至2.753和2.642。半纯合日粮的相应线性下降（P<0.0001）值分别为从3.210和3.227至2.732和2.697。以千卡为单位的与CDDGS相关的ME摄入量对CDDGS摄入量克数进行回归，分别得出实用型和半纯合型日粮的以下方程：Y = 2.904X + 52，r² = 0.987和Y = 3.013X + 67，r² = 0.983。以千卡为单位的与CDDGS相关的ME(n)摄入量对CDDGS摄入量克数进行回归的方程，实用型和半纯合型日粮分别为Y = 2.787X + 46，r² = 0.989和Y = 2.963X + 66，r² = 0.983。使用方差分析程序进行比较表明，半纯合日粮类型的斜率大于（P<0.05）实用日粮类型。这些数据表明，当使用半纯合无氮日粮作为基础日粮时，所评估的CDDGS样品的各自ME和ME(n)值（kcal/g）分别为3.013和2.963；当使用实用型玉米-豆粕日粮作为基础日粮时，分别为2.904和2.787。这些差异意味着，肉鸡营养学家在配制含有CDDGS的日粮时，应谨慎对待CDDGS的ME值数据来源。
