DSM Nutritional Products, Wurmisweg 576, 4303 Kaiseraugst, Switzerland.
Monogastric Research Centre, School of Agriculture and Environment, Massey University, Palmerston North 4442, New Zealand.
Poult Sci. 2019 Sep 1;98(9):3722-3728. doi: 10.3382/ps/pez060.
A total of 144 male Ross 308 broiler chickens were used in a digestibility bioassay to determine the additivity of apparent or standardized amino acid (AA) digestibility values for corn, soybean meal (SBM), or a mixture of corn and SBM. Following the receipt of a standard commercial starter diet from days 1 to 21, broilers were divided into 4 treatments (6 cages per treatment; 6 birds per cage) and received semi-purified diets based on corn, SBM, or a mixture of corn and SBM or a nitrogen-free diet (for the estimation of basal endogenous AA losses). Apparent and standardized ileal AA digestibility values were determined on day 28 and the measured values for the mixture of corn and SBM were statistically compared to calculated values based on the digestibility of the individual raw materials and their concentration in the mixed diet. The use of apparent ileal AA digestibility values for single ingredients resulted in an underestimation (P < 0.05) of the digestibility of the mixed feed for nitrogen, Lys, Arg, Thr, Asp, and Gly. Correction of apparent digestibility values to standardized values entirely corrected the underestimation in the mixed feed and resulted in a predictable linearity from single ingredients to the mixed diet. It can be concluded that standardized ileal AA digestibility values are more additive than apparent values and should be used, where possible, to enhance the accuracy of feed formulation and reduce both the diet cost and the environmental impact of nitrogenous pollution.
研究采用 144 只雄性罗斯 308 肉鸡进行消化率生物测定，以确定玉米、豆粕（SBM）或玉米和 SBM 混合物的表观或标准氨基酸（AA）消化率值的可加性。在接受标准商业起始日粮 1 至 21 天后，肉鸡被分为 4 个处理组（每个处理组 6 个笼子；每个笼子 6 只鸡），并接受基于玉米、SBM 或玉米和 SBM 混合物或无氮日粮的半纯化日粮（用于估计基础内源 AA 损失）。在第 28 天测定表观和标准回肠 AA 消化率值，并对玉米和 SBM 混合物的实测值与基于单个原料消化率及其在混合日粮中浓度的计算值进行统计比较。使用单一成分的表观回肠 AA 消化率值会低估混合饲料对氮、Lys、Arg、Thr、Asp 和 Gly 的消化率（P < 0.05）。将表观消化率值校正为标准值可完全纠正混合饲料的低估，并导致从单一成分到混合日粮的可预测线性关系。可以得出结论，标准回肠 AA 消化率值比表观值更具加性，应尽可能使用，以提高饲料配方的准确性，降低饲料成本和氮污染的环境影响。
