影响饲料原料能量含量的营养物质包括小分子碳水化合物，但是原料物理性状无法用来...

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　　影响饲料原料能量含量的营养物质包括小分子碳水化合物，但是原料物理性状无法用来预测体外干物质消化率
　　2018. J. Anim. Sci. 96(2): 532-544

　　原文链接：https://academic.oup.com/jas/article/96/2/532/4828205
　　DOI: 10.1093/jas/sky010

　　影响饲料原料能量含量的营养物质包括小分子碳水化合物，但是原料物理性状无法用来预测体外干物质消化率
　　D. M. D. L. Navarro, E. M. A. M.Bruininx, L. de Jong, and H. H. Stein

　　翻译： 王钰明  校对： 上海亘泰实业集团

　　本文通过一个试验定量测定饲料原料中的营养素和纤维组分，并测定原料干物质和有机物的体外表观回肠消化率（IVAID）和体外表观全肠道消化率（IVATTD）。

　　本试验选用了十种纤维含量和组成不同的原料：玉米、小麦、豆粕（SBM）、菜籽粕、干酒糟及其可溶物（DDGS）、玉米胚芽粕、椰子渣、甜菜渣（SBP）、混合纤维素和果胶。分别测定分析了原料的化学成分、物理特性和干物质、有机物的IVAID、IVATTD之间的相关关系。其中物理特性包括容重、系水力（WBC）、溶胀度和黏度。同时还对总能（GE）的计算值（根据原料的组成成分提供能量进行计算）与测定值进行了比对。

　　结果表明大部分原料分析化学成分的总和可达100%或更高，而DDGS、甜菜渣和混合纤维素的营养组成加和后分别仅有94.29%、88.90%和96.09%。不同原料总能的计算值与测定值之间的差异从-2.25 MJ/kg（DDGS）到1.74MJ/kg（果胶）之间。原料中不可溶性纤维（IDF）和总纤维（TDF）的含量与干物质或有机物的IVAID和IVATTD呈显著负相关(P< 0.05)，而NDF (r=&#8722;0.60)和ADF (r=&#8722;0.61)与干物质的IVAID有显著负相关的趋势(P< 0.10)。然而，原料的物理特性（溶胀度、系水力或黏度）与干物质、有机物的IVAID、IVATTD间并无显著相关性，原料的其他化学组分粗蛋白质、总能、酸解脂肪、木质素、可溶性纤维与干物质、有机物的IVAID、IVATTD间也并无显著相关性。此外，不可溶纤维、总纤维、不可溶性非淀粉多糖与干物质、有机物的IVAID、IVATTD的相关性要显著高于ADF和NDF，说明饲料原料中总纤维的含量比NDF和ADF更适用于估测干物质、有机物的消化率。

　　综上，一些原料总能的计算值同测定值一致，说明原料的能量贡献组分可以被分解开来，但对于DDGS和甜菜渣来说这种方法并不能包括所有含能量的养分。饲料原料的不可溶性纤维和总纤维的含量可用来估测原料干物质、有机物的IVAID、IVATTD，而无法通过原料的物理特性来估测。

　　关键词：能量，体外消化率，物理化学特性，总日粮纤维

　　Analysis for low-molecular-weight carbohydrates is needed to account for all energy-contributing nutrients in some feed ingredients, but physical characteristics do not predict in vitro digestibility of dry matter

　　D. M. D. L. Navarro, E. M. A. M.Bruininx, L. de Jong, and H. H. Stein

　　An experiment was conductedto quantify nutrient and fiber fractions of feed ingredients and to determinein vitro apparent ileal digestibility (IVAID) and in vitro apparent total tractdigestibility (IVATTD) of DM and OM in each ingredient. Ten ingredients thatvary in fiber concentration and composition were used: corn, wheat, soybeanmeal (SBM), canola meal, distillers dried grains with solubles (DDGS), corngerm meal, copra expellers, sugar beet pulp (SBP), synthetic cellulose (SF),and pectin. Correlations between chemical and physical characteristics ofingredients and IVAID and IVATTD of DM and OM were determined. The physical characteristics measured included bulk density, water-binding capacity (WBC),swelling, and viscosity. The analyzed GE was compared with values for GE calculated from all energy-contributing components. Results indicated that the analyzed chemical composition of most ingredients added to 100% or greater,except for DDGS, SBP, and SF, where nutrients added to only 94.29%, 88.90%, and96.09%, respectively. The difference between the sum of the calculated GE ofthe analyzed components and the analyzed GE of the ingredients ranged from&#8722;2.25 MJ/kg in DDGS to 1.74 MJ/kg in pectin. No correlation was observed between swelling, WBC, or viscosity and IVAID or IVATTD of DM or OM. The concentration of insoluble dietary fiber (IDF) and total dietary fiber (TDF) was negatively correlated (P < 0.05) with IVAID and IVATTD of DM and OM. There was a tendency for NDF (r = &#8722;0.60) and ADF (r = &#8722;0.61) to be negatively correlated (P < 0.10) with IVAID of DM. However, no correlation was observed between the concentration of CP, GE, acid-hydrolyzed ether extract, lignin, or soluble dietary fiber and IVAID and IVATTD of DM and OM. The stronger correlations between IDF, TDF, and insoluble non-starch polysaccharides and IVAID and IVATTDof DM and OM than between ADF and NDF and IVAID and IVATTD of DM and OM indicate that the concentration of TDF in feed ingredients is a better predictor of the digestibility of DM and OM than values for NDF and ADF. In conclusion, the calculated GE of some feed ingredients was in agreement withthe analyzed GE, which gives confidence that energy-contributing components were accounted for, but for DDGS and SBP, it was not possible to account forall analyzed GE. Concentrations of IDF and TDF, but not the physicalcharacteristics of feed ingredients, may be used to estimate IVAID and IVATTDof DM and OM in feed ingredients.

　　Key words: energy, in vitro digestibility, physicochemicalcharacteristics, total dietary fiber
　　转自： 猪营养国际论坛CSIS