Department of Animal Science, Iowa State University, Ames, IA.
AB Vista Feed Ingredients, Marlborough, Wiltshire, UK.
J Anim Sci. 2019 Oct 3;97(10):4293-4297. doi: 10.1093/jas/skz261.
The experimental objective was to evaluate the digestibility and fermentation differences between high and low energy corn samples and their response to xylanase supplementation. Four corn samples, 2 with higher DE content (HE-1 and HE-2; 3.74 and 3.75 Mcal DE/kg DM, respectively) and 2 with a lower DE content (LE-1 and LE-2; 3.63 and 3.56 Mcal DE/kg DM, respectively) were selected based upon a previous digestibility trial. Sixteen individually housed barrows (PIC 359 × C29; initial BW = 34.8 ± 0.23kg) were surgically fitted with an ileal T-cannula and randomly allotted to treatments in an 8 × 4 Youden square design. Dietary treatments were arranged in a 4 × 2 factorial: HE-1, HE-2, LE-1, and LE-2, with and without xylanase supplementation. Diets were formulated using one of the 4 corn samples, casein, vitamins, minerals, and 0.4% chromic oxide as an indigestible marker. Feed intake was established at approximately 3 times the estimated energy required for maintenance (NRC 2012) based upon the average initial BW of the pigs at the start of each collection period, which consisted of 9 d adaptation, 2 d of fecal, and 3 d of ileal collections. Diets, ileal, and fecal samples were analyzed for DM, GE, and total dietary fiber (TDF), to determine apparent total tract (ATTD), hindgut fermentation (HF), apparent ileal digestibility (AID) coefficients. A diet × enzyme interaction was not observed for any of the measured variables (P > 0.10). The HE-1 and HE-2 diets had greater ATTD of GE, and HE-2 diet had greater ATTD of DM (P < 0.001 and P = 0.007, respectively). Xylanase, independent of diet, improved the ATTD of GE and DM (84.8 vs. 83.6% for GE with and without enzyme, respectively, P = 0.008; and 84.2 and 83.0% with and without enzyme, respectively, P = 0.007). The energetic differences among these corn samples appeared to be driven by fermentability in the hindgut. Supplementing xylanase improves digestibility irrespective of the digestibility energy content of corn.
实验目的是评估高能和低能玉米样本之间的消化率和发酵差异及其对木聚糖酶添加的反应。根据先前的消化率试验，选择了 4 种玉米样本，其中 2 种具有较高的 DE 含量（HE-1 和 HE-2；分别为 3.74 和 3.75 Mcal DE/kg DM），2 种具有较低的 DE 含量（LE-1 和 LE-2；分别为 3.63 和 3.56 Mcal DE/kg DM）。16 头单独饲养的阉公猪（PIC 359 × C29；初始 BW = 34.8 ± 0.23kg）接受了回肠 T 型管手术，并根据 Youden 正方形设计的 8 × 4 方案随机分配到处理组中。日粮处理以 4 × 2 因子排列：HE-1、HE-2、LE-1 和 LE-2，添加和不添加木聚糖酶。日粮使用 4 种玉米样本之一、酪蛋白、维生素、矿物质和 0.4%铬氧化合物作为不可消化的标记物进行配制。根据每批收集期开始时猪的平均初始 BW，确定了饲料摄入量，大约是维持所需能量的 3 倍（NRC 2012），每批收集期包括 9 天适应期、2 天粪便收集期和 3 天回肠收集期。对饲料、回肠和粪便样品进行了 DM、GE 和总膳食纤维（TDF）分析，以确定表观全肠道（ATTD）、后肠发酵（HF）和回肠表观消化率（AID）系数。在任何测量变量中都没有观察到日粮×酶的交互作用（P > 0.10）。HE-1 和 HE-2 日粮的 GE 和 DM 的 ATTD 更高（GE 的 ATTD 分别为 0.001 和 P = 0.007，分别为 83.6%和 84.8%；DM 的 ATTD 分别为 0.007 和 P = 0.007，分别为 83.0%和 84.2%）。这些玉米样本之间的能量差异似乎是由后肠的可发酵性驱动的。添加木聚糖酶可提高 GE 和 DM 的消化率，与玉米的消化能含量无关（GE 分别添加和不添加酶的消化率分别为 84.8%和 83.6%，P = 0.008；DM 分别添加和不添加酶的消化率分别为 84.2%和 83.0%，P = 0.007）。
