Department of Animal Science, Iowa State University, Ames, IA 50011, USA.
AB Vista Feed Ingredients, Marlborough, Wiltshire SN8 4AN, United Kingdom.
J Anim Sci. 2024 Jan 3;102. doi: 10.1093/jas/skad378.
The experiment objective was to evaluate the impact of xylanase over time on viscosity and digestibility in growing pigs fed corn-based fiber. Twenty gilts with an initial body weight of 30.6 ± 0.2 kg (n = 5 per dietary treatment) were fitted with t-cannulae in the medial jejunum and terminal ileum, housed individually, and randomly assigned to one of four dietary treatments: low-fiber control (LF) with 10.4% total dietary fiber (TDF), 30% corn bran high-fiber control (HF; 26.4% TDF), HF + 100 mg xylanase/kg (XY; Econase XT 25P; AB Vista, Marlborough, UK), and HF + 50 mg arabinoxylan-oligosaccharide/kg (AX). Gilts were limit fed for three 17 d periods (P1, P2, P3); each included 5 d adaptation, 2 d fecal collection, 3 d ileal collection, 3 d jejunal collection, and 4 d related rate of passage study. Data were analyzed as repeated measures using a linear mixed model with surgery date as a random effect, and dietary treatment, period, and their interaction as fixed effects. Jejunal and ileal digesta viscosity did not differ among dietary treatments or periods (P > 0.10). There was a dietary treatment × period interaction for the apparent jejunal digestibility (AJD) of dry matter (DM), gross energy (GE), insoluble dietary fiber (IDF), neutral detergent fiber (NDF), total arabinoxylan (T-AX), total non-starch polysaccharide (T-NSP), and TDF (P≤ 0.05). In P1, LF had the greatest AJD of DM (15.5%), and relative to HF and AX, XY decreased it (9.3%, 10.1 %, and 6.3%, respectively). In P2, the AJD of DM in XY was greater than HF (11.7% vs. 9.1%) but did not differ from AX (10.5%). Relative to HF, in P3, XY increased AJD of DM (11.7 vs 15.3%), and AX decreased it (7.2%). For the AJD of NDF, AX performed intermediately in P1; in P2, relative to HF, XY, and AX increased the AJD of NDF (8.4%, 13.1%, and 11.7%, respectively), and in P3, XY, and LF did not differ (13.6 vs. 14.4%). A similar response was observed for the AJD of IDF and TDF, except for XY having the greatest AJD of IDF, T-AX, T-NSP, and TDF in P3 (P < 0.05). Compared to LF, irrespective of period, HF decreased the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of IDF, TDF, and NDF (P < 0.05). Relative to HF, XY partially mitigated this effect, improving the AID and ATTD of TDF, IDF, and NDF (P < 0.05). Increased corn-based fiber decreased nutrient digestibility, but XY partially mitigated that effect in the small intestine through enhanced fiber digestibility when given sufficient adaptation time.
实验目的是评估木聚糖酶随时间推移对生长猪玉米纤维的黏度和消化率的影响。20 头初始体重为 30.6±0.2kg 的母猪（n=5 个饲粮处理）在内侧空肠和回肠中部安装 T 型套管，单独饲养，并随机分配到 4 个饲粮处理组之一：低纤维对照组（LF），总膳食纤维（TDF）含量为 10.4%，高纤维对照组（HF），玉米麸皮 30%（TDF 含量 26.4%），HF+100mg 木聚糖酶/kg（XY；AB Vista，英国马尔伯勒）和 HF+50mg 阿拉伯木聚糖低聚糖/kg（AX）。母猪进行了三个为期 17 天的限制饲喂期（P1、P2、P3）；每个饲喂期包括 5 天适应期、2 天粪便收集期、3 天回肠收集期、3 天空肠收集期和 4 天相关通过速度研究。数据采用线性混合模型进行重复测量分析，手术日期为随机效应，饲粮处理、时期及其互作为固定效应。饲粮处理和时期对空肠和回肠食糜黏度没有影响（P＞0.10）。干物质（DM）、总表观消化率（GE）、不溶性膳食纤维（IDF）、中性洗涤纤维（NDF）、总阿拉伯木聚糖（T-AX）、总非淀粉多糖（T-NSP）和总膳食纤维（TDF）的表观空肠消化率（AJD）存在饲粮处理×时期互作（P≤0.05）。在 P1，LF 的 DM 表观消化率（15.5%）最高，与 HF 和 AX 相比，XY 降低了 DM 表观消化率（9.3%、10.1%和 6.3%）。在 P2，XY 的 DM 表观消化率高于 HF（11.7% vs. 9.1%），但与 AX 无差异（10.5%）。与 HF 相比，在 P3，XY 提高了 DM 的 AJD（11.7 vs. 15.3%），AX 降低了 DM 的 AJD（7.2%）。对于 NDF 的 AJD，AX 在 P1 中表现中等；在 P2 中，与 HF、XY 和 AX 相比，XY 和 AX 提高了 NDF 的 AJD（8.4%、13.1%和 11.7%），在 P3 中，XY 和 LF 之间没有差异（13.6 vs. 14.4%）。在 P3 中，IDF 和 TDF 的 AJD 也观察到类似的反应，除了 XY 具有最高的 IDF、T-AX、T-NSP 和 TDF AJD（P＜0.05）。与 LF 相比，HF 降低了 IDF、TDF 和 NDF 的空肠表观消化率（AID）和总肠道表观消化率（ATTD）（P＜0.05）。与 HF 相比，XY 部分缓解了这种效应，提高了 TDF、IDF 和 NDF 的 AID 和 ATTD（P＜0.05）。增加玉米纤维降低了养分消化率，但 XY 通过在给予足够适应时间时增强纤维消化率，在小肠中部分缓解了这种效应。
