理论上来说，猪玉米型基础日粮中添加木聚糖酶可以改善营养及能量消化率、纤维发酵特性，但是改善的效果却不稳定。本试验的目的在于研究在猪日粮中含有高不可溶纤维（20%中性洗涤纤维）时，木聚糖酶对能量、养分消化率、食糜粘度、发酵特性的影响。试验日粮适应期为46天。将3组生长期的小母猪（每组20头）根据体重随机分至4个日粮处理，每头母猪单独饲养。试验处理包括：低纤维对照组（7.5%中性洗涤纤维）、高纤维对照组（30%玉米皮，21.9%中性洗涤纤维）、高纤维木聚糖酶组（高纤维对照组+100 mg/kg木聚糖酶）、木寡糖组（高纤维对照组+50 mg/kg阿拉伯木寡糖，3-7个木糖聚合）。小母猪自由采食处理日粮36天。第36天时，将猪饲喂于代谢笼中，持续10天，定量采食，收集粪便。第46天，屠宰试验猪，收集回肠、盲肠和结肠食糜。试验数据经线性混合模型进行统计分析，试验处理为固定效应，试验区组和重复为随机效应。
与低纤维组相比，高纤维处理降低了干物质、总能、粗蛋白、酸性洗涤纤维、中性洗涤纤维和半纤维素的回肠表观消化率、盲肠表观消化率、结肠表观消化率和全肠道表观消化率（P＜0.01）。与高纤维组相比，木聚糖酶的添加显著提高了总能、粗蛋白和中性洗涤纤维的回肠表观消化率（P＜0.05），并改善了干物质、总能、粗蛋白、中性洗涤纤维、酸性洗涤纤维和半纤维素盲肠表观消化率、结肠表观消化率和全肠道表观消化率（P < 0.05）。所有处理组中，高纤维日粮组后肠道干物质损失显著提高（P=0.031）。木聚糖酶的添加提高了干物质（162 VS 98g；P=0.008）和中性洗涤纤维（44 VS 13g，P＜0.01）在盲肠的消失量。木聚糖酶的添加提高了盲肠食糜中乙酸的比例和结肠食糜中丁酸的比例（P＜0.05）。与低纤维组相比，高纤维组回肠、盲肠和结肠食糜粘度显著提高，但是添加木聚糖酶后回肠食糜粘度显著下降（P＜0.001）。
The influence of xylanase on the fermentability, digestibility, and physicochemical properties of insoluble corn-based fiber along the gastrointestinal tract of growing pigs
In theory, supplementing xylanase in corn-based swine diets should improve nutrient and energy digestibility and fiber fermentability, but its efficacy is inconsistent. The experimental objective was to investigate the impact of xylanase on energy and nutrient digestibility, digesta viscosity, and fermentation when pigs are fed a diet high in insoluble fiber (>20% neutral detergent fiber; NDF) and given a 46-d dietary adaptation period. A total of 3 replicates of 20 growing gilts were blocked by initial body weight, individually housed, and assigned to 1 of 4 dietary treatments: a low-fiber control (LF) with 7.5% NDF, a 30% corn bran high-fiber control (HF; 21.9% NDF), HF + 100 mg xylanase/kg (HF + XY [Econase XT 25P; AB Vista, Marlborough, UK]) providing 16,000 birch xylan units/kg; and HF + 50 mg arabinoxylan-oligosaccharide (AXOS) product/kg (HF + AX [XOS 35A; Shandong Longlive Biotechnology, Shandong, China]) providing AXOS with 3–7 degrees of polymerization. Gilts were allowed ad libitum access to fed for 36-d. On d 36, pigs were housed in metabolism crates for a 10-d period, limit fed, and feces were collected. On d 46, pigs were euthanized and ileal, cecal, and colonic digesta were collected. Data were analyzed as a linear mixed model with block and replication as random effects, and treatment as a fixed effect. Compared with LF, HF reduced the apparent ileal digestibility (AID), apparent cecal digestibility (ACED), apparent colonic digestibility (ACOD), and apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE), crude protein (CP), acid detergent fiber (ADF), NDF, and hemicellulose (P < 0.01). Relative to HF, HF + XY improved the AID of GE, CP, and NDF (P < 0.05), and improved the ACED, ACOD, and ATTD of DM, GE, CP, NDF, ADF, and hemicellulose (P < 0.05). Among treatments, pigs fed HF had increased hindgut DM disappearance (P = 0.031). Relative to HF, HF + XY improved cecal disappearance of DM (162 vs. 98 g; P = 0.008) and NDF (44 vs. 13 g; P < 0.01). Pigs fed xylanase had a greater proportion of acetate in cecal digesta and butyrate in colonic digesta among treatments (P < 0.05). Compared with LF, HF increased ileal, cecal, and colonic viscosity, but HF + XY decreased ileal viscosity compared with HF (P < 0.001). In conclusion, increased insoluble corn-based fiber decreases digestibility, reduces cecal fermentation, and increases digesta viscosity, but supplementing xylanase partially mitigated that effect.