理論上來說，豬玉米型基礎日糧中添加木聚糖酶可以改善營養及能量消化率、纖維發酵特性，但是改善的效果卻不穩定。本試驗的目的在于研究在豬日糧中含有高不可溶纖維（20%中性洗滌纖維）時，木聚糖酶對能量、養分消化率、食糜粘度、發酵特性的影響。試驗日糧適應期為46天。將3組生長期的小母豬（每組20頭）根據體重隨機分至4個日糧處理，每頭母豬單獨飼養。試驗處理包括：低纖維對照組（7.5%中性洗滌纖維）、高纖維對照組（30%玉米皮，21.9%中性洗滌纖維）、高纖維木聚糖酶組（高纖維對照組+100 mg/kg木聚糖酶）、木寡糖組（高纖維對照組+50 mg/kg阿拉伯木寡糖，3-7個木糖聚合）。小母豬自由采食處理日糧36天。第36天時，將豬飼喂于代謝籠中，持續10天，定量采食，收集糞便。第46天，屠宰試驗豬，收集回腸、盲腸和結腸食糜。試驗數據經線性混合模型進行統計分析，試驗處理為固定效應，試驗區組和重復為隨機效應。
與低纖維組相比，高纖維處理降低了干物質、總能、粗蛋白、酸性洗滌纖維、中性洗滌纖維和半纖維素的回腸表觀消化率、盲腸表觀消化率、結腸表觀消化率和全腸道表觀消化率（P＜0.01）。與高纖維組相比，木聚糖酶的添加顯著提高了總能、粗蛋白和中性洗滌纖維的回腸表觀消化率（P＜0.05），并改善了干物質、總能、粗蛋白、中性洗滌纖維、酸性洗滌纖維和半纖維素盲腸表觀消化率、結腸表觀消化率和全腸道表觀消化率（P < 0.05）。所有處理組中，高纖維日糧組后腸道干物質損失顯著提高（P=0.031）。木聚糖酶的添加提高了干物質（162 VS 98g；P=0.008）和中性洗滌纖維（44 VS 13g，P＜0.01）在盲腸的消失量。木聚糖酶的添加提高了盲腸食糜中乙酸的比例和結腸食糜中丁酸的比例（P＜0.05）。與低纖維組相比，高纖維組回腸、盲腸和結腸食糜粘度顯著提高，但是添加木聚糖酶后回腸食糜粘度顯著下降（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.