【作者】 徐骏；

【导师】 高峰；

【作者基本信息】 南京农业大学 ， 动物营养与饲料科学， 2007， 硕士

【摘要】 为提高小麦饲料营养价值，本文通过体外法和体内法在小麦基础日粮中添加木聚糖酶制剂对肉仔鸡生长性能、养分的消化率和主要产物的生成量以及代谢的影响，对木聚糖酶制剂作用机理进行了探讨。1、体外模拟法研究木聚糖酶对小麦日粮中养分消化率、产物生成量以及相对黏度的影响。结果表明不同水平的木聚糖酶可显著提高粗蛋白和半纤维素的消化率（P＜0.05）。添加木聚糖酶2560FXU／kg可提高蛋白消化率5.12个百分点。和对照组相比，添加不同水平的木聚糖酶可显著地降低酶解液的相对粘度（P＜0.01）。随着木聚糖酶添加量的增加，酶解液的相对黏度逐渐下降。随着酶作用时间的延长，相对粘度先是上升，而后下降。小麦日粮添加不同水平的木聚糖酶后，可显著提高上清液中阿拉伯糖、葡萄糖和阿拉伯低聚木糖的浓度（P＜0.05）。同时也显著降低了阿拉伯低聚木糖中阿拉伯糖与木糖的比值（A／X）。2、小麦日粮中添加木聚糖酶对肉仔鸡生长性能、消化和代谢的影响。结果表明肉仔鸡日粮中添力0.03％和0.1％的木聚糖酶使21日龄肉仔鸡增重提高了3.08％-5.92％，料重比降低了2.5％-5％。其中添加0.1％木聚糖酶显著提高了增重（P＜0.05），同时显著降低了料重比（P＜0.05）。相对于小麦对照组，添加0.1％的木聚糖酶使消化器官相对重量和肠道长度表现不同程度的下降，但差异不显著（P＞0.05）。木聚糖酶使消化道食糜pH值有升高的趋势，但差异不显著（P＞0.05）。木聚糖酶显著提高了回肠脂肪表观消化率和总肠道蛋白表观消化率（P＜0.05），极显著提高了回肠和总肠道半纤维素消化率（P＜0.01）。木聚糖酶可显著提高嗉囊、肌胃、十二指肠、空肠、回肠食糜中阿拉伯糖的含量（P＜0.05），显著提高了嗉囊、十二指肠和回肠食糜中木糖含量（P＜0.05），同时也显著提高了回肠食糜中葡萄糖的含量（P＜0.05）。木聚糖酶显著提高了十二指肠、空肠、回肠和盲肠食糜中阿拉伯低聚木糖的含量（P＜0.05）。对功能性寡糖：异麦芽糖、潘糖、异麦芽三糖和蔗果三糖含量没有明显影响（P＞0.05）。木聚糖酶分别使血液中总蛋白、白蛋白、尿酸和葡萄糖的含量提高了26.6％、44.5％（P＜0.05）、7.6％和25.1％（P＜0.01）。木聚糖酶使血液中的胆固醇和甘油三酯含量比对照组降低了19.1％（P＜0.05）和16.9％。木聚糖酶使血液中胰高血糖素和T₃含量比对照组降低了18.06％和5.53％，使胰岛素和T₄含量分别提高了6.96％、29.07％，但差异均不显著（P＞0.05）。更多还原

【Abstract】 In order to improve the nutritional value of the wheat, this study was conducted to investigate the effects of xylanase supplemented to wheat-based diets on performance, nutrient digestibility, oligosaccharide generation and metabolism in vivo and in vitro. The objective of this study was to explore the action mechanism of xylanase.1. The effects of xylanase on nutrient digestibility, oligosaccharides generation and relative viscosity in wheat-based diet in vitro.The results showed that the digestibility of crude protein and hemicelluloses in wheat-based diet was significantly improved (P<0.05). When adding 2560FXU/kg xylanase to wheat-based, the digestibility of crude protein could increase by 5.12 percentage point. The relative viscosity of xylanase-extracted solution from wheat-based diet was significantly reduced due to xylanase addition (P<0.01). However, the relative viscosity of xylanase-extracted solution was in a quadratic response to the prolongation of xylanase-hydrolyzation time. The concentrations of arabinose, glucose and arabinoxylooligosaccharide in xylanase-extracted solution from wheat-based diet were significantly enhanced (P<0.05). The value of arabinose/xylose in arabinoxylooligosaccharide was significantly decreased.2. The effects of xylanase on broiler chickens performance, digestion and metabolism.The results showed that 0.3% and 0.1% xylanase supplementation increased body weight gain by 3.08%-5.92% and decreased feed to weight gain ratio 2.5%-5%. The 0.1% xylanase supplementation significantly improved body weight gain and feed conversion efficiency (P<0.05). The relative weight of digestive organs and the length of the intestine were decreased with enzyme supplementation (P>0.05) . The pH value of chyme was increased with enzyme supplementation (P>0.05 ) . The ileal apparent digestibility of crude fat and fecal apparent digestibility of protein was significantly improved (P<0.05) with enzyme supplementation. The ileal and fecal digestibility of hemicelluloses was very significantly increased (P<0.01). The supplementation of xylanase significantly improved the concentration of arabinose in crop, proventriculus, duodenum, jejunum and ileum (P<0.05 ), the concentration of xylose in crop, duodenum, ileum (P<0.05 ) and the concentration of glucose in ileum(P<0.05). The supplementation of xylanase also significantly improved the concentration of arabinoxylooligosaccharide in duodenum, jejunum, ileum and caeca (P<0.05). However, the supplementation of xylanase had no effect on the concentration of isomaltose, panose, isomaltriose and kestose (GF2) (P>0.05).The supplementation of xylanase respectively increased the level of total protein, albumin, uric acid and glucose of blood serum by 26.6%, 44.5% (P<0.05), 7.6% and 25.1% (P<0.01). The supplementation of xylanase respectively decreased the concentration of cholesterol and triglyceride of blood serum by 19.1% ( P<0.05 ) and 16.9%. The supplementation of xylanase respectively decreased the level of glucagon and T3 by 18.06% and 5.53% and respectively improved the level of insulin and T4 by 6.96% and 29.07%, but all were not significant (P>0.05).更多还原