【作者】 高俊勤；

【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】 本课题研究了在小麦基础日粮中添加木聚糖酶制剂对肉仔鸡肠道营养物质消化和微生物区系的影响，为进一步研究酶制剂在肉仔鸡肠道合理利用提供参考依据。论文共分为两部分：第一部分，在小麦基础日粮中添加进口酶(EⅠ)和国产酶(EⅡ)两种木聚糖酶制剂，研究了木聚糖酶对肉仔鸡各段消化道食糜停留时间和营养物质消化率的影响。试验将160只7日龄肉仔鸡分成5组：小麦基础日粮中分别添加0.05％EⅠ(A1组)、0.02％EⅠ(A2组)、0.02％EⅡ(B1组)、0.05％EⅡ(B2组)、0％(C组)，饲喂至22日龄。结果表明：在所有组中，食糜在空肠和回肠的停留时间最长。加酶使腺胃、结肠、盲肠的停留时间延长，使其它消化道停留时间缩短(P＞0.05)，A1组、A2组、B1组、B2组使总停留时间分别比对照组减少15.2％、6.4％、13.6％、13.8％。与对照组相比，加酶组可显著提高干物质和粗蛋白的总消化率。所有组中嗉囊、腺胃、十二指肠和盲肠消化率表现为负值，肌胃、空肠、回肠和结肠各段消化率为正值，且从空肠到结肠消化率有升高的趋势。第二部分，研究了小麦基础日粮中添加木聚糖酶制剂对肉仔鸡后肠微生物区系的影响。试验将120只7日龄肉仔鸡分成2组，分别添加0％、0.1％木聚糖酶，饲喂至21日龄。首先利用传统方法，研究木聚糖酶对肉仔鸡后肠道菌群数量变化、挥发性脂肪酸(VFA)和乳酸浓度的影响，试验结果表明加酶提高了盲肠乳酸菌、双歧杆菌的数量，降低了大肠杆菌的数量，但差异不显著(P＞0.05)。VFA结果表明：加酶组有增加回肠和盲肠VFA和乳酸的趋势，其中加酶组盲肠中丙酸和总挥发性脂肪酸得到显著性提高(P＜0.05)，其它则未表现出显著性差异(P＞0.05)。然后，利用PCR-DGGE技术研究了木聚糖酶对肉仔鸡后肠细菌区系变化的影响，回肠和盲肠食糜细菌16S rDNA的V6-V8可变区经PCR扩增，扩增产物经DGGE电泳后再进行相似性分析。结果表明，不管是回肠还是盲肠，加酶组的图谱比都对照组的复杂，条带相对较多，但是，组内样本间的图谱相似性不高，回肠最高为80％，盲肠最高为85％。更多还原

【Abstract】 The aim of this study was to investigate the effects of xylanse on the nutrientdigestibility and microfloar of gastrointestinal tract of broiler chickens and to provide somereferenced information for further exploration of reasonable application of enzyme inbroiler chickens production. The study included two parts and the general results werepresented as follows:In the first part: An experiment was designed to study the effects of wheat-based dietsupplemented with two xylanase preparations (foreign commercial xylanase EⅠand nativexylanase EⅡ)on the mean retention time(MRT)of digesta and the nutrient digestibility inthe segments of the gastrointestinal tract of broiler chickens. One hundred and sixty7-day-old broiler chickens were divided into five groups, namely, wheat based diets wassupplemented with 0.05% EⅠ(A1), 0.02% EⅠ(A2),0.02% EⅡ(B1),0.05% EⅡ(B2)and0%(C).The diets were fed between 7 and 22 days of age. The results showed that in allgroups, the MRT in jejunum and ileum were the longest. The MRT in proventriculus, colonand caeca were prolonged by xylanase supplementation, however, in other segments ofintestinal tract the MRT were shortened, but no significant effects were observed. Groups ofA1, A2, B1 and B2 reduced the total MRT by 15.2%, 6.4%, 13.6% and 13.8% respectively.Groups with xylanase supplemented made dry matter (DM) and crude protein(CP)digestibility increase significantly (P＜0.05). In all groups, the digestibility of DM andCP showed negative values in crop, proventriculus, duodenum and caeca and positivevalues in gizzard, jejunum, ileum and colon. There was a trend of increase from jejunum tocolon.In the second part: The study was conducted to examine the effects of wheat-baseddiet supplemented with xylanase on the microflora in the hindgut of broiler chickens. Onehundred and twenty 7-day-old broiler chickens were divided into two groups, namely,wheat-based diets was supplemented with 0% or 0.1% xylanase. The diets were fedbetween 7 and 21 days of age. Firstly, by traditional methods, examine the effect of xylanase on microbiota population, volatile fatty acid (VFA) and lactic acid concentrationin the hindgut of broiler chickens. The results showed that compared to the control group,0.1% xylanase addition group increased the counts of Lactobacillus and Bifidobacterium,reduced Escherichia coli population in caeca, but there was no significant difference(P＞0.05). Likewise, VFA and lactic acid concentration were increased by xylanasesupplementation, but no significant difference was observed exception of propionate andTVFA concentration in caeca (P＜0.05). Then, PCR and denaturing gradient geleletrophoresis (DGGE) were used to investigate the effects of wheat-based dietsupplemented with xylanase on the development of bacterial community in the hindgut ofbroiler chickens, the regions V6 to V8 of the 16S rDNA of ileum and caeca digesta bacteriawere amplified. DGGE profiles of the PCR amplification were compared by similarityanalysis. The results revealed that DGGE profiles from 0.1% xylanase addition group weremore complex than the control group, and there were more bands. However, the similarityof the DGGE profiles from the same group was not high, at most 80% in ileum and 85% incaeca.更多还原