【作者】 刘记强；

【导师】 康相涛；

【作者基本信息】 河南农业大学 ， 饲料作物生产与利用， 2009， 博士

【摘要】 本论文研究探讨了固始鸡对日粮中粗纤维的耐受水平及其耐粗饲机理,对充分利用自然资源,解决“人畜争粮”矛盾,保持家禽生产企业的市场竞争优势,满足广大消费者对“三高一低”优质、绿色、健康禽产品的需求和固始鸡的品种保护与开发利用具有重要意义。研究分为两个部分,第一部分研究了全收粪法和指示剂法在测定固始鸡粗纤维消化率中的差异性,探讨了采用指示剂法替代全收粪法测定固始鸡高纤维日粮中相关养分消化率的可行性;第二部分研究了日粮不同纤维水平对0～8周龄固始鸡体重、体尺、内脏器官发育、免疫器官发育、肠道形态结构、血清生化指标、盲肠纤维素酶活性的影响,并采用PCR-DGGE技术研究了日粮纤维水平对盲肠微生物定植规律的影响。具体试验结果如下:第一部分:随机挑选26只体重相近、健康无病的24周龄纯系固始公鸡,在其饲粮中添加9%的松针粉（日粮粗纤维含量经实际测定为4.7%）,先后分别采用全收粪法、外源指示剂（TiO₂）法、内源指示剂（4N-AIA）法测定其粗纤维消化率,并比较其差异性。结果表明:3种方法在测定粗纤维消化率时有差异,内源指示剂（4N-AIA）法的测定值高于全收粪法,全收粪法的测定值高于外源指示剂（TiO₂）法,但3种方法的测定值之间差异均不显著（P＞0.05）。采用全收粪法测得TiO₂回收率平均为97.2%;AIA回收率平均为102.7%。相关性分析表明,采用全收粪法、外源指示剂（TiO₂）法和内源指示剂（4N-AIA）法所测得鸡的粗纤维消化率呈极显著相关（P＜0.01）,相关系数分别为0.968、0.971和0.971。在测定鸡日粮中养分消化率时可以采用指示剂法代替全收粪法。第二部分:选取同批孵化的健康固始鸡慢羽纯系雏鸡1 152只,随机分为6组,每组设4个重复,每个重复48只,公母各半,分别饲喂含粗纤维2.51%（对照组）、3.4796（试验Ⅰ组）、4.58%（试验Ⅱ组）、5.57%（试验Ⅲ组）、6.68%（试验Ⅳ组）、7.79%（试验Ⅴ组）的日粮,饲养期8周。研究了日粮不同纤维水平对0～8周龄固始鸡体重、体尺、内脏器官发育、免疫器官发育、肠道形态结构、血清生化指标、盲肠纤维素酶活性的影响,并采用PCR-DGGE技术研究了日粮纤维水平对盲肠微生物定植规律的影响。结果表明:（1）在2、4、6、8周龄时试验各组与对照组固始鸡体重没有显著差异（P＞0.05）。（2）在2、4、6、8周龄时。试验组与对照组的胫长差异不显著（P＞0.05）;在6周龄和8周龄时,试验组与对照组间胫围、胸宽、胸深、体斜长、龙骨长、骨盆宽、胸角差异不显著（P＞0.05）。（3）在2、4、6、8周龄时固始鸡各肠段长度、大多数内脏器官重和器官指数试验组与对照组差异不显著（P＞0.05）,仅部分内脏器官和器官指数存在组间差异。肌胃、肝脏、胰脏试验组与对照组相比出现一定程度的代偿性生长,但器官重组间差异不显著（P＞0.05）;日粮纤维水平对固始鸡肠道各段长度的影响差异不显著,与对照组相比,试验组没有出现代偿性生长。（4）在4周龄和8周龄时,试验组的十二指肠、空肠、回肠的绒毛高度均随日粮中粗纤维含量增加而增加,隐窝深度随日粮粗纤维含量增加而降低,盲肠的绒毛高度随日粮纤维含量增加而增加。在2、4、6、8周龄时对试验组各肠段的电镜扫描可见,肠道表面绒毛捧列整齐,粗纤维水平对固始鸡小肠绒毛的表观形态的影响差异不明显,且试验日粮的粗纤维水平对小肠绒毛没有造成明显的损伤。（5）在同一周龄时,除6周龄时试验Ⅳ组的盲肠纤维素酶活性低于试验Ⅲ组外,固始鸡的盲肠纤维素酶活性随日粮粗纤维水平的提高而显著提高或呈提高趋势,而且随着周龄的增大,对照组和试验各组固始鸡的盲肠纤维素酶活性均提高显著。（6）4周龄时随着日粮粗纤维水平提高,谷草转氨酶活性和血糖浓度除试验Ⅱ组与对照组差异显著外,其他各组与对照组均差异不显著（P＞0.05）;低密度脂蛋白含量试验组均比对照组高且差异显著（P＜0.05）;血清总蛋白含量、白蛋白含量、碱性磷酸酶的活性、甘油三酯含量、总胆固醇含量、高密度脂蛋白含量试验组与对照组差异均不显著（P＞0.05）。8周龄时随日粮粗纤维水平提高,除谷草转氨酶活性试验Ⅲ组与对照组差异显著外,总蛋白含量、白蛋白含量、尿素氮含量、碱性磷酸酶活性、血糖浓度、总胆固醇、甘油三酯、高密度脂蛋白、低密度脂蛋白含量试验组与对照组差异均不显著（P＞0.05）。（7）除在4周龄时胸腺指数试验Ⅱ组与对照组差异显著、在6周龄时法氏囊指数试验Ⅱ组与对照组差异显著、在8周龄时脾脏指数试验Ⅱ组与对照组差异显著（P＜0.05）外,其余各周龄时试验组与对照组免疫器官指数差异均不显著（P＞0.05）。（8）在2、4、6、8周龄时,随着日粮纤维水平提高,固始鸡盲肠微生物16S rDNA的V₃区PCR扩增产物的DGGE图谱条带数增加,同一周龄时随日粮纤维水平的增加,微生物的种类和数量显著增加或呈增加趋势,日粮纤维促进了与纤维分解相关的细菌的增殖;同组固始鸡随着日龄的增加,微生物的种类和数量有所增加但无显著差异,在2周龄时盲肠已建立结构复杂且相对稳定的微生物种群。本研究提示,固始鸡具有较强的抗逆性,对日粮中粗纤维具有较强的耐受能力,在消化吸收器官没有出现明显的代偿性生长的情况下,即可从高纤维日粮中获取所需营养物质,维持血液中营养物质浓度没有出现显著变化,而且对体重和体型发育没有产生显著影响。可能是固始鸡适应长期的粗饲条件,消化吸收系统发生适应性变异,可以充分消化吸收高纤维饲粮中的营养物质,以满足自身的营养需要。可以在其日粮中添加较高水平的粗纤维以降低生产成本。固始鸡对粗纤维的耐受阈值有待于进一步研究。更多还原

【Abstract】 This paper studied the crude fiber level Gushi chicken could tolerate in diet and probed into the mechanism of Gushi chicken high level crude fiber tolerance capacity, this research would be of great significance to make full use of natural resources, resolve the demand conflict on the grain between human and livestocks, keep the competition advantages in market for the poultry industry, meet the consumers’ need for healthful and good quality poultry product, and the breed protect and exploitation of Gushi chicken. It includes two parts, in experiment I the differences between total fecal collection method and indicator method in the digestibility determination of crude fiber were studied in Gushi chicken, and the replacement feasibility of total fecal collection method with indicator method in the nutrient digestibility determination for high level crude fiber diet in Gushi chicken was discussed. Effect of dietary crude fiber levels on body weight, body measurements, development of internal organs and immune organs, intestinal morphology and structure, serum biochemical parameters, caecum cellulase activity, and caecum microflora colonization law by PCR-DGGE were researched in Gushi chicken aged from 0 to 8 weeks in experiment II. The experimental results were as follows:Part I : Twenty six 24-wk-old healthy Gushi cocks with almost same body weight were selected and were fed on the diet supplemented with 9% pine leaf powder （crude fiber content was measured as 4.7%）, crude fiber digestibility of which were determined by total fecal collection method, exogenous indicator （TiO₂） method and endogenous indicator （4N-AIA, acid insoluble ash） method respectively, and the differences among three methods were compared. The results indicated that there were difference between either of the two methods,but there were no significant difference between either of the two methods （P>0.05）. Fecal recovery of TiO₂ averaged 97.2%, whereas that of 4N-AIA averaged 102.7% based on total fecal collections. Correlation analysis indicated that there were significant correlation between the crude fiber digestibility determined by total fecal collection method, exogenous indicator and endogenous indicator methods （P < 0.01） , the coefficient were 0.968, 0.971 and 0.971 respectively. Total fecal collection method could be replaced by indicator method in the determination of crude fiber digestibility for Gushi chicken.Part II: One thousand one hundred and fifty two 1-day-old Gushi chickens were selected and were randomly assigned to 6 groups, which consists of 4 replicates with half male and half female chickens. Six groups were fed to 8 weeks of age with crude fiber content 2.51% （control group）、3.47% （group I ）、4.58% （group II ）、5.57%（group III）、6.68% （group IV ）、7.79% （group V） in diets respectively. Effect of dietary crude fiber levels on body weight, body measurements, development of internal organs and immune organs, intestinal morphology and structure, serum biochemical parameters, caecum cellulase activity, and caecum microflora colonization law by PCR-DGGE were researched in Gushi chicken aged from 0 to 8 weeks. Results indicated that （1） There were no significant differences on Gushi chicken body weight between control group and experimental groups at 2, 4, 6, 8 weeks of age （P > 0.05） . （2） There were no significant differences on Gushi chicken shank length between control group and experimental groups at 2, 4, 6, 8 weeks of age （P > 0.05） ; there were no significant differences on Gushi chicken shank girth, breast width, breast depth, body length, keel length, pelvis width, breast angle between control group and experimental groups at 6, 8 weeks of age （P > 0.05） . （3） There were no significant differences on the development of Gushi chicken duodenum, jejunum, ileum, cecum and most internal organs between control group and experimental groups at 2,4, 6, 8 weeks of age （P > 0.05）. There were hyperplasia on Gushi chicken gizzard, proventriculus, liver and pancreas in experimental group compared to control group, but there were no significant difference on their weight （P> 0.05） ;there were no significant effect of crude fiber level on intestinal length, and there were no hyperplasia on Gushi chicken intestine in experimental group compared to control group. （4） With the increase of dietary crude fiber level, villus height of Gushi chicken duodenum, jejunum, ileum, cecum increased, while crypt depth decreased at 4 and 8 weeks of age. Crude fiber promoted the growth of intestinal villus. The intestinal villus were located in order observed under scanning electron microscopes, crude fiber level had no significant effect on the intestinal morphology in Gushi chicken. （ 5 ） The cecum cellulase activity of Gushi chicken were significantly increased with the dietary crude fiber level increased at 2, 4, 6, 8 weeks of age, except that the cecum cellulase activity of experimental group IV was lower than that of experimental group III at 6 weeks of age. And with the increase of weeks of age, the cecum cellulase activity of experimental group and control group were increased. （6） Dietary crude fiber level had no significant difference on activity of serum glutamate-oxalacetate transaminase and glucose concentration between experimental group and control group except experimental group II, there were significant difference on serum low density lipoprotein between experimental group and control group experimental groups （P< 0.05） ;while there were no significant difference on serum total protein, albumin, urea nitrogen, alkaline Phosphatase, triglyceride, cholesterol, high density lipoprotein between experimental group and control group experimental groups at 4 weeks of age in Gushi chicken （P > 0.05）. At 8 weeks of age, there were no significant difference on activity of serum glutamate-oxalacetate transaminase between experimental groups and control group except experimental group III, and there were no significant difference on serum total protein, albumin, urea nitrogen, glucose concentration, alkaline Phosphatase, triglyceride, cholesterol, high density lipoprotein between experimental groups and control group （P > 0.05）. （7） There were no significant difference on the development of spleen, thymus, bursal of Gushi chicken between experimental groups and control group at 2, 4, 6, 8 weeks of age （P > 0.05）, except that there were significant difference on the development of thymus at 4 weeks of age, the development of bursal at 6 weeks of age and the development of spleen at 8 weeks of age between experimental group II and control group （P < 0.05）. （8） With the increase of dietary crude fiber level, the band numbers of DGGE profiles of the V₃ region gene amplication of 16S rDNA of caecum microflora increased, it meant the significant increase or increase tendency of cecum microflora quantity and diversity at 2, 4, 6, 8 weeks of age, and the dietary crude fiber promoted the reduplication of bacterial connected with crude fiber decomposition, while there were no significant difference between 8 weeks of age and 2, 4, 6 weeks of age in the same group, although increased with increasing in their ages. The complex and stable microflora in cecum had been established in Gushi chicken at 2 weeks of age.The results of this research indicated that Gushi chicken could tolerate high level crude fiber in diet and obtain the necessary nutrient from it, to maintain certain level nutrition in, and there were no significant effect on their body weight and body development without significant hyperplasia in digestive organs. Probably Gushi chicken acclimatized themselves to high level crude fiber in diets for a long time that adjustable variances had taken place in digestive system, that it could fully digest and absorb the nutrient from low quality diets to meet their requirements. It meant that high level crude fiber could be added into the Gushi chicken diets to decrease the product cost, the threshold of crude fiber Gushi chicken could tolerate in diet would be detected in further study.更多还原