【作者】 郝钢；

【导师】 许丽；

【作者基本信息】 东北农业大学 ， 动物营养与饲料科学， 2005， 硕士

【摘要】 壳聚糖是目前自然界唯一含阳离子的可食性动物纤维,也是继蛋白质、糖、脂肪、维生素、矿物质以外的第六生命要素,具有抗菌、抗病毒作用,还有调节脂肪代谢、增强免疫力等一系列功效,被认为是一种新型的饲料添加剂。本研究通过饲养试验、代谢试验和屠宰试验比较了不同浓度壳聚糖对肉仔鸡的生长性能、营养物质利用率和免疫功能的影响,并通过体外抑菌试验比较了不同浓度和不同脱乙酰度壳聚糖对鸡常见病原菌的抑制作用。 将120只1日龄健康爱拔益加(AA)肉仔鸡随机分成5组,每组3个重复,每重复8只鸡。对照组(Ⅰ)饲喂基础日粮(不添加任何药物),试验组(Ⅱ、Ⅲ、Ⅳ、Ⅴ)分别在基础日粮中添加10g/kg、20g/kg、30g/kg壳聚糖和5mg/kg黄霉素,试验期7周。每周以重复为单位称量各组试鸡的体重和采食量,计算平均日增重、日采食量和饲料转化率。试验结果表明:从生长全期看,1～49日龄各组平均日增重分别为48.73g、45.86g、44.01g、45.60g、48.85g,添加壳聚糖的各组与对照组相比,降低了日增重(p<0.05)和日采食量(p>0.05),而壳聚糖各组间无显著差异(p>0.05);与黄霉素组比较,壳聚糖各组均不能与其抗衡。从各生长阶段看,1～21日龄各组日增重分别为29.26g、28.83g、26.07g、25.75g、29.65g,壳聚糖10g/kg组日增重和日采食量于对照组相比无显著差异,Ⅲ、Ⅳ组日增重和日采食量显著降低(p<0.05),22～49日龄各组日增重分别为63.34g、58.64g、57.47g、60.48g、63.26g,添加壳聚糖的Ⅱ、Ⅲ组日增重均显著低于对照组和黄霉素组(p<0.05)。 在饲养试验期间,将所有试验鸡进行为期4天的代谢试验。试验结果表明,与对照组和黄霉素组相比,添加壳聚糖不同程度地降低了能量、蛋白质、钙和磷的表观利用率,壳聚糖各组间差异不显著(p>0.05)。 在21、35和49日龄,各重复取1只鸡,测定T淋巴细胞比率,外周血淋巴细胞转化率,HI抗体效价,血清IgA,IgG,IgM水平和胸腺、法氏囊、脾脏免疫器官指数。试验结果表明,在日粮中添加壳聚糖,对试验全期肉仔鸡的法氏囊指数,胸腺指数和脾脏指数无显著影响;壳聚糖能够提高T淋巴细胞比率,且随壳聚糖添加量的增大,T淋巴细胞比率也增大;壳聚糖能够提高肉仔鸡HI抗体水平;1～21日龄血清免疫球蛋白水平随壳聚糖添加量的增加而增加,22～49日龄各组间无显著影响。 采用琼脂扩散纸片法进行体外抑菌,观察不同浓度和不同脱乙酰度壳聚糖对鸡常见病原菌生长的影响。结果表明,壳聚糖对四种鸡常见病原菌(鸡大肠杆菌、鸡白痢沙门氏杆菌、金黄色葡萄球菌、禽多杀性巴氏杆菌)均具有抑制作用。同一脱乙酰度壳聚糖的抑菌效果,随着壳聚糖浓度的增大而增强,在2%至2.5%时抑菌效果达到最佳。脱乙酰度高的壳聚糖抑菌效果好于脱乙酰度低的壳聚糖。对菌种来说,壳聚糖对禽多杀性巴氏杆菌的抑菌效果最好。更多还原

【Abstract】 Chitosan is the only edible animal fiber with cation in the nature, and is the sixth basal nutrition (protein, sugar, fat, vitamin and minerals) .It is called a type of new additives which has the effectiveness of antibiotic activity, antivirus activity, adjusting metabolism of fat and improving immunity and so on. The experiment was conducted to study the effect of the different concentration of chitosan on performance, availability of nutrition and immunological function by feeding trial, metabolic trial and slaughter trial. And the antibacterial effect of chitosan with different concentration and different deacelylated degree against chicken pathogenic bacteria in vitro was studied.120 Arbor Acre broilers (1d of age) were randomly divided into five groups, with three replications per group, and per replication was eight broilers. The control group ( Group Ⅰ) was fed with corn-soybean meal basal diet, the trial groups ( Group Ⅱ, Ⅲ, Ⅳ and Ⅴ ) with basal diet plus 10g/kg, 20g/kg, 30g/kg chitosan, and 5mg/kg Flavomycin, respectively. The raising period is seven weeks. Weights, gains and feed intakes of every replication were weight every weekend, and average daily gains, feed intakes and feed efficiency were calculated. The result showed that from 1 to 49 day, daily gains of all groups were 48.73g, 45.86g, 44.01g, 45.60g, 48.85g, respectively. Chitosan supplement decreased daily gains ( p < 0.05 ) and feed intakes ( p > 0.05 ) during the whole growing stage, and there was no difference between chitosan groups ( p > 0.05 ) . Daily gains and feed intakes of Flavomycin group were higher than these of chitosan groups and the control group. During every raising stage, from 1 to 21 day, daily gains of groups were 29.26g, 28.83g, 26.07g, 25.75g, 29.65g respectively. Daily gains and feed intakes of chitosan 10g/kg group had no difference with the control group, these of Ⅲ,Ⅳ groups decreased significantly ( p < 0.05 ) . From 22 to 49 day, daily gains of groups were 63.34g, 58.64g, 57.47g, 60.48g, 63.26g ,respectively. Daily gains of Ⅱ, Ⅲ group were lower than the control and Flavomycin groups significantly ( p <0.05) .Metabolic trial began from 17d to 21d. The result showed that in contrast with the control and Flavomycin groups, chitosan supplement decreased differently availability of energy , protein , calcium and phosphorus , but there was no difference between chitosan groups ( p > 0.05 ) .At 2 Id, 35d and 49d, blood samples were obtained from one broiler of each group to measure T lymphocytes percentage, T lymphocytes blastogenic response to ConA in blood, HI titers, IgA, IgG, IgM in serum and indexes of immune organs of Thymus gland, Bursa of Fabricius and spleen. The result showed that chitosan supplement had no difference on indexes of thymus gland, Bursa of Fabricius and spleen. Chitosan supplement improved T lymphocytes percentage, and it had an increased current with the increase of supplement. In the whole growing stage, chitosan supplement improved HI titers; serum Ig had an increased current with the increase of chitosan supplement at 21d,but there were no difference at 49d.The influence of chitosan with different concentration and different deacelylated degree were observed on the growth of chicken pathogenic bacteria cultured in vitro with Agar Pervasion Paper Method The experimental results demonstrated that four chicken pathogenic bacteria (Escherichia coli, Salmonella pullorum, Staphylococcus aureus, Pasteurella multocida) could be inhibited to different degrees by chitosan. The antibiotic activity of chitosan with the same deacelylated degree was enhanced with the increase of concentration of chitosan, and showed the best in the concentration from 2% to 2.5%. The antibiotic activities of three descelylated degree chitosan was enhanced with the increase of descelylated degree.Chitosan inhibited the growth of Pasteurella multocida more effectively than other three pathogenic bacteria.更多还原