【作者】 丁晓岚；

【导师】 闫素梅；

【作者基本信息】 内蒙古农业大学 ， 动物营养与饲料科学， 2005， 硕士

【摘要】 本研究针对目前抗生素等化学合成药物给人类身体健康、生态环境和我国畜牧业经济发展带来的严重负面影响,利用壳聚糖的可食用、可抗菌、可生物降解、增强免疫功能、且安全无毒、对环境无公害等特点,从寻找天然、绿色饲料添加剂出发,选用252只1日龄健康的AA雄性肉仔鸡,采用单因子随机化设计,按体重随机分成6组,每组设6个重复,每个重复7只鸡,试验日粮分别在基础日粮中添加0.00%、0.02%、0.05%、0.10%、0.30%和0.50%的壳聚糖,试验分0～3周、4～6周两阶段,共42天,从壳聚糖对肉仔鸡生长性能、营养物质的利用、血清指标、小肠绒毛发育、盲肠内容物VFA及肠道pH值等方面的影响来探讨其应用效果及作用机理,并筛选出添加效果较好的剂量。试验结果表明: 1.壳聚糖的促生长效果与壳聚糖的添加剂量有关,壳聚糖的添加量为 0.05%~0.3%时促生长效果较好,其中以添加 0.05%时促生长效果最好(P<0.05),其平均体重相对于对照组增加了 10.29%;添加量为 0.5%时未表现出促生长效果(P>0.05)。 2.在肉仔鸡日粮中添加 0.02%～0.3%的壳聚糖可显著促进体内 N 的存留,提高 N 代谢率(P<0.05),且无论前期还是后期与对照组相比均表现出较高的日表观代谢能沉积量(P<0.05),其中以添加 0.05%的壳聚糖时效果最好,添加量为 0.5%时 N的利用效果最差、日表观代谢能沉积量最低与对照组相当;壳聚糖添加剂量对能量、干物质代谢率无明显的影响(P>0.05)。 3.添加 0.5%的壳聚糖显著降低了脂肪代谢率(P<0.05)、降低了钙代谢率(P>0.05)以及血清胆固醇和甘油三酯水平(P>0.05);与对照组相比,添加壳聚糖组的血清磷水平均有所提高,但差异不显著(P>0.05),其中以 0.3%和 0.5%壳聚糖组提高的效果较好。 4.在肉仔鸡日粮中添加 0.02%～0.5%壳聚糖,可提高盲肠内容物乙酸、丁酸和总酸含量,降低肠道 pH 值,改善肠道内环境;添加 0.02%～0.3%的壳聚糖可促进小肠绒毛生长发育,使绒毛变高、变细,密度加大,而添加 0.5%的壳聚糖,小肠绒毛结构没有得到改善。 5.综合本试验结果表明:壳聚糖在肉仔鸡日粮中的适宜促生长添加量为 0.05%～0.3%,尤以 0.05%最佳。但从经济效益的角度考虑,以添加 0.05%～0.1%的壳聚糖适宜。 6.综合本研究结果初步得出,壳聚糖的促生长机理主要表现在:壳聚糖可改善肉仔鸡肠道内环境,促进小肠绒毛的生长发育,加强小肠的吸收功能,从而促进营养物质的吸收利用。较高剂量的壳聚糖添加对生长性能的不良影响可能与肉仔鸡对脂肪的吸收下降和钙磷代谢发生改变有关。更多还原

【Abstract】 Antibiotic and other chemically synthesized drugs were being used excessively, which had brought serious negative effects on human and animal health, ecology and environment protection, and on the development of Animal Husbandry in china, new green feed additives with none of these disadvantages were expected. Nowdays, Chitosan has become focus of study as a kind of excellent feed additive, with the advantages of esculent, antibacterial, hastening immunity function, security and no poisonous, innoxious to environment, none-residue in animal body etc.The experiments were carried out to study the effects of chitosan on growth performance, blood serum indices, utilization of nutriment, growth of gut villi, caecal VFA and intestine pH in broiler chickens, in order to prove the additive efficiency of chitosan and probe into the possible growth-stimulating mechanism of chitosan, moreover, to select the suitable additive dose.252 1-day-old AA male broiler chickens, with similar body weight ,were randomly allotted into six treatments with six replicates in each treatment, with seven broiler chickens in each replicate.The experiments involved six dietary levels of chitosan supplement (control: 0.00%; treat1: 0.02%; treat2: 0.05%; treat3: 0.1%; treat4: 0.3%; treat 5:0.5%).The results showed as follows: 1.The effects of chitosan on growth performance were related to the dose of chitosan added to the diet, at 0.05% level, chitosan gave the best body weight and feed gain ratio (P<0.05),compared with the control group,average body weight raised by 10.29%; but at 0.5% level, chitosan did not promote growth (P>0.05). 2.The results indicated that addition of 0.05% chitosan enhanced nitrogen retention and utilization efficiency compared with the control group (P<0.05), and also raised apparent metabolizable energy retention (P<0.05), while nitrogen utilization efficiency and apparent metabolizable energy retention of 0.5% chitosan were the worst; the metabolism rate of dry matter and apparent metabolizable energy was unaffected obviously. 3.Addition of 0.5% chitosan decreased the metabolism rate of fat in diets (P<0.05)、the metabolism rate of calcium and blood serum cholesterol , Triglyceride (P>0.05); compared with control,addition of chitosan all group raised blood serum phosphorus in different degrees. 4.Addition of 0.02%～0.5% chitosan in broiler chicken diets raised caecal acetic acid、butyric acid and total acid content, decreased caecal pH, and improved inner environment of intestine,addition of 0.02%～0.3% chitosan in diets accelerated growth of gut villi,which made gut villi become higher,thinner and density of gut villi become larger. 5.The results showed that, 0.05%～0.3% were the most suitble addition levels of chitosan in broiler chicken diets,and that 0.05% was the most suitble addition level. 6.The results suggested that growth-stimulating mechanism of chitosan were that chitosan promoted growth of gut villi and strengthened absorb function of intestine through improved inner environment of intestine,thus enhanced absorb utilization of nutriment,consequently quickened growth of broiler chickens.更多还原