【作者】 李娜；

【导师】 杨德吉；

【作者基本信息】 南京农业大学 ， 临床兽医学， 2016， 硕士

【摘要】 鸡白痢是危害畜禽养殖业的重要传染病之一,其主要的预防治疗措施是抗生素的应用。但是,抗生素的使用不当导致细菌的耐药性。因此迫切需要寻找一种能够辅助甚至取代抗生素,用于预防和治疗鸡白痢的药物。铜离子具有良好的抗菌性能,能够抑制许多病原菌的生长,同时对有害真菌的抑制作用也非常突出。凹凸棒石具有良好的吸附性能,由于其独特的晶体结构使它具有较大的比表面积,能够吸附细菌和毒素。本试验将二者的优点结合起来,制备载铜凹凸棒石无机抗菌剂,并对载铜凹凸棒石的抗菌机理作初步探索以及对鸡白痢预防和治疗效果的研究,以期为鸡白痢的药物研制提供理论依据。本实验首先对载铜凹凸棒石的制备条件进行优化,探索不同处理温度的凹凸棒石以及反应温度对载铜量的影响,以及不同的载铜凹凸棒石对小鼠腹泻的治疗效果的研究。结果表明,反应温度对载铜量影响比较大。在反应温度为90 ℃时,载铜量最高,为51.05 mg/g。处理温度为350 ℃和105 ℃,载铜量没有显著变化。在小鼠腹泻治疗试验中,同一使用量,载铜量越高,对小鼠的治疗效果越好。350 ℃和105 ℃处理温度的载铜凹凸棒石对小鼠的治疗效果相似,考虑到大量生产,因此可以将凹凸棒石处理温度改为105 ℃。其次,载铜凹凸棒石的抗菌性能以及抗菌机理进行初步研究。杀菌性能的测定:不同质量的载铜凹凸棒石杀菌效果不同,随着质量浓度增大而增大,凹凸棒石只表现吸附细菌的能力;载铜凹凸棒石的铜离子在LB和生理盐水中的释放量不随时间变化。细菌胞内酶活性结果显示,载铜凹凸棒石作用于细菌,细菌死亡,导致胞内酶大量外漏,结果表明,载铜凹凸棒石具有强大的杀菌作用,而载铜凹凸棒石的抗菌能力是两方面的协同作用:一方面是载铜凹凸棒石能吸附细菌;另一方面是它释放的铜离子对细菌的抑制和杀灭作用。然后,用载铜凹凸棒石对鸡白痢的预防和治疗效果进行研究。在预防效果试验中,预防1组(每公斤饲料添加1%载铜凹凸棒石)死亡率最低,肝脏、盲肠带菌数量明显减少,并且预防1组的盲肠细菌数目显著比感染组低。与感染组相比,前期平均终重、平均日增重虽无明显差异,但是料肉比明显降低。后期平均日增重明显比感染组高,料肉比仍明显比感染组低。预防1组的肠绒毛高度显著比其他组高(P<0.05);预防1组、预防2组肠绒毛高度与隐窝深度的比值也是显著比氯霉素预防组、感染组大(P<0.05),饲料中添加1%载铜凹凸棒石对空肠黏膜具有保护作用。在治疗效果试验中,饲料中添加1.5%载铜凹凸棒石使鸡的死亡率降低,肝脏、盲肠带菌数目比其他组较少,并且治疗2组的盲肠沙门氏菌数目显著比感染组低。治疗1组的平均终重和平均日增重比感染组高,说明饲料中添加1%载铜凹凸棒石缓解了生长缓慢。治疗2组肠绒毛高度和隐窝深度与空白组没有明显差异,并且治疗2组肠绒毛高度明显比感染组高(P<0.05),说明饲料中添加1.5%载铜凹凸棒石使肠道功能得到恢复。综合以上,饲料中添加1%、1.5%载铜凹凸棒石分别对鸡白痢有预防和治疗作用,降低盲肠、肝脏带菌数目,可以缓解肠绒毛萎缩现象,对空肠黏膜具有保护作用。最后,研究了载铜凹凸棒石对600只鸡腹泻的预防效果,结果表明,饲料中添加1%载铜凹凸棒石比添加0.2%和0.5%载铜凹凸棒石对雏鸡的腹泻效果好,并且可以从平均终重得出,饲料中添加0.2%和0.5%载铜凹凸棒石使鸡的平均终重提高,因此一定量载铜凹凸棒石可以有效的预防腹泻,提高平均终重。更多还原

【Abstract】 Salmonellosis is one of the most important infectious diseases of livestock and poultry industry.Antibiotics are used for the main treatment and prevention to forbid this diseases.But,due to the abuse of antibiotics,the drug-resistance of pathogenic bacteria becomes serious,so it is urgently need to find a medical material to assist or even replace antibiotics to prevent and treat pullorum disease.Copper has good antibacterial property,it can inhibit the growth of many pathogens,at the meantime,its inhibition of harmful fungi is also very prominent.Attapulgite has good adsorption.It has unique crystal structure and larger specific surface and it performes very well in terms of adsorption of bacterial and toxins.The both of advantages were combined in this experiment,and the attapulgite modified with copper was prepared as inorganic antibacterial,in order to preliminary study on theantibacterial mechanism of copper-modified attapulgite and research the prevention and treatment of salmonella pullorum dieases,so as to provide theoretical basis for a new drug to bacterial diarrhea.The first experiment was that preparation conditions of copper-modified attapulgite were optimized.It explorated influence of different treatment temperature and reaction temperature of appapulgite on copper loading and research of therapeutic effects of different copper-modified attapulgite on diarrhea in mice.The results showed that effect of the reaction temperature on copper loading is relatively large.When the reaction temperature was 90 ℃,the copper loading was the highest,which was 51.05 mg/g.Treatment temperature of attapulgite was 350 ℃ and 105 ℃,there was no significant change on copper loading.In the treatment of diarrhea in mice,the higher the amount of copper loading,the better the treatment effect of mice.when the treatment temperature of attapulgite was 350 ℃ and 105 ℃,there was similar to the therapeutic effect of the mice,in consideration of a large number of production,so we can change the temperature into 105 ℃.Secondly,the antibacterial properties and antibacterial mechanism of copper-modified attapulgite were preliminarily studied,choosing Salmonella pullorum as indicator bacteria.Different quality of copper-modified attapulgite had different bactericidal effect,increased with the increase of mass concentration,attapulgite only had bacterial adsorption ability;the amount of copper-modified attapulgite released did not change with time.Bacterial endoenzyme activity results showed that bacteria destroyed by copper-modified attapulgite,resulting in significant release of intracellular enzyme.The results showed that copper-modified attapulgite had strong bactericidal effect,and the antibacterial ability of copper-modified attapulgite had two aspects of synergistic effect:on the one hand was that the surface of copper-modified attapulgite adsorbed bacteria;on the other hand was that the released copper of attapulgite has inhibition and killing effect on bacteria.Then,prevention and treatment effect of copper-modified attapulgite were studied.In the experiment of preventive effects.The results showed that mortality of the prevent 1 group was lowest,and it significantly reduced the number of bacteria in the liver and the cecum and number of cecum of the prevent 1 group were markedly lower than that in infected group.Compared with infection group,the average final weight,average daily gain had no significant difference,but the ratio of feed and meat significantly decreased.The average daily gain of 1%in the late stage was significantly higher than that of the infected group,and the ratio of feed and neat was still lower than that of the infected group.This showed that the release of copper-modified attapulgite to ease the growth of Salmonella caused,the intestinal villus of the prevention 1 group was significantly higher than other groups(P<0.05),and compared with the normal group that was higher;ratio of intestinal villus height and crypt depth of the prevention 1 group and the prevention 2 group was significantly bigger than the prevention chloramphenicol group and infection group(P<0.05),1%copper-modified attapulgite improved intestinal cashmere wool height,to have the improvement function to the jejunal morphology.In treatment effect experiment,1.5%copper-modified attapulgite made cecal bacteria number of chicken mortality and liver less than other group and cecal Salmonella number of the treatment 2 group significantly lower than the infected group.The average final weight and average daily gain of the treatment 1 group were higher than those of the infected group,indicating that 1%copper-modified attapulgite alleviated the growth slowly.Intestinal villus height and crypt depth of the treatment 2 group and the blank group have no significant difference,and intestinal villus height of the treatment 2 group was significantly higher than the infection group(P<0.05),indicating that 1.5%copper-modified attapulgite made intestinal function recovery.The results show that 1%、1.5%of copper-modified attapulgite respectively had role the prevention and treatment of Salmonella pullorum,reducing the number of bacteria in liver and cecum,alleviating the slow growth,improving the intestinal villus height and jejunal morphology.Finally,Research on the prevention of diarrhea of copper-modified attapulgite in chickens.The results showed that 1%copper-modified attapulgite is better than 0.2%and 0.5%copper-modified attapulgite to diarrhea effect in chickens.It can from the average final weight obtained that 0.2%and 0.5%copper-modified attapulgite make chicken average final weight increase,so a certain amount of copper-modified attapulgite can effectively prevent diarrhea and improve the average final weight.更多还原