共查询到20条相似文献，搜索用时 26 毫秒
1.
Chicks infected with Salmonella typhimurium at 1 day of age were treated with normal intestinal flora starting 3 or 9 days later. Chicks were reared on the floor in isolated pens with wood shavings for litter. Cloacal-swab cultures were the main criteria for determining S. typhimurium infection. A single treatment reduced the infection period, but multiple treatments hastened the process considerably: after 6-8 weeks, birds given multiple treatments yielded sporadic or no isolations of S. typhimurium. It appears that litter from birds colonized by a protective microflora may serve as a vehicle for transmitting the flora to succeeding groups of birds. 相似文献
2.
A native intestinal microflora of chickens which is protective against salmonella readily transferred to penmates and apparently to birds in adjacent pens. The microflora not only minimized infection resulting from exposure following colonization of the gut with microflora, but significantly abbreviated the period of infection when introduced after a salmonella infection was established in chicks. A microflora with undiminished protective activity, sensitive to only a few commonly used antibacterials, was established in a SPF-Cofal/Marek-negative population. Intestinal microflora from mourning doves was at least partially effective in protecting chicks against a naladixic-acid-resistant strain of Salmonella infantis. In limited tests with 2 of 3 sources of protective microflora, the growth rate of chicks in the absence of salmonellae was significantly improved. A hypothesis involving specificity of attachment between the glycocalyces of the protective microflora and of the intestinal mucosa is offered as the likely mechanism of protection. 相似文献
3.
Comparative studies on competitive exclusion of three isolates of Campylobacter fetus subsp. jejuni in chickens by native gut microflora 总被引：3，自引：0，他引：3
Resistance of young chicks to Campylobacter fetus subsp. jejuni was substantially increased by early exposure to native gut microflora. Protection was demonstrated against two human isolates and a chicken isolate of C. fetus subsp. jejuni. Significant protection against the chicken isolate was observed throughout a 91-day test period. Infection reached 100% (25/25) in the untreated group at 56 days of age and only 4% (1/25) in the group treated with native gut microflora. Campylobacter fetus subsp. jejuni was isolated from the ceca and less frequently from the gall bladder and liver of chicks that actively shed the bacteria. Cultures of feces from chicks reared on wood-shavings litter were often negative, suggesting that culturing litter as an indicator of infection has limited value. 相似文献
4.
Adherence of salmonellae and native gut microflora to the gastrointestinal mucosa of chicks 总被引：4，自引：0，他引：4
Adherence of salmonellae to the mucosa of the cecum was demonstrated using scanning electron microscopy. In the absence of other microflora, adherence was also shown at all other levels of the alimentary tract tested. Comparative development of native gut microflora in the ceca was also investigated in chicks treated with selected fecal microflora and in untreated chicks using scanning electron microscopy. In the treated chicks, there was early colonization by adherent bacteria interconnected with fibers, forming a mat of microflora. This mat of microflora may be responsible for preventing colonization of salmonellae in the ceca. 相似文献
5.
在对雏鸡人工感染柔嫩艾美耳球虫后6、8、13、20天,分别对感染雏与未感染雏盲肠内容物中梭杆菌、真杆菌、消化球菌、乳酸杆菌、类杆菌、肠球菌、葡萄球菌和肠杆菌等8种主要正常菌群进行定性、定量分析。结果发现在球虫感染第20天,感染组有益菌如乳酸杆菌的数量低于对照组,差异极显著(P<0.01),有害菌如梭杆菌、葡萄球菌数量感染组高于对照组,其中梭杆菌差异显著(P<0.05),葡萄球菌差异极显著(P<0.01)。 相似文献
6.
为了解析外源基因的转入对动物生长特性、组织中脂肪酸含量和肠道菌群分布的影响,该研究以FAD3基因编辑小鼠为试验组,以BDF1小鼠为对照组,在相同条件下饲养至45日龄处死,检测两组小鼠体重、各器官重量、肌肉中不饱和脂肪酸含量,并利用PCR-DGGE方法在16S rDNA的V3领域检测小鼠盲肠菌群分布。结果显示,FAD3组小鼠肝脏重量显著（P<0.05）低于对照组,其他各内脏器官重量和体重两组均无显著（P>0.05）差异。FAD3组小鼠肌肉中n-6多不饱和脂肪酸（PUFAs）含量低于对照组,但无显著（P>0.05）差异,而n-3 PUFAs含量显著（P<0.05）高于对照组。两组小鼠盲肠菌群分布个体差异大,未观测到明显的组间差异,Anaerotaenia torta为共同的优势菌,而Flavonifractor plautii可能为FAD3组小鼠特有菌。该试验结果提示,外源基因FAD3的引入对小鼠生长性能和盲肠菌群的影响较小,可提升肌肉中n-3多不饱和脂肪酸含量。 相似文献
7.
Protection of chicks against salmonella infection induced by spray application of intestinal microflora in the hatchery 总被引：4，自引：0，他引：4
The efficacy of spray application of intestinal microflora of the adult bird in protection of broilers against salmonella infections was studied in 3 experiments under laboratory and field conditions. In chicks treated soon after hatching (in the hatchers at approximately 30 per cent hatch or in the chick delivery boxes in the hatchery) with crop-caecum homogenate or a mixture of aerobically and strict anaerobically cultured intestinal flora, very good results were achieved. A very obvious protective effect against a high infection dose (3 X 10(6) c.f.u.S. infantis bacteria per chick) and complete protection against natural infection with different salmonella types was induced. A significant improvement of growth rate was observed in broilers treated by spray in the hatchery and reared for 7 weeks under field conditions in an environment heavily contaminated with different salmonella types. 相似文献
8.
本研究旨在通过网络药理学联合16S rDNA高通量测序技术分析丹参对感染大肠杆菌小鼠肠道菌群的影响。利用传统中药系统药理学数据库和分析平台（TCMSP）筛选丹参有效成分及靶点基因。使用基因数据库（Genecards）获得E.coli靶点基因。两者靶点基因取交集,通过STRING平台进行蛋白质相互作用分析,构建PPI网络,并运用Cytoscape 3.8.2软件构建“丹参活性成分-潜在作用靶点”网络。利用DAVID在线工具进行基因本体论（GO）功能富集分析,Metascape数据库进行京都基因与基因组百科全书（KEGG）通路富集分析。试验选用110只雄性昆明小鼠,随机分为对照组、大肠杆菌组和低、中、高剂量丹参大肠杆菌感染组,每组22只。连续灌胃丹参液28 d后,用E.coli O101进行腹腔注射,对照组注射无菌生理盐水,观察24 h后,收集各组粪便。应用16S rDNA高通量测序技术对各组小鼠肠道菌群进行分析。结果显示：1）网络药理学丹参有效成分36个,作用靶点669个,Genecards数据库搜索E.coli靶点8 902个,对两者取交集去除孤立点获得丹参治疗E.coli潜在靶点51个;GO、KEGG分析,获得关键靶点18个、关键通路47条,其中生物过程（BP）、分子功能（MF）和细胞成分（CC）各为174、76、45条;2）通过Illumina Miseq测序共获得950 855条有效序列,2 537个操作分类单元（OTUs）;3） Alpha多样性分析结果表明,不同剂量丹参组肠道菌群多样性与对照组具有显著差异,大肠杆菌组肠道菌群多样性显著低于对照组（P<0.05）;4）相比于大肠杆菌感染组,在门水平上,低、中、高剂量丹参大肠杆菌感染组Bacteroidetes （拟杆菌门）丰度极显著增高（P<0.01）,Firmicutes （厚壁菌门）丰度显著增高（P<0.05）,Proteobacteria （变形菌门）极显著降低（P<0.01）,在属水平上Bacteroides（拟杆菌属）丰度极显著增高（P<0.01）;5）基于LEfSe分析,对照组、大肠杆菌感染组、丹参高剂量大肠杆菌感染组共发现14种显著差异菌群;6） PICRUSt功能预测分析发现,丹参对大肠杆菌感染小鼠肠道菌群调节功能主要富集的途径是氨基酸、碳水化合物运输与代谢,翻译、核糖体结构和生物转化,细胞壁/膜/生物合成等方面。综上,基于网络药理学联合16S rDNA高通量测序技术全面揭示了丹参多成分、多靶点、多途径调节相关菌群生物丰富度,对大肠杆菌感染小鼠的肠道菌群紊乱有缓解作用,为临床应用丹参治疗大肠杆菌感染提供理论依据。 相似文献
9.
选取48羽7日龄艾维茵肉公鸡随机分为对照组和试验组,试验组动物房内每日8时喷雾1mL/m3的枯草芽孢杆菌Pab02制剂（108 CFU/mL）,对照组同法喷雾100mL蒸馏水。28日龄时对肉鸡测体质量,采用活菌计数法和PCR-DGGE法对28,49日龄肉鸡呼吸道菌群进行检测,石蜡组织切片法对肺部结构进行观察。结果显示,喷雾枯草芽孢杆菌Pab02对28日龄肉鸡的采食量、日增重、料肉比等生长性能有所提高,但不显著（P〉0.05）;喷雾Pab02能增加49日龄呼吸道细菌数量（P〈0.01）,提高同一生态位菌群的稳定性和呼吸道菌群的多样性;Pab02喷雾剂不引起肺组织损伤,能使淋巴小结增多。结果表明,芽孢杆菌Pab02喷雾剂不能显著改善肉鸡的生长性能,但是能调节呼吸道菌群的结构,增强肺脏的免疫功能。 相似文献
10.
Reciprocal competitive exclusion of salmonella and Escherichia coli by native intestinal microflora of the chicken and turkey 总被引：2，自引：0，他引：2
Both the native intestinal microflora of chickens that protected chicks against salmonellae and Escherichia coli and native turkey intestinal microflora were evaluated for their reciprocal protective capacity in both species against Salmonella typhimurium and a pathogenic strain of E. coli. Nalidixic-acid-resistant forms of the S. typhimurium and E. coli strains were used in seeder-bird and individual-bird challenge tests. Reciprocal protection was provided by native chicken and turkey intestinal microflora in chicks and poults against S. typhimurium and the pathogenic strain of E. coli. The chicken and turkey microflora appeared to be equally effective in protecting the two species from S. typhimurium, but protection against E. coli was somewhat greater in the chicken than in the turkey. 相似文献
11.
试验旨在研究核桃青皮水提物对肉鸡肠道微生物菌群丰度和多样性的影响,初步揭示核桃青皮水提物对肉鸡肠道微生物菌群结构的影响。选取240只1日龄本地土杂鸡,随机分为2组,1个对照组和1个试验组,每个组设4个重复,每个重复30只。试验组于28日龄开始在饮水中添加核桃青皮水提物,6周后,每个重复采集10份肉鸡肛门棉拭子,利用Illumina Miseq测序平台对微生物16S rDNA V3-V4区扩增产物进行双端测序,分析微生物群落结构多样性。高通量测序结果显示,所有样本共含有个17菌门和48个菌属;多样性指数分析结果表明,饲喂核桃青皮水提物的肉鸡肠道菌群丰富度增加。从门水平分析,厚壁菌门（Firmicutes）丰度升高了2.21%（P > 0.05）,变形杆菌门（Proteobacteria）丰度降低了2.22%（P > 0.05）;从属水平上分析,大肠杆菌属（Escherichia）丰度降低了5.35%（P < 0.05）,肠球菌属（Enterococcus）丰度升高了9.63%（P < 0.05）。本研究结果表明,饲喂核桃青皮水提物后肉鸡肠道菌群多样性显著增加（P < 0.05）,据此推测,核桃青皮水提物能有效调节肉鸡肠道菌群并有益于肠道健康。 相似文献
12.
为研究微生态产品对奶牛采食量、乳品质、肠道菌群的影响,选取胎次、年龄、泌乳天数及生理性状相近的荷斯坦牛216头,分为试验A组（美国公司某产品）、试验B组（益倍健1801）、对照组,每组72头,各组基础日粮一致,试验组按照5kg/t比例添加产品,试验期45d。结果表明,两个试验组奶牛采食量、日产奶量、乳蛋白含量、乳脂率、肠道菌群多样性均高于对照组（P〉0.05）,体细胞数显著低于对照组（P〈0.05）,其中B组日产奶量、乳蛋白含量、肠道菌群多样性高于A组（P〉0.05）,采食量、乳脂率略低于A组（P〉0.05）。 相似文献
13.
To determine the most appropriate dose in drinking water of the disinfectant N-alkyl dimethyl benzyl ammonium chloride (TIMSEN), a fowl typhoid challenge trial was carried out using 21-day-old Salmonella-free chickens. In a pretrial, performed with six groups of 10 chickens each, it was shown that the disinfectant was atoxic and safe when administered during 15 days at doses of 0 ppm, 200 ppm, 400 ppm, 800 ppm, 1600 ppm, or 3200 ppm. Thereafter, a challenge trial was performed with 390 chickens divided into six groups of 65 birds each. Chickens were treated during 9 days with oral doses of 0 ppm, 25 ppm, 50 ppm, 100 ppm, 250 ppm, and 500 ppm (groups identified as A, B, C, D, E, and F, respectively). Twenty-four hours after the beginning of the treatment, 30 chickens of each group were orally inoculated with 10(9) colony-forming units of Salmonella Gallinarum strain INTA 91 per bird. The remaining 35 unchallenged chickens from each group were left in the same cage in close contact with the other challenged birds of their group. All surviving chickens were sacrificed 8 days after challenge. Livers from all birds were examined for the presence of Salmonella Gallinarum. Salmonella Gallinarum was isolated from all challenged chickens and from some unchallenged chickens of groups A (4/35), E (3/35), and F (6/35), but not from any unchallenged chicken from groups B, C, and D. Doses of 50 ppm (group C) significantly reduced mortality (30%) in comparison with the untreated control group A (65%). Mortality in group B (45%) was not significantly different from group C. Administration of higher doses of the disinfectant resulted in significantly higher mortality rates, 70% in group E and 85% in groups D and F. Increased infection and mortality rates of groups D, E, and F might have been caused by inhibition of the protective action of the normal gut flora. To reduce horizontal infection and mortality, the manufacturer's prescribed oral dose of 25 ppm may be increased up to 50 ppm. Nevertheless, higher doses should be avoided because they may cause horizontal increased spread of the disease and mortality. 相似文献
14.
E. Goren W. A. de Jong P. Doornenbal J. P. Koopman H. M. Kennis 《The Veterinary quarterly》2013,33(2):73-79
Summary The efficacy of spray application of intestinal microflora of the adult bird in protection of broilers against salmonella infections was studied in 3 experiments under laboratory and field conditions. In chicks treated soon after hatching (in the hatchers at approximately 30 per cent hatch or in the chick delivery boxes in the hatchery) with crop‐caecum homogenate or a mixture of aerobically and strict anaerobically cultured intestinal flora, very good results were achieved. A very obvious protective effect against a high infection dose (3 × 10 c.f.u. S. infantis bacteria per chick) and complete protection against natural infection with different salmonella types was induced. A significant improvement of growth rate was observed in broilers treated by spray in the hatchery and reared for 7 weeks under field conditions in an environment heavily contaminated with different salmonella types. 相似文献
15.
Effect of oxytetracycline therapy on experimentally induced pneumonic pasteurellosis in lambs 总被引：1，自引：0，他引：1
Two groups of 10, specific pathogen free lambs were injected with a long acting oxytetracycline preparation at a dose rate of 20 mg/kg either 24 hours before or 24 hours after exposure to an aerosol of Pasteurella haemolytica. When compared with the response of similarly infected but untreated lambs, the effect of pretreatment was to postpone the appearance of clinical signs of pneumonia for four days and the deaths of five lambs for five to six days post infection, by which time seven untreated lambs had died. Treatment 24 hours after infection caused a rapid clinical recovery which persisted until six days after infection but two treated lambs died seven days after infection. Lung lesions in the group treated after infection were significantly less extensive than those in the untreated lambs. 相似文献
16.
Chicks monocolonized by either salmonellae or pathogenic strains of Escherichia coli had persistent and undiminished colonization of all levels of the gastrointestinal tract and frequently had bacteremia during test periods ranging to 35 days. Poults monocolonized by salmonellae or Arizona hinshawii 7:"1,7,8 developed a similar pattern of colonization. Conventionally reared chicks and poults had rather variable colonization by these pathogens, and it was most persistent in the ceca. Groups treated with a native protective microflora were infrequently colonized. Differences in colonization are explainable by lack of competing bacteria in the monocolonized group and by various degrees of protection provided by microflora colonizing the other groups. 相似文献
17.
Taylor MA Marshall RN Marshall JA Catchpole J Bartram D 《Veterinary parasitology》2011,178(1-2):48-57
Twin lambs at pasture with their ewes, were divided into seven groups of 10 lambs. One group of 10 lambs served as a non-infected, untreated control. Five groups of 10 lambs were infected with 10,000 oocysts of Eimeria crandallis and 10,000 oocysts of Eimeria ovinoidalis when they were 3 weeks old (day 21 of the study). This produced a good level of infection with high oocysts production and diarrhoea in the lambs. Fourteen days after the primary, artificial challenge (day 35) four of these groups were treated with oral diclazuril at 0.25, 1.0, 2.0 or 4.0mg/kg. Diclazuril treatment was highly effective, dramatically reducing symptoms of diarrhoea and reducing faecal oocyst output by 79.7%, 97.3%, 99.4% and 99.5% respectively in the treated groups within four days. Two weeks post-treatment, and 28 days after the primary coccidial challenge (day 49 of the study), five groups of lambs were re-challenged with 100,000 oocysts of E. crandallis and 100,000 oocysts of E. ovinoidalis (secondary challenge). A group of lambs which had received neither the primary coccidia infection, nor drug treatment (susceptible controls) were also given the secondary challenge. All lambs given the secondary challenge produced high numbers of coccidia and exhibited varying degrees of diarrhoeic faeces. The lambs, which had previously received the higher doses of diclazuril at 2.0 and 4.0mg/kg, developed clinical signs of coccidiosis. These lambs were completely susceptible despite having received the early primary immunising infection of coccidia on day 21. The effects of the secondary challenge were more severe in the groups dosed with the two highest levels of diclazuril than in the susceptible control lambs, which had presumably been exposed to continued low levels of pasture contamination and had acquired a limited degree of immunity from this exposure. It would appear that treatment at the higher dose levels not only eliminated most of the oocysts from the primary challenge but also adventitious infection derived from the grazing paddocks. In contrast, lambs which had received the two lower drug levels of diclazuril (0.25 and 1.0mg/kg) whilst producing large numbers of oocysts, had only transient diarrhoea following secondary challenge. It was concluded that when used as a metaphylactic treatment, diclazuril works rapidly and is effective within four days of administration. Overall, a single dose of diclazuril at either 0.25-1.0mg/kg appears to be highly effective in the control of coccidiosis in young lambs at pasture whilst allowing the development of protective immunity against subsequent heavy coccidia challenge. 相似文献
18.
SUMMARY Three groups of 8, 4-month-old male Jersey or Jersey-cross calves were infected with 2400 Dictyocaulus viviparus L3 larvae and either left untreated or injected subcutaneously with 200 μg/kg doramectin 5 or 25 days after infection (DAI). Lungworms were found in all untreated cattle (geometric mean = 49) at necropsy 39 or 40 DAI. None was found in any of the treated cattle. In a second experiment, groups of 6, 8-month-old calves were untreated or injected with 200 μg/kg doramectin 28, 21 or 14 days before each calf was challenged with 2700 D viviparus larvae. Lungworms were recovered at necropsy 32 to 34 DAI. The geometric mean worm burden in the untreated cattle was 550. This was reduced by 100%, 99.5% and 94.1% in calves treated with doramectin 14, 21 or 28 days, respectively, before infection. It was concluded that doramectin is a highly effective anthelmintic against D viviparus adult or L4 infections of cattle, and that reinfection of treated cattle will be significantly reduced for at least 28 days after treatment. 相似文献
19.
20.
The effect of immunosuppression on protective immunity of turkey poults against infection with turkey coronavirus 总被引：2，自引：0，他引：2
Loa CC Lin TL Wu CC Bryan T Hooper T Schrader D 《Comparative immunology, microbiology and infectious diseases》2002,25(2):127-138
The objective of the present study was to evaluate the protective effect of humoral and cellular immunities on turkeys infected with turkey coronavirus (TCV). Two trials were conducted with two separate hatches of turkey poults. Turkey's were experimentally immunosuppressed with cyclosporin A (CsA) or cyclophosphamide (CY) and infected with TCV. Prior to infection, treatment with CsA selectively suppressed T cell activity as revealed by 2-3 fold decreased (p < 0.1) lymphocyte proliferation responses to a T cell mitogen, concanavalin A (Con A). Treatment with CY mainly induced B cell deficiency as indicated by significant reductions (p < 0.05) in antibody responses to sheep erythrocytes 7 days after injection. Body weight gain of turkeys treated with CY was significantly lower (p < 0.05) than that of untreated turkeys at 9 days post-infection (PI). Turkeys treated with CY had 1-2 fold higher immunofluorescent antibody assay (IFA) scores for TCV antigens (p < 0.05) in the intestine than untreated turkeys at 9 or 14 days PI. These results suggested that humoral immunity against TCV infection may be important in turkeys. 相似文献