复合微生态制剂对雏鸡实验性感染鸡白痢沙门菌病的预防实验

实验用200羽伊莎B-380雏鸡,随机分为5组,在1~3组雏鸡日粮中分别添加0.5%、1.0%、1.5%HM-强效复合微生态制剂,第4组日粮中添加0.2%氟哌酸,第5组饲料中不添加任何药物作为空白对照,用鸡白痢沙门菌进行人工感染,以观其药物的保护作用。结果显示添加0.5%HM-强效复合微生态制剂有98%的保护率,添加1.0%、1.5%HM-强效复合微生态制剂和添加0.2%氟哌酸有100%的保护率,检查发现添加HM-强效复合微生态制剂组雏鸡肠道中大肠埃希菌明显减少,而乳酸杆菌和双歧杆菌有益微生物明显增多。     

鸡源抑菌性乳酸菌的特性研究与鉴定及饲喂肉仔鸡的效果研究

目的对笼养蛋鸡盲肠中的优良乳酸菌进行筛选、鉴定,并饲喂肉雏鸡,研究同源乳酸菌作为微生态制剂的生物学特性。方法通过生长、产酸曲线,耐酸耐胆盐测定及16SrDNA分子鉴定,对实验乳酸菌进行生物学特性研究和鉴定。采用单因素试验设计,选1日龄健康肉公雏鸡180只,随机分成3组。试验组Ⅰ:饲喂基础饲粮;试验组Ⅱ:基础饲粮+0.01%黄霉素;试验组Ⅲ:基础饲粮+0.2%CCL30菌制剂。饲喂28d,研究乳酸菌制剂对肉仔鸡的促生长特性。结果从鸡盲肠中分离的乳酸菌CCL30生长迅速、产酸能力强、耐酸耐胆盐消化,鉴定为Lactobacillus plantarum(植物乳杆菌)。雏鸡饲养实验结果显示,饲粮中添加乳酸菌制剂可提高肉雏鸡日增重,显著降低饲料转化率,与抗生素组比较差异无统计学意义,且乳酸菌制剂能显著增加盲肠内乳酸菌的数量,有效抑制盲肠内大肠埃希菌的繁殖(P0.05)。结论同源乳酸菌制剂对肉雏鸡的生长具有促进作用,有同于抗生素的抑菌作用,且乳酸菌制剂具有安全优势,可替代抗生素作为鸡用微生态制剂应用。     

应用整肠生防治鸡感染腹泻的实验研究

整肠生是我所研制生产、发明的微生态制剂。它是利用BL 2 0 386株地衣芽胞杆菌制成的微生态活菌制剂。为探讨整肠生对沙门菌、致病性大肠杆菌的致病作用以及肠道菌群失调性腹泻的防治效果 ,我们特在齐齐哈尔市地区所属的养鸡场应用该制剂进行了鸡感染性腹泻的研究。经过实验观察认为 ,整肠生防治鸡的感染性腹泻疗效显著、可靠 ,优于过去常用的治疗药物和活菌制剂促菌生 ,而且对于雏鸡、育成鸡的的发育成长明显的高于其他对照组 ,提高了各龄鸡的成活率。我们应用整肠生防治鸡的感染性腹泻收到了较好的效果 ,提高了经济效益和社会效益。1　材…     

复合微生态制剂对断奶仔猪生产性能、粪便菌群及血液指标的影响

目的 探讨复合微生态制剂对断奶仔猪生长性能、粪便乳酸菌和大肠埃希菌数、血液红胞数以及血红蛋白含量及其对免疫水平的影响.方法 选择25日龄的断奶仔猪共108头,平均分为两组:Ⅰ组和Ⅱ组,每组3个重复,每个重复18只,Ⅰ组饲喂全价料+2.0‰复合微生态制剂;Ⅱ组为对照组,饲喂全价料,实验期为42 d.结果 至实验结束时,复合微生态制剂组的料重比显著低于对照组(P ＜0.05);14、28和42 d时复合微生态制剂组粪便中的大肠埃希菌数比对照组低7.94％,2.90％和4.89％,与对照组相比差异有统计学意义(P＜0.05);14d时,复合微生态制剂组粪便乳酸菌数与对照组相比差异有统计学意义(P＜0.05),28和42 d时,两组粪便乳酸菌数差异无统计学意义(P＞0.05).14、28和42 d时复合微生态制剂组血液中红细胞数和血红蛋白浓度均显著高于对照组.两组血清尿素氮水平差异无统计学意义(P＞0.05),复合微生态制剂组血清总蛋白和IgG的含量与对照组相比有升高的趋势,但差异无统计学意义(P＞0.05),复合微生态制剂组血清IgA和IgM的浓度显著高于对照组(P＜0.05).结论 复合微生态制剂可以显著降低断奶仔猪的料重比,降低粪便中大肠埃希菌数量,促进血液红细胞和血红蛋白的含量,提高断奶仔猪的免疫水平.     

小鼠感染细小病毒的临床特征分析

目的分析小鼠细小病毒(MVM)在人工感染小鼠体内的分布规律、排毒和抗体变化,以及自然条件下小鼠感染MVM的情况。方法对33只BALB/c小鼠腹腔接种0.2 m L MVM悬浮液,每天观察动物的外观、行为、饮食和精神状态,在接种第0~60天共12个时间点各对2~3只动物进行安乐死,并采取组织、粪便和血清样本进行检测。荧光定量PCR(QPCR)方法检测组织和粪便的病毒核酸,ELISA方法检测血清抗体。同时,采取100只SPF小鼠、76只开放饲养小鼠检测MVM核酸,采取1463只SPF小鼠、82只开放饲养小鼠检测MVM抗体。结果实验小鼠接种MVM后外观、行为、饮食和精神状态未见异常,剖检无明显病变。各组织在接种后都能检出病毒核酸,并在接种后4~7 d达到峰值,且到60 d仍可检出病毒核酸。各组织间比较,病毒峰值最高的组织是肝,其次是肾、脾、胃、心脏、肺、盲肠和脑。粪便排毒在接种后11 d可达到峰值,之后迅速下降,但到60 d还可检到。血清抗体在病毒接种后7 d开始产生,之后抗体效价逐渐升高,21 d就可以达到32倍左右,之后至60 d一直处于64倍左右。临床样本中,核酸检测SPF小鼠未检出,开放饲养小鼠的检测阳性率为14.5%,经过测序比较确认为MVM病毒感染;抗体检测SPF小鼠有较低的检出率(0.3%),开放饲养小鼠检出率为68.3%。结论 MVM感染小鼠后一般呈隐性感染状态,可长期排毒,主要组织脏器、粪便、血清都能用于MVM的检测,实验小鼠感染MVM可以通过病毒核酸和血清抗体检测方法进行病原检测。     

微生态防治控制禽副伤寒沙门氏菌感染

近年来,国外许多学者已经把一种称为竞争排斥(Competitive Exclusion,CE)理论的微生态防治方法引入对禽副伤寒沙门氏菌感染的控制。把一个或多个无沙门氏菌感染的成年鸡肠道菌群(通常是盲肠菌群)经口引入新生小鸡就可使小鸡肠道菌群得以改善,从而提高小鸡对沙门氏菌感染的抵抗力。1982年,Pivnick等对CE理论作了进一步阐述,要点如下:新生小鸡可被单个沙门氏菌感染,而年龄较大的鸡对沙门氏菌感染有抵抗力。如果把成年鸡的肠菌群引入几日龄小鸡,可加速其肠道菌群的演替过程,沙门氏菌被迅速排斥从而提高了鸡对沙门氏菌感染的抵抗力。导入的菌群中必须无沙门氏杆菌,否则就不能起到控制沙门氏菌感染的作用。     

沙门菌感染后0至5岁婴幼儿肠道微生物群落

目的比较0至5岁沙门菌感染和健康婴幼儿的肠道菌群分布特点,研究沙门菌感染导致的婴幼儿肠道菌群微生态失调情况,为腹泻病的发病机制和防治提供微生态学理论依据。方法采集9例沙门菌腹泻婴幼儿(腹泻组)与11例健康婴幼儿(健康组)的粪便样本,通过16S扩增子测序分析肠道菌群的多样性,并比较2组样本的群落结构差异,研究沙门菌对婴幼儿肠道微生态的影响。结果腹泻组婴幼儿粪便样本的Shannon指数显著低于健康组(2.261 1 vs 4.069 9,t=-4.892 0,P=0.001 0),Simpson指数也显著低于健康组(0.562 9 vs 0.873 3,t=-3.721 0,P=0.006 0)。腹泻组婴幼儿粪便样本的变形菌门(Proteobacteria)丰富度显著高于健康组(t=0.035 7,P=0.009 2),而厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)丰富度显著低于健康组(t=0.115 4,P=0.044 6;t=0.035 7,P=0.007 0)。腹泻组婴幼儿粪便样本的人类疾病(human diseases)功能的基因丰富度显著高于健康组(t=0.131 5,P=0.026 0),而新陈代谢(metabolism)功能和生物体系统(organismal systems)功能的基因丰富度显著低于健康组(t=0.099 1,P=0.009 8;t=0.142 9,P=0.046 3)。结论沙门菌降低了婴幼儿肠道菌群的多样性,改变了肠道菌群的群落结构,并调控机体功能的基因表达。细菌性腹泻与病原菌侵袭、肠道微生态失衡及机体功能密切相关。     

林麝复合微生物制剂的研制

本研究采用林麝肠道分离的3株乳酸菌研制一种复合微生态制剂,对复合微生态制剂进行了不同配比的选择、昆明小鼠安全性试验、活菌数的监测和林麝的应用。结果显示:作为最优配比的复合微生态制剂C(S2∶S3∶MRS2-2=1∶1∶2),安全性试验结果显示其未引起小白鼠机体的不良反应;在14 d时,储存温度为-20℃下复合微生态制剂的活菌数降至1.43E+08 CFU/m L;用复合微生态制剂C治疗林麝肠道致病性大肠杆菌感染的昆明小鼠,结果显示微生态制剂组肠道乳酸菌显著大于空白组和感染组(P0.05),复合微生态制剂治疗腹泻林麝,治愈率为50%。本试验首次研制了一种林麝复合微生态制剂,对于提高林麝人工养殖的存活率有指导意义。     

rOmpF和OMVs亚单位疫苗可有效预防家禽感染肠炎沙门菌

正肠炎血清型沙门菌仍然是人类沙门菌感染病最常见的血清型,可通过受污染的食品(特别是家禽产品)感染人体。研制肠炎沙门菌亚单位疫苗不仅可以保护鸡免受沙门菌感染,还能切断沙门菌传染源。本研究分别以重组表达的外膜蛋白F (rOmpF)和提取的外膜囊泡(OMVs)制备了两种肠炎沙门菌亚单位疫苗,并在鸡中进行了肠炎沙门菌攻毒试验。结果显示,制备的亚单位疫苗不仅能诱导鸡体内产生抗体,还能引起较强的细胞免疫应答。     

复合型菌剂对鸡白痢菌的抑制作用及其各菌在鸡体内定居情况

利用由鸡粪肠球菌、鸡非致病性大肠埃希菌、芽胞杆菌、酵母菌和乳酸菌组成的复合菌剂在体外与鸡白痢沙菌门作用,结果表明,鸡白痢沙门菌生长明显受到抑制,抑制率达90％以上。并且还测定其各菌的有关生物特性以及雏鸡体内的定居情况：胆盐耐受范围在1.2%-1.4%之间;苯酚耐受范围在0.1%－0.2%之间;耐酸范围在pH3.0-2.5之间;在雏鸡体内除芽胞杆菌为过路菌外,其他菌均可定居于盲肠、中肠、肌胃、素囊中。     

Efficiency of various bacterial suspensions derived from cecal floras of conventional chickens in reducing the population level of Salmonella typhimurium in gnotobiotic mice and chicken intestines

The antagonistic effect exerted towards Salmonella typhimurium by the flora issued from conventional chickens was studied in gnotobiotic animals. In germfree chickens and mice inoculated with S. typhimurium, the highest bacterial counts were observed in ceca, and were not significantly different in either host. The protection afforded by the inoculation of cecal flora issued from a conventional chicken was more effective when this flora was inoculated first into germfree chickens than when it was given only after inoculation with S. typhimurium. Administration of a cecal flora from a 15-day-old chick to gnotobiotic mice and chicken resulted in the inhibition of a further intestinal colonization by S. typhimurium in both hosts. Sixteen strains were isolated among the predominant populations of the fecal flora from chicken flora recipient mice. Association of 14 strains of strictly anaerobic bacteria with 2 strains of Escherichia coli and Streptococcus faecium only decreased the number of S. typhimurium in the ileum of gnotobiotic mice, but not in their cecum. Anaerobe cultures were obtained from 10(-6) and 10(-8) dilutions prepared from the fecal flora of gnotobiotic recipient mice. Antagonistic bacteria were present only in cultures from the 10(-6) dilution. Cecal concentrations of volatile fatty acids were shown not to be the sole factor implicated in the antagonistic effect against S. typhimurium.     

Significance of the bacteriophage treatment schedule in reducing salmonella colonization of poultry

Salmonella remains the major cause of food-borne diseases worldwide, with chickens known to be the main reservoir for this zoonotic pathogen. Among the many approaches to reducing Salmonella colonization of broilers, bacteriophage offers several advantages. In this study, three bacteriophages (UAB_Phi20, UAB_Phi78, and UAB_Phi87) obtained from our collection that exhibited a broad host range against Salmonella enterica serovar Enteritidis and Salmonella enterica serovar Typhimurium were characterized with respect to morphology, genome size, and restriction patterns. A cocktail composed of the three bacteriophages was more effective in promoting the lysis of S. Enteritidis and S. Typhimurium cultures than any of the three bacteriophages alone. In addition, the cocktail was able to lyse the Salmonella enterica serovars Virchow, Hadar, and Infantis. The effectiveness of the bacteriophage cocktail in reducing the concentration of S. Typhimurium was tested in two animal models using different treatment schedules. In the mouse model, 50% survival was obtained when the cocktail was administered simultaneously with bacterial infection and again at 6, 24, and 30 h postinfection. Likewise, in the White Leghorn chicken specific-pathogen-free (SPF) model, the best results, defined as a reduction of Salmonella concentration in the chicken cecum, were obtained when the bacteriophage cocktail was administered 1 day before or just after bacterial infection and then again on different days postinfection. Our results show that frequent treatment of the chickens with bacteriophage, and especially prior to colonization of the intestinal tract by Salmonella, is required to achieve effective bacterial reduction over time.     

Effects of dietary antibiotics on intestinal microflora in broiler chickens

Changes were examined in the intestinal microflora in broiler chickens fed a diet containing antibiotics to obtain fundamental information on the mechanisms of beneficial effect of the antibiotics upon livestock production. Three antibiotics (colistin, bacitracin, and enramycin) were employed as feed additives. Experiments were conducted with broiler chickens in two ways. In one way dietary antibiotics were fed continually at levels approved for use as feed additives for a long term. In the other they were fed the same antibiotics for a short term. Significant changes in microflora were observed mainly in such bacterial groups as aerobic bacteria and Lactobacillus. In the long term administration, three possible modes of variance in the bacterial flora were postulated: Changes directly related to the antibacterial spectrum of antibiotics. Antagonistic changes related to an ecological balance in the bacterial flora. Changes in quantitative balance of bacteria constituting each bacterial group. The change in the intestinal microflora during administration of the antibiotic diet was expressed as a complex form of these transition modes. In the short term administration, it was demonstrated that the effect of the antibiotic diet lingered even 7 days after administration. This suggests that antibiotics used as feed additives may possibly affect the stability of the intestinal microflora.     

Colonization of chicken cecae by Escherichia coli associated with hemorrhagic colitis.

Bacterial enumeration, histologic examination, and immunoperoxidase staining demonstrated the ability of an Escherichia coli strain associated with hemorrhagic colitis (serotype O157:H7) to colonize chicken cecae for up to 90 days postinoculation after a peroral challenge at 1 day of age. The bacteria induced mild, transient, mucous membrane damage confined to the proximal cecae of healthy, normal-appearing chickens, principally at 14 to 28 days postinoculation. Attachment, effacement, and penetration of the cecal surface epithelium by E. coli O157:H7 were observed. With the exception of splenic, hepatic, and cecal tonsil immune-related changes and cecal damage and colonization, no other organ systems or portions of the gastrointestinal tract were affected by the bacteria. Bacterial counts indicated that E. coli O157:H7 was predominantly present in the cecae (often at levels greater than 10(6) CFU/g of tissue and contents) and to a lesser extent in the colon. Our results suggest that E. coli O157:H7 colonizes chicken cecae and is passed through the colon with fecal excrement. The ability of this organism to colonize chicken cecae indicates that chickens may serve as hosts and possibly as reservoirs for E. coli O157:H7.     

An Epidemic of Salmonella Infantis Infection in Finnish Broiler Chickens in 1975–76

A large S. infantis infection epidemic in broiler chickens was studied during a period of one year. The outbreak affected three broiler producing companies in Finland. The infection spread to breeding farms according to available data during the summer of 1975. The epidemic still prevailed at the end of the studies on the farms of certain companies. The origin of the infection and the means of its spreading could not be ascertained. Some epidemiological evidence suggesting that a hatchery might have spread the infection was found. Contaminated feed may also have been involved, although the findings do not support feed as the principal vehicle in the epidemic. A complex pattern of transmission is most probable. A microbiological preventive method based on the feeding of a culture of intestinal flora of adult chickens to newly hatched broiler chickens was used on many farms in the study. The feeding of the culture lowered the proportion of infected flocks on the farms and significantly lowered the number of infected birds in those flocks, where the prevention was not complete. kw|Keywords|k]Salmonella infantis; k]infection; k]epidemic; k]broiler chicken     

Selection of lactobacilli for chicken probiotic adjuncts

During inhibitory activity screening of 296 strains of lactic acid bacteria from the gastro-intestinal tract of chicks, 77 strains showed inhibition against enteric indicator strains ( Salmonella enteritidis and Escherichia coli ). Eight different strains identified as Lactobacillus salivarius were selected for the following attributes: their ability to inhibit all the indicator strains; a high adhesion efficiency to the epithelial cells of chickens and also their resistance to a number of antibiotics, monensin, bile salts and pH 3·0. The inhibitory action was not affected by the addition of catalase and no inhibition was detected after neutralizing the supernatant culture fluid. The competitiveness of the most promising strains, Lact. salivarius CTC2183 and CTC2197, was assessed in chicken feed mixture and in vivo . It was concluded that both strains were capable of becoming predominant over the indigenous flora in the incubated chicken feed mixture. In vivo tests showed that Lact. salivarius CTC2197 was able to colonize and overcome Lact. salivarius CTC2183 and the indigenous flora in the crop and caecum of the inoculated chicks.     

Selection of lactobacilli for chicken probiotic adjuncts

During inhibitory activity screening of 296 strains of lactic acid bacteria from the gastro-intestinal tract of chicks, 77 strains showed inhibition against enteric indicator strains (Salmonella enteritidis and Escherichia coli). Eight different strains identified as Lactobacillus salivarius were selected for the following attributes: their ability to inhibit all the indicator strains; a high adhesion efficiency to the epithelial cells of chickens and also their resistance to a number of antibiotics, monensin, bile salts and pH 3.0. The inhibitory action was not affected by the addition of catalase and no inhibition was detected after neutralizing the supernatant culture fluid. The competitiveness of the most promising strains, Lact. salivarius CTC2183 and CTC2197, was assessed in chicken feed mixture and in vivo. It was concluded that both strains were capable of becoming predominant over the indigenous flora in the incubated chicken feed mixture. In vivo tests showed that Lact. salivarius CTC2197 was able to colonize and overcome Lact. salivarius CTC2183 and the indigenous flora in the crop and caecum of the inoculated chicks.     

Dynamics of the survival of enteropathogenic and saprotrophic bacteria passing through a birds’ digestive tract in their excrement and in water

The ability of saprotrophic bacterium Pseudomonas fluorescens 32 gfp and of two enteropathogenic bacteria Salmonella enterica var. Typhimurium MAE 110 gfp and Escherichia coli O157:H7 gfp to pass through the gastrointestinal tract (GIT) of birds (domestic chicken) and the survival dynamics of these bacteria in chicken excrement and after transmission to water have been detected. Chickens were fed with combined feed inoculated with the mentioned bacteria at a density of 107 cells/g of dry combined feed. The quantity of the surviving bacteria was assessed in chicken excrement that was subsequently used for inoculation of nonsterile and sterile pond water. Dynamics of labeled bacteria in water were also taken into consideration. Good survival rate of all investigated bacteria was demonstrated in all studied substrates. This fact points to the capability of bacterial transfer, even pathogenic for human, in nature through a number of substrates and niches during the cycle and of infection of these niches and substrates, even used as food by humans.     

Effects of two probiotic Lactobacillus strains on jejunal and cecal microbiota of broiler chicken under acute heat stress condition as revealed by molecular analysis of 16S rRNA genes

We examined the effects of probiotic Lactobacillus strains of Lactobacillus agilis JCM 1048 and Lactobacillus salivarius subsp. salicinius JCM 1230 on jejunal and cecal microbiota of broiler chicken under heat stress condition using terminal restriction fragment length polymorphism (T-RFLP) analysis. The jejunal bacterial community was limited to a few bacterial groups, mostly Lactobacillus spp. A relatively abundant and higher prevalence of Lactobacillus spp. were observed in the jejunal and cecal microbiota of the probiotic chickens compared with those of the control chickens under heat stress condition. In general, the probiotic strains did not significantly affect the abundance of L. agilis and L. salivarius in chicken intestine but clearly contributed to increasing their prevalence in the probiotic chickens. The probiotic Lactobacillus strains enriched the diversity of Lactobacillus flora in chicken jejunum and cecum by increasing the abundance and prevalence of Lactobacillus spp. inhabiting the intestine. The richness of Lactobacillus species tended to be similar among the jejunal and cecal microbiota. The bacterial community of cecum was complex and age-dependent. The major components of the cecal microbiota were clostridia and lactobacilli. The Clostridium subcluster XIVa was the most predominant group in chicken cecum. Probiotic Lactobacillus strains restored the microbial balance and maintained the natural stability of indigenous bacterial microbiota following heat stress-induced changes.     

Development of second generation merozoites of Leucocytozoon caulleryi in vitro

Sporozoites of Leucocytozoon caulleryi were inoculated into specific-pathogen-free (SPF) chickens intravenously. Fourteen days after inoculation, the infected blood, parasitized with second generation merozoites, was collected from the chickens. The blood was then suspended in SPF chicken serum or RPMI-1640 culture medium supplemented with 20% SPF chicken serum in petri dishes, which were cultured at 37 degrees C or 41 degrees C in a humidified atmosphere of 5% CO2. Second generation merozoites in parasitized, immature erythrocytes developed continuously through several substages and finally became micro- and macro-gametocytes after 6 days of incubation.