鸡肠道正常菌群的研究进展

正常菌群作为宿主的组成部分,参与了动物体的生长、发育、消化、吸收、营养、免疫、生物拮抗及其各种功能和结构的发生、发展和衰退的全过程。动物与菌群保持动态的微生态平衡,在某些因素作用下,正常菌群会发生变化。当有益菌占优势时,动物就会向健康的方向发展,而有害菌占优势时,最终会引起宿主的病变反应。鸡肠道菌群种类多,数量大,多为厌氧菌,研究其肠道正常菌群的结构及其演替规律,有着极其重要的意义,可为开发功能微生物、丰富菌质资源以及研制禽微生态制剂提供理论基础。     

双歧杆菌黏附的研究进展

双歧杆菌是人体肠道正常菌群中的优势菌种 ,黏附和定植于肠黏膜上皮细胞后 ,对宿主发挥生物屏障、营养、免疫、抗肿瘤、抗衰老等生理作用。黏附 (ａｄｈｅｓｉｏｎ)是指微生物与宿主上皮细胞通过生物化学作用特异性地连接在一起。由于黏附是微生物与微生物、微生物与宿主相互关系的先决条件之一 ,是定植的第一步。因此 ,有关双歧杆菌黏附的研究越来越受到人们的重视。本文现就这一方面的研究进展作一综述。1　双歧杆菌对肠上皮细胞黏附的特点　　双歧杆菌进入肠道后能否黏附于宿主肠道黏膜上皮细胞表面 ,形成稳定的菌群 ,是关系到其是否能发…     

嗜酸乳杆菌黏附鸡胚肠黏膜上皮细胞能力的研究

目的建立肠黏膜上皮细胞模型和测定嗜酸乳杆菌的黏附能力。方法将嗜酸乳杆菌用胃蛋白酶和HCl-H2O低pH以及反复冻融、灭活等方法处理后测定其黏附能力。结果成功地建立了鸡胚肠黏膜上皮细胞模型;经胃蛋白酶和HCl-H2O低pH以及灭活处理后,嗜酸乳杆菌的黏附能力和对照组差异有显著性。反复冻融后的嗜酸乳杆菌黏附能力与对照组差异无显著性。结论胃蛋白酶和HCl-H2O pH2.0会使嗜酸乳杆菌黏附肠黏膜上皮细胞能力下降,热灭活可使嗜酸乳杆菌的黏附能力提高,反复冻融对嗜酸乳杆菌的黏附能力无明显影响。     

益生菌地衣芽孢杆菌治疗鸡腹泻机理初探

目的：探讨益生菌地衣芽孢杆菌饲喂鸡腹泻的治疗效果以及分子机理。方法：从养鸡场土壤中选择性分离芽孢杆菌,通过优 化条件提高产生芽孢的比例;利用芽孢和大米混合后饲喂腹泻鸡,通过克隆测序分析腹泻鸡肠道微生物群落在饲喂前后的差异。 结果：我们分离到一株地衣芽孢杆菌,通过优化条件使产芽孢的比例提高到60 %。利用芽孢饲喂一周后能够有效地治疗鸡腹泻。 分析鸡肠道微生物群落发现：鸡腹泻后其肠道细菌群落的多样性和均匀度降低。造成腹泻鸡肠道主要菌群为动胶杆菌（Zoogloea sp.）;经芽孢饲喂后,主要菌群转变为拟杆菌（Bacteroides sp.）,与健康鸡的肠道微生物主要菌群相似。结论：我们筛选到一株可能 治疗鸡腹泻的芽孢杆菌,通过优化培养条件能够提高其产芽孢比例;腹泻鸡经芽孢饲喂后,其肠道中致病菌被益生菌所代替,形 成正常的肠微生物菌群而恢复健康。     

鸡肠道微生物菌群的建立发育、分布和生理学意义

鸡的胃肠道具有复杂的微生物菌群,该微生物菌群与宿主的肠道和整体健康密切相关,为了全面揭示鸡肠道微生物菌群的组成及其功能,本文对鸡肠道微生物菌群的建立发育、各肠段群落的分布及其生理学意义进行综述,从而为鸡肠道功能菌株的分离及有效利用,合理调控微生物菌群-宿主相互作用,提高饲料转化率和改善肠道健康提供理论依据。     

结直肠癌患者肠道黏膜菌群多样性变化研究

目的应用PCR-DGGE技术对结直肠癌患者肠道黏膜局部菌群多样性进行研究,为结直肠病变的防治提供微生态调节思路。方法收集正常对照组、结直肠息肉组及结直肠癌组患者各30例,采集结直肠黏膜局部肛拭子,提取细菌基因组DNA,采用PCR-DGGE对肠道黏膜局部菌群进行指纹图谱分析。结果正常对照组、结直肠息肉组和结直肠癌组患者PCR-DGGE指纹图谱分析显示3组肠道黏膜局部菌群多样性发生了显著的变化,3组肠道黏膜局部菌群发生了显著的菌群变迁。结论 PCR-DGGE分析结直肠癌患者肠道黏膜局部菌群多样性变化对监测肠道局部微生态变化在结直肠癌的发生过程中的作用具有重要价值。     

宽体金线蛭消化道的组织学观察

运用解剖学和组织学方法对宽体金线蛭消化道的结构进行了组织学研究。结果表明,宽体金线蛭的嗉囊向两侧伸出11对侧盲囊,第6对侧盲囊狭长并延伸到直肠两侧;咽主要由黏膜层、肌层和外膜构成,外膜几乎不可见;食道、嗉囊、肠和直肠管壁由黏膜层、黏膜下层、肌层和浆膜构成;咽和直肠的上皮具纹状缘。除肠外,其他消化道的上皮细胞均无发达的纤毛,且黏膜上皮皆为单层柱状上皮;除肠和直肠外,腺体及导管较少;直肠的黏膜肌层为内环外纵两层,其他各部均为纵行肌一层;消化道各部黏膜下层较发达;外膜为浆膜,与黏膜下层分界不明显。     

T-RFLP技术检测结直肠癌患者肠道黏膜相关菌群改变

目的研究结直肠癌患者肠道黏膜相关菌群组成差异,探索肠道菌群在结直肠癌发生发展中的作用。方法用末端限制片段长度多态性(Terminal restriction fragment length polymorphism,T-RFLP)技术分析50例结直肠癌患者癌组织、癌旁正常黏膜与健康对照组肠道黏膜相关细菌组成差异。结果与健康对照组相比,结直肠癌患者肠道黏膜相关细菌丰度显著增加(P0.05),多样性显著降低(P0.05)。结直肠癌患者癌组织与癌旁正常黏膜的黏膜相关细菌组成相近,但与健康对照组存在显著差异。MspI酶切的160bp、560bp的T-RF片段在结直肠癌患者癌组织及癌旁正常黏膜中为优势片段,而在健康对照组中缺失。相反,MspI酶切的66bp、74bp、141bp的T-RF片段在健康对照组为优势片段,但在结直肠癌癌组织及癌旁正常黏膜中缺失。结论肠道菌群失调与结直肠癌的发生发展密切相关。MspI酶切的66bp、74bp、141bp、160bp、560bp的T-RF片段所代表的细菌可能在结直肠癌的发生发展中起重要作用。     

鸡肠道菌群和短链脂肪酸相互关系的研究进展

肠道是动物机体重要的消化和营养吸收器官。肠道菌群决定肠道健康,进而影响机体健康。近年来关于肠道菌群的研究越来越多,且肠道菌群酵解底物产生的短链脂肪酸也备受人们关注。短链脂肪酸主要包括乙酸、丙酸、丁酸等及其盐类。在对肠道功效方面,短链脂肪酸发挥着重要作用,如氧化供能、维持水电解质平衡、调节免疫、抗病原微生物及抗炎、调节肠道菌群平衡、改善肠道功能等。因此,本文根据近年来国内外相关研究报道,综述了鸡肠道不同种类、含量的菌群对短链脂肪酸来源和吸收的影响;不同种类、含量和制剂形态的短链脂肪酸对肠道菌群影响的研究进展,为更好地了解鸡肠道菌群和短链脂肪酸的相互关系和提高禽类养殖水平提供理论指导。     

鸡白痢生物竞争性免疫的研究

为了有效地控制鸡白痢病对养鸡业的危害,根据生物竞争性排斥的原理,从健康鸡盲肠内容物中分离到肠道正常厌氧菌群,首次在国内研制成鸡白痢生物竞争性菌苗。三年内(1986～1988年)共试制菌苗146.8万羽份。室内试验,用沙门氏杆菌标准强毒攻击结果,免疫组雏鸡保护率为89.2％,土霉素对照组雏鸡保护率为90％,空白对照组雏鸡保护率为0％;经6个省、市扩大试验,免疫雏鸡在15日龄内平均存活率为95.2％;饲喂土霉素组雏鸡平     

Lactic bacteria in the digestive tract of poultry

Lactic bacteria predominate in the microflora of the digestive tract of chicken and turkey. They are represented mainly by Lactobacillus acidophilus, L. salivarius, L. fermentum and L. buchneri. Streptococcus faecium is always isolated. L. ruminis, L. vitulinus, L. delbrueckii, L. coryniformis and L. viridescens were found in this ecological niche for the first time. S. faecium and S. faecalis prevail in the digestive tract of geese and ducks, while lactobacilli are detected in a lesser amount and are represented mainly by L. plantarum. L. salivarius cells isolated from the digestive tract of poultry are highly polymorphous. Most of the lactic acid bacteria found in the digestive tract of poultry can grow at 45-50 degrees C whatever is the species they belong to.     

中华绒螯蟹消化道组织学及扫描电镜研究

对中华绒螯蟹成蟹消化道各段进行了光镜组织学结构的观察;应用扫描电镜技术,观察了中华绒螯蟹消化道各段黏膜上皮表面超微结构特征。结果表明：除中肠及后盲囊外,整个消化道黏膜上皮表面均有较厚的分泌物层和较发达的纤毛层。纤毛形态结构各异;以食道和后肠分布最密,胃和肠球次之。消化道各段黏膜上皮细胞表面均形成大小不一、形态各异的多级皱褶和嵴。仅中肠表面具典型微绒毛结构。各消化道段黏膜上皮表面均未见杯状细胞,上皮下基膜发达,黏膜下层明显,消化腺分布其间。整个消化道壁的肌层均为横纹肌,且排列疏松,外膜多为浆膜。     

Effect of polymyxin M on intestinal microorganisms of gnotobiotic chicks]

The effect of polymyxin M on the microflora artifically introduced into the digestive tract of gnotobiotic chickens was studied. It was found that polymyxin M caused dysbacteriosis in the digestive tract. Reduction of the impaired biocenosis after discontinuation of polymyxin use was rapid and practically complete.     

Effect of the lavage of the digestive tract on microflora in patients with polyps in the large intestine

The microbial status of the intestine and the influence of lavage with polyethylene glycol and balanced electrolyte solution (PEG + E), used in the process of the preparation of patients to polypectomy, on this status were evaluated. The study of microflora was made before oral lavage after, and 48-72 hours later its completion. For control, a group of healthy volunteers, also subjected to oral lavage with PEG + E, was used. The lavage of the digestive tract with PEG + E led to a sharp change in the microbial status in both groups. Some microorganisms, previously absent in the intestine, were found after lavage. The processes of the restoration of intestinal microflora after lavage in healthy volunteers and in patients with polyps had certain differences. In healthy volunteers intestinal microflora was completely restored, and even improved, 48-72 hours after lavage with PEG + E, while at the expiration of this time intestinal microflora in the patients with polyps could be characterized as dysbiotic.     

Diversity of insect intestinal microflora

The influence of geographic location, season, age, and part of the digestive tract on bacterial diversity was evaluated on intestinal microflora of honeybees, wasps, and cockroaches using DGGE analysis. PCR-DGGE analyses with universal bacterial primers targeting 200-bp region of the 16S rDNA gene afforded the profile of complex bacterial DNA; specific primers were used to determine the profile of bifidobacteria whose concentration in digestive tract was determined by real-time PCR. Selected PCR products were identified by sequencing. The microflora of the bees exhibited little variations among the hives from distant locations. Their bifidobacterial population formed 2.8-8.4 % of total bacteria and was very homogeneous. The total gut microflora of wasps was also homogeneous, only two samples being affected by the season or the location; on the other hand, wasp bifidobacterial population was very heterogeneous. Cockroaches showed the highest variations in microflora composition, the age and diet being the ultimate factors; bifidobacteria counts also varied among tested individuals (0.1-34.1 % of total bacteria). Our results suggest that nutrition habits are the strongest factor affecting the insect microflora, giving higher variations to omnivorous species.     

What is currently known about the molecular mechanisms of colonisation resistance

Anaerobes are the main bacteria which inhabit the digestive tract. They have adapted their development to many environmental factors such as host secretions, corresponding to control mechanisms which allow a relative stability of microflora in healthy humans. These control mechanisms include the control of endogenous and exogenous bacterial populations which corresponds to bacterial antagonism occurring in the digestive tract of mammals and represents one of its main functions. The main antagonism to study is colonisation resistance since this function of the gut microflora is responsible for the prevention of many intestinal diseases. However, only a few things are currently known about this function and the main questions which need attention are: (1) which bacteria are responsible for colonisation resistance? and (2) what are the molecular mechanisms involved in such a function? In order to answer these questions, we need to study simplified models based on gnotobiotic animals. Two models are currently being studied in France. One corresponds to the colonisation resistance of C. perfringens which seems to be linked to the in vivo secretions of an antimicrobial substance by a Ruminococcus species. The other corresponds to the colonisation resistance of C. difficile whose mechanisms are different and seem to be linked to an interaction between mucin and microflora.     

Colicinogenic activity of intestinal microflora as a sign of dysbacteriosis of the gastrointestinal tract

Clinical and bacteriological studies have revealed that the production of colicin by Escherichia coli forming a part of intestinal microbiocenosis is related to the clinical manifestations of inflammatory diseases of the gastrointestinal tract. During the exacerbation of chronic inflammatory processes of the digestive system the proportion of colicin producing E. coli increases (more than 45%) in comparison with that of E. coli fecal strains isolated in children and adolescents regarded as healthy (less than 15%). The possibility of using the colicin producing activity of intestinal microflora for the evaluation of the dysbiotic states of gastrointestinal tract is discussed.     

亚东鲑消化系统的形态学和组织学观察

亚东鲑消化系统包括消化道和消化腺。消化道分为明显的食道、胃和肠等。食道粘膜为复层上皮,其中含有杯状细胞和味蕾,胃、肠粘膜为单层柱状上皮,其中散布较多的杯状细胞。消化腺包括肝脏和胰腺,肝小叶分界明显,胰腺外分泌部由腺泡组成,内分泌部即胰岛分散存在于外分泌部之间。     

Metagenomic bacterial community profiles of chicken embryo gastrointestinal tract by using T-RFLP analysis

Thirty microbial phylotypes of microorganisms were found in the gastrointestinal tract of chicken belonging to the Hajseks White breed, and 38 phylotypes were found in the gastrointestinal tract of chicken belonging to the Hajseks Brown breed. The microbiome of the gastrointestinal tract of the chicken embryos of the Hajseks White breed was dominated by the typical representatives of avian intestinal microflora—bacteria of the family Enterobacteriaceae (47.3%), orders Actinomycetales (13.6%) and Bifidobacteriales (20.6%), and the family Lachnospiraceae (1.1%). The microbiome of the gastrointestinal tract of the chicken embryos of the Hajseks Brown breed was dominated by the pathogenic bacteria of the order Rickettsiales (94.8%). The metagenome of gastrointestinal tract of both breeds also contained a small number of genes of unidentified bacteria.     

Comparison of digestive microflora between feedlot cattle with and without infection by<Emphasis Type="Italic">Cryptosporidium andersoni</Emphasis>

The influence of cryptosporidial abomasitis on digestive anaerobic microflora in feedlot cattle with spontaneous Cryptosporidium andersoni colonization of abomasum was shown. Significant differences were found after the cultivation of abomasal content. Scopulariopsis brevicaulis was detected in damaged areas of infected abomasum. PCR analysis of ruminal fluid showed no differences between the two animal groups regarding qualitative composition of anaerobic and facultative anaerobic rumen microflora. The concentration of volatile fatty acids (acetate, propionate, butyrate) and ammonia in the rumen content showed that examined metabolic parameters were within normal limits except for ammonia content, which was higher in infected (291 mg/kg) than in healthy animals (203 mg/kg).