芽孢杆菌在动物肠道内的作用机制及其动物生产应用

芽孢杆菌属于革兰氏阳性菌,其主要特征是能够产生抗逆性的内生孢子——芽孢。芽孢能够抵抗多种不良环境,因此较易储存。与乳酸菌、酵母菌等微生态制剂不同,芽孢作为芽孢杆菌主要的商品形式,在动物肠道内的作用方式和机理较为复杂,目前已成为国内外研究的热点。文章对近几年芽孢杆菌在动物肠道中的作用机理及其养殖应用效果进行综述,并对其在养殖业中的应用前景进行了展望,以期为更好地开发和应用此类微生态制剂提供参考。     

枯草芽孢杆菌芽孢表面展示外源功能蛋白的应用

枯草芽孢杆菌是一种好氧的可直接用于人和动物的益生菌菌种,在不利条件下可以被诱导产生芽孢。芽孢具有特殊的构造及独特的生理特征,研究者们发现枯草芽孢杆菌芽孢是酶和免疫原等外源性功能蛋白的理想的锚定载体,以枯草芽孢杆菌芽孢衣壳蛋白作为分子载体,直接利用芽孢吸附作用和共价固定等方法使外源蛋白锚定在芽孢表面。目前已有多种酶蛋白、抗原蛋白和其他功能蛋白成功展示在枯草芽孢杆菌芽孢表面。本文主要对枯草芽孢杆菌芽孢结构及芽孢表面展示外源蛋白技术的策略和应用前景进行阐述。     

不同氧需求特性菌株在模拟肠道厌氧条件下的增殖

文章旨在研究丁酸梭菌、地衣芽孢杆菌和枯草芽孢杆菌3种典型的不同氧需求特性益生菌在模拟肠道条件下的增殖情况,为益生菌在动物生理条件下的应用提供试验依据。将冻存的丁酸梭菌、地衣芽孢杆菌和枯草芽孢杆菌活化后,初始菌数分别为104、106、106 cfu/ml,接种至相应的培养基中,维持pH值,置于厌氧培养箱中进行培养,每隔特定时间测定一次菌数,直至菌数不再变化时停止检测,作菌株生长曲线。试验结果表明:枯草芽孢杆菌维持在106数量级,几乎不能生长繁殖;地衣芽孢杆菌由106数量级增殖到108数量级,在培养20 h时接近增殖高峰;丁酸梭菌由104数量级迅速增殖到108数量级,在培养12 h时接近增殖高峰。由试验可以得出:丁酸梭菌更适合动物肠道厌氧环境,可在动物肠道迅速大量增殖代谢,最大限度发挥益生作用。     

枯草芽孢杆菌在畜禽养殖应用中的研究进展

枯草芽孢杆菌是畜禽养殖中常用的益生菌之一，在土壤及植物体表广泛存在，可形成芽孢，抗性好，并且在芽孢状态下具有良好的稳定性。枯草芽孢杆菌具有提高动物生长性能、稳定肠道菌群、提高免疫力及改善肉品质等作用。文章综述了枯草芽孢杆菌的生理特性、作用机制及其在常见动物生产中的应用研究进展，以期为饲用枯草芽孢杆菌的进一步开发和利用提供参考。     

饲用芽孢杆菌制剂在动物消化道中的作用机理

芽孢杆菌是动物肠道的正常菌群,是研制开发微生态制剂最主要的菌株之一。动物微生态制剂具有无毒、无副作用,促进动物生长,提高饲料转化率,替代抗生素等优点。但由于受制剂本身、动物机体、外界环境等多种因素的影响,其应用效果的重复性和稳定性较差。本文就芽孢杆菌制剂在动物肠道中的作用机理作一阐述。     

纳豆芽孢杆菌与黄芪多糖在动物生产中应用的研究进展

纳豆芽孢杆菌属细菌科芽孢杆菌属,作为益生菌的一种,可用于医药、食品和饲料;黄芪多糖是从豆科植物膜荚黄芪或蒙古黄芪根中分离出的多糖组分,是一种重要的天然成分,由葡萄糖、半乳糖、阿拉伯糖等组成;大量研究结果表明,纳豆芽孢杆菌和黄芪多糖都具有提高动物免疫力、改善动物生产性能和促进饲喂效果的作用。作者查阅了大量国内外相关文献,就纳豆芽孢杆菌及黄芪多糖在动物生产中的应用进行综述,并对二者在动物生产中混合使用的前景进行展望。     

6株猪源芽孢杆菌的分离鉴定及其益生性研究

本研究旨在通过高温处理和常规厌氧菌分离法从健康肥猪粪便中分离芽孢杆菌,并通过培养性状、生化试验、PCR、肠道耐受、抗菌活性和接种试验动物等方法鉴定筛选性状稳定、优良的益生性芽孢杆菌。结果显示,共分离到6株芽孢杆菌,其中1株巨大芽孢杆菌、1株死谷芽孢杆菌、2株解淀粉芽孢杆菌和2株枯草芽孢杆菌;分离菌对多黏菌素和青霉素耐药性较强,对其他12种常用药物较敏感,对致病性大肠杆菌和金黄色葡萄球菌的抑菌效果较好;4种芽孢杆菌均可在酸性、高胆盐和高温条件下生存,特别是巨大芽孢杆菌和枯草芽孢杆菌耐受能力较强;分离的芽孢杆菌对小鼠均无致病性,其中巨大芽孢杆菌和死谷芽孢杆菌有较明显的促进试验动物生长的作用。结果提示,巨大芽孢杆菌和死谷芽孢杆菌可作为益生性芽孢杆菌的初步选择。     

纳豆芽孢杆菌在貉饲养中的应用试验

纳豆芽孢杆菌(Bacillus natto)属细菌科、芽孢杆菌属,是枯草芽孢杆菌的一个亚种,1999年6月份,被我国农业部认证为可直接饲喂动物的饲料级微生物添加剂。纳豆芽孢杆菌是需氧菌中的非致病菌,对动物和环境安全,具有调节动物肠功能的效果,可以提高动物的抗病能力,促进生长。貉是我国北方地区皮毛特种养殖的主要动物品种之一,在东北三省、华北地区均有大量养殖。因为貉饲养周期短,小貉断乳分窝后的饲喂和生长是关键时期,往往关系到最后的体长和毛质,而这时华北地区6~8月份天气炎热,饲养环境大多为简单遮盖笼养,小貉的热应激反应强烈,并且饲喂鱼…     

枯草芽孢杆菌的生理功能及其在动物生产中的应用

枯草芽孢杆菌作为一种无毒、无残留、无耐药性的绿色饲料添加剂,其具有提高饲料转化率、增大饲料营养价值、增强动物机体免疫力、抵抗疾病、改善动物肠道健康等作用,因此,本文对枯草芽孢杆菌的生物学特性、生理功能以及在动物生产上的应用研究进展进行综述,以期对枯草芽孢杆菌的进一步研究和探索提供一定的参考。     

饲用微生物添加剂的使用效果

饲用微生物添加剂是一类无毒、无副作用、无毒性残留的新型饲料添加剂。目前用于制造饲用微生物添加剂的主要菌种按使用微生物种类将其分为以下几种：①芽孢杆菌制剂，此类菌属在动物肠道中零星存在，由于其能形成芽孢，故具有耐高温、耐干燥、耐制粒过程、耐消化道环境的优点。目前最常用的有枯草芽孢杆菌和地衣芽孢杆菌；②乳酸菌制剂，此类菌属是动物肠道中的正常微生物，能够分解糖类。     

不同方法对牛舍气载魏氏梭菌型别的研究

分别采用ELISA、多重PCR方法对从一个犊牛舍分离到的魏氏梭菌进行型别研究,结果显示:ELISA检测结果为88%的菌种属于A型,3.4%为C型,8.6%是D型;而多重PCR结果均为A型。     

Relationship between the concentration of different bioaerosol components and the general hygienic condition in two pig fattening houses

In the study presented here the relationship between the hygienic condition and the concentration of different air contaminants in two pig fattening houses was investigated. Deficiencies in routine cleaning, which were characterized by an increased soiling of animals and stable surfaces with faeces, led to increased concentrations of airborne dust, airborne endotoxins as well as increased numbers of total airborne bacteria and airborne gram-negative bacteria. However these deficiencies were not reflected by the concentration of airborne Clostridium perfringens which were earlier postulated as an indicator of faecal pollution in the air of cattle barns. Furthermore the results of this study were used to discuss advantages and disadvantages of impingement and impaction for the sampling of airborne microorganisms in animal houses.     

ELISA对动物舍气载魏氏梭菌型别的研究

采用ELISA方法对从一个犊牛舍空气中分离到的魏氏梭菌进行型别的鉴定。结果显示：88％的菌种属于A型，3.4％为C型，8.6％是D型，B型未能确认。     

Isolation and characterization of Clostridium perfringens from apparently healthy animals of the Shandong province of China

In a pilot study the presence and frequency of Clostridium (C.) perfringens was investigated among apparently healthy farm animals in the Shandong province of China. 748 faecal samples were collected from 9 pig-, 4 sheep-, 7 cattle- and 5 rabbit farms. C. perfringens was isolated from 124 samples (16.6%). The isolates were classified into major toxin types by using PCR analysis detecting the genes encoding these toxins. All isolates were identified as C perfringens toxin type A. There are also some reports from different regions in China linking C. perfringens toxin type A strains to gastrointestinal diseases. Therefore further investigations about the epidemiologic role of C perfringens toxin type A strains in the Shandong region are necessary. Currently, cases of enterotoxemia from this region are investigated for the presence of C perfringens.     

Population-based study of fecal shedding of Clostridium perfringens in broodmares and foals

OBJECTIVE: To determine the percentage of broodmares and foals that shed Clostridium perfringens in their feces and classify the genotypes of those isolates. DESIGN: Prospective cross-sectional study. ANIMALS: 128 broodmares and their foals on 6 equine premises. PROCEDURES: Anaerobic and aerobic bacteriologic cultures were performed on feces collected 3 times from broodmares and foals. All isolates of C. perfringens were genotyped. RESULTS: Clostridium perfringens was isolated from the feces of 90% of 3-day-old foals and 64% of foals at 8 to 12 hours of age. A lower percentage of broodmares and 1- to 2-month-old foals shed C. perfringens in their feces, compared with neonatal foals. Among samples with positive results, C. perfringens type A was the most common genotype identified (85%); C. perfringens type A with the beta2 toxin gene was identified in 12% of samples, C. perfringens type A with the enterotoxin gene was identified in 2.1% of samples, and C. perfringens type C was identified in < 1% of samples. CONCLUSIONS AND CLINICAL RELEVANCE: Clostridium perfringens was identified from the feces of all but 6 foals by 3 days of age and is likely part of the normal microflora of neonatal foals. Most isolates from broodmares and foals are C. perfringens type A; thus, the clinical relevance of culture results alone is questionable. Clostridium perfringens type C, which has been associated with neonatal enterocolitis, is rarely found in the feces of horses.     

The influence of selected tannin-containing plant species on the tenacity of pathogenic bacteria in an in-vitro rumen system. 1. Communication: the influence of selected plant species on the tenacity of Cl. perfringens

The effect of plant species containing tannins on the tenacity of Cl. perfringens was elucidated. Trials were purchased in physiological saline solution and in a rumen-fluid-medium under anaerobic conditions. The results obtained show, that within minutes the tenacity of Cl. perfringens can be reduced by some of the tested plant material not only in physiological saline solution but also in a rumen-fluid-medium. The results indicate that the reaction of some vegetable tannins and Clostridium perfringens germs is a specific one and could be used in controlling diseases caused by Clostridium perfringens.     

Effect of Eimeria tenella infection on the caecal population of lincomycin-resistant Clostridium perfringens introduced into chickens

The effect of Eimeria tenella infection on the caecal population of lincomycin-resistant Clostridium perfringens (KGW 851) newly introduced into chickens was studied. Four groups of chickens consisted of: (1) Uninoculated controls; (2) inoculated with C perfringens (KGW 851); (3) inoculated with E tenella; and (4) inoculated with C perfringens (KGW 851) followed by E tenella. Five chickens in each group were necropsied on each of days 0, 3, 5, 7, 10 and 14 after the E tenella inoculation. The mean total C perfringens counts in the caecal contents increased at five days after E tenella inoculation and reached maximum counts at seven days after the inoculation. Also lincomycin-resistant C perfringens readily established itself at approximately one 10th of the total C perfringens population in the presence or absence of E tenella infection.     

Influence of bacteria on Clostridium perfringens infections in young chickens

When monoflora chickens with Lactobacillus acidophilus or Streptococcus faecalis were inoculated with Clostridium perfringens either in broth culture or resuspended in Gifu anaerobic medium broth or supernatant fluid, few or no chickens died. Approximately 50% of germ-free chickens died after inoculation of C. perfringens culture, whereas no conventional birds died after inoculation of broth culture. C. perfringens in the contents of duodenum from germ-free chickens numbered about 10(4) colony-forming units (CFU)/g after inoculation 10(8) CFU broth culture per bird, but in gnotobiotic and conventional chickens this organism decreased or was not detected. When C. perfringens was cultured in intestinal contents collected from germ-free chickens, C. perfringens proliferated but alpha toxin was not detected. These findings indicate that the pathogenicity of C. perfringens was suppressed by L. acidophilus or S. faecalis administered previously or inhibited by normal intestinal flora.     

产气荚膜梭菌对养牛业的危害及其防制

近年来产气荚膜梭菌对中国养牛业的危害巨大,其流行型别和致病特点较以往也在发生变化,其中C、D型菌对牛致病增多;部分病例呈现慢性型发病症状。作者参考了大量文献对牛产气荚膜梭菌病的流行病学、发病原因、临床症状、病理变化、诊断方法及防制措施进行了综述。     

Survival of clostridium perfringens during simulated transport and stability of some plasmid-borne toxin genes under aerobic conditions

Clostridium perfringens is a pathogen of great concern in veterinary medicine, because it causes enteric diseases and different types of toxaemias in domesticated animals. It is important that bacteria in tissue samples, which have been collected in the field, survive and for the classification of C. perfringens into the correct toxin group, it is crucial that plasmid-borne genes are not lost during transportation or in the diagnostic laboratory. The objectives of this study were to investigate the survival of C. perfringens in a simulated transport of field samples and to determine the stability of the plasmid-borne toxin genes cpb1 and etx after storage at room temperature and at 4 degrees C. Stability of the plasmid-borne genes cpb1 and etx of C. perfringens CCUG 2035, and cpb2 from C. perfringens CIP 106526, JF 2255 and 6 field isolates in aerobic atmosphere was also studied. Survival of C. perfringens was similar in all experiments. The cpbl and etx genes were detected in all isolates from samples stored either at room temperature or at 4 degrees C for 24-44 h. Repeated aerobic treatment of C. perfringens CCUG 2035 and CIP 106526 did not result in the loss of the plasmid-borne genes cpb1, cpb2 or etx. Plasmid-borne genes in C. perfringens were found to be more stable than generally reported. Therefore, C. perfringens toxinotyping by PCR can be performed reliably, as the risk of plasmid loss seems to be a minor problem.