Pulmonary Clearance of Bacillus subtilis Spores in Pigs

The pulmonary clearance rate of Bacillus subtilis was determined in ten pigs (23-39 kg) exposed simultaneously for 15 minutes to an aerosol generated by an ultrasonic nebulizer. Two pigs were killed at each interval of zero, two, four, eight and 12 hours and the concentrations of B. subtilis in lungs (all lobes), dorsal and ventral nasal turbinates, trachea, pharyngeal and bronchial lymph nodes were determined. The mean percent (± standard error) pulmonary clearance of B.subtilis was 54.2±11.7, 53.0±11.8, 77.4±5.2 and 88.1±3.7 at two, four, eight and 12 hours, respectively. The numbers of B. subtilis retained in the posterior (caudal and accessory) lobes at zero time were significantly greater than those in the anterior (cranial and middle) lobes (P<0.05). However, by 12 hours postinoculation the numbers of organisms retained in the two regions did not differ significantly (P>0.05). The mean percentage of B. subtilis retained by the turbinates, trachea, pharyngeal and bronchial lymph nodes varied between pigs at each time interval, but was usually less than that retained by the lungs.

It was concluded that deposition of B. subtilis spores took place in all parts of the respiratory tract when pigs were exposed to aerosols and that the spores were progressively cleared by the normal lung.

     

Characterization of Pasteurella Hemolytica Isolated from the Respiratory Tract of Cattle

Morphological, cultural, biochemical, and serological characteristics of 43 strains of Pasteurella hemolytica isolated from the respiratory tract of cattle, including 37 that had shipping fever, were determined. With one exception, all strains satisfied the major criteria for differentiation of the species from P. multocida — hemolysis on blood agar, absence of indole production, and growth on MacConkey's agar. Many strain variations in fermentative capacity were noted, although other biochemical characteristics were relatively constant. The ability of a strain to ferment carbohydrates often depended upon the medium in which the test was conducted. All strains studied were identified as type A strains on the basis of colonial morphology, biochemical, and growth characteristics, and sensitivity to penicillin. When grouped on the basis of serological reactions, 38 strains were type 1, three were type 2, one was type 11, and one was untypable; 34 of the shipping fever strains were 1 and three were type 2.     

Influence of Immunization Procedures on Upper Respiratory Tract Immunity in Cattle

Aspects of respiratory tract immunity have been investigated in the bovine species. Using Past. hemolytica type I as the antigen for this model the relationship of nasal and serum antibody production to the route of vaccination and type of vaccine was investigated in a series of 15 dairy calves from two to four months of age. Experimental results indicated that an aerosol vaccination with live Past. hemolytica resulted in a significant nasal antibody response while parenterally vaccinated gave calves with equivalent serum titers had no significant nasal antibody response.     

黄牛呼吸道CD3+淋巴细胞分布的研究

CD3⁺是T细胞群的重要表面标志,呼吸道黏膜下分布的CD3⁺淋巴细胞作为抗感染黏膜免疫的基础,在保护机体抵抗呼吸道感染中发挥重要作用。为了解黄牛呼吸道CD3⁺淋巴细胞和淋巴组织的分布,本研究运用HE染色法和免疫组织学方法对5头7岁健康婆罗门黄牛的鼻黏膜、气管、肺内支气管及肺脏组织的CD3⁺淋巴细胞和淋巴组织的分布进行了研究。结果显示,黄牛的鼻黏膜、气管、肺内支气管和肺脏组织中均分布有CD3⁺淋巴细胞,且主要分布于黏膜上皮间及其下方固有层中及腺体周围;在鼻黏膜和肺脏组织中分布有CD3⁺淋巴细胞形成的弥散淋巴组织。牛呼吸道中CD3⁺淋巴细胞数量在鼻黏膜和肺脏组织中分布最多,气管黏膜、肺内支气管黏膜次之。本试验结果明确了CD3⁺淋巴细胞在黄牛呼吸道中的分布谱,表明黄牛呼吸道具备引发局部黏膜免疫的基础条件,为牛呼吸道黏膜免疫及呼吸道疾病防治研究提供了数据支撑。     

重庆地区肉牛呼吸道疾病的发病原因及综合防治措施

近年来,重庆地区大批肉牛暴发呼吸道疾病,由于病因分析不清、防治措施不当,造成患牛死亡率不断上升。结合重庆地区养牛实际情况,详细阐述了肉牛呼吸道疾病的发病原因,提出了控制该病的综合防治措施,以期为广大养殖工作者提供有益参考。     

日粮中添加纳豆枯草芽孢杆菌对犊牛消化道发育的影响

本试验旨在研究纳豆枯草芽孢杆菌对犊牛断奶早期和断奶后8周消化道生长发育的影响。选取24头7日龄中国荷斯坦奶牛公犊,随机分为3个处理,每个处理8头犊牛,试验1、2组犊牛分别饲喂Na型和N1型纳豆枯草芽孢杆菌菌液,对照组不饲喂菌液。饲喂的牛奶中添加纳豆枯草芽孢杆菌菌液,连续饲喂直到开食料采食量达到规定要求时断奶;断奶时各组随机选取4头犊牛屠宰,余下4头犊牛继续饲养,8周后屠宰,称胴体重。结果表明,试验1组犊牛断奶早期瘤网胃重量明显高于对照组(P0.05);试验2组犊牛断奶早期及断奶后8周瘤胃pH显著低于对照组(P0.05),且与对照组相比,断奶早期皱胃pH显著下降(P0.05);试验1组犊牛断奶早期及断奶后8周十二指肠长度较对照组相比明显缩短;断奶后8周两处理组犊牛回肠长度显著小于对照组(P0.05);此外,饲喂纳豆枯草芽孢杆菌还可显著降低犊牛十二指肠和空肠前段食糜的pH(P0.05)。本试验结果表明,饲喂纳豆枯草芽孢杆菌有利于营养物质消化,促进犊牛生长。     

水貂肠道枯草芽孢杆菌的分离及16S rRNA鉴定

为了获得水貂的有益菌种,及研制毛皮动物益生菌制剂提供基础,并为进一步深入研究枯草芽孢杆菌提供参考,从健康水貂的肠道中分离纯化出1株枯草芽孢杆菌,编号为 P2,通过形态学观察、生理生化试验以及16S rRNA 序列分析及同源性比较进行综合鉴定,结果显示菌株 P2与菌株 Bacillus subtilis CICC 10023（GU980947.1）亲缘关系最近,同源性达到了99.9%,因此鉴定 P2菌株为枯草芽孢杆菌。     

Influence of Dietary Bacillus subtilis C-3102 Spores on Live Performance of Broiler Chickens in Four Controlled Pen Trials

Four trials were conducted to evaluate Bacillus subtilis spores as a direct-fed microbial for improving broiler performance. In trials 1 to 3, straight-run Cobb 500 broiler chicks were grown to 42, 42, and 39 d, respectively, to evaluate diets containing Calsporin (0.05%; contributing spores at 0.003% level), an alternative growth promoter, compared with control basal diets. The additive significantly increased BW in all experiments (average +0.113 lb or +2.90%) and decreased feed conversion ratio in 2/3 trials (average 3 trials −0.027 lb of feed/lb of body weight or −1.46%) without affecting mortality. In trial 4, on new litter with a used litter covering and relatively high stocking density (0.67 ft²/bird or 0.0622 m²/bird), Ross × Hubbard HiY equal mixed-sex chicks were grown to 49 d of age. On all sides of pens, 34 in. high corrugated paper was used to prevent crossover of test additive but provided minimal ventilation and caused wet litter. Chick quality was substandard due to omphalitis. Bacillus subtilis spores (0.003%) treatment gave best BW and feed conversion results (+0.446 lb or +8.66% and −0.146 lb of feed/lb of body weight or −6.92%) compared with control treatment though not significantly better than bacitracin-methylene disalicylate (BMD) (55 ppm) or Bacillus subtilis spores plus BMD. Mortality was significantly lowerin control than the combined additive treatment (in which no culling and large differences in growth increased mortality of weaker chickens). Bacillus subtilis spores improved broiler chicken BW and feed conversion ratio and in a direct comparison successfully replaced BMD.     

饲粮添加凝结芽孢杆菌与枯草芽孢杆菌对断奶仔猪生长性能的影响

将32头28日龄断奶(杜×长×大)健康仔猪平均分成4个处理组:对照组(组合抗生素组)、试验组1(凝结芽孢杆菌组)、试验组2(枯草芽孢杆菌组)、试验组3(同时添加凝结芽孢杆菌及枯草芽孢杆菌组),研究凝结芽孢杆菌与枯草芽孢杆菌组合使用,对28~56 d断奶仔猪生长性能的影响。试验结果显示:平均日增重指标:试验组1和试验组3差异不显著(P0.05),均显著高于(P0.05)对照组和试验组2。料肉比指标,试验组1显著低于(P0.05)其他三个处理组。试验组1仔猪对饲料的干物质表观消化率与对照组差异不显著(P0.05),均高于(P0.05)试验组2。试验结果表明:仔猪商业饲料在组合使用多种常规饲用抗生素的基础上,单一添加饲用凝结芽孢杆菌能够进一步改善断奶仔猪的生产性能;然而,单一添加枯草芽孢杆菌、或凝结芽孢杆菌与枯草芽孢杆菌组合使用,均没有获得进一步改善仔猪生长性能的显著正效应。     

Isolation and Characterization of a Virus from the Reproductive Tract of Cattle

From biopsies taken from the vaginal tract of dairy cattle a virus was isolated in embryonated eggs. This virus was cytopathogenic to chick kidney and bovine embryo cell cultures with the formation of plaques on the former. Antisera for Infectious Pustular Vulvovaginitis, Enteric Cytopathogenic Bovine Orphan, Chick Embryo Lethal Orphan, Newcastle disease, Infectious Bronchitis, and Laryngotracheitis failed to neutralize the virus.     

头孢喹肟在猪呼吸道感染中应用的研究进展

呼吸道疾病严重威胁畜禽养殖业的发展,导致动物生长缓慢,使发病率和死亡率大幅升高,造成巨大的经济损失。胸膜肺炎放线杆菌、多杀性巴氏杆菌、链球菌、副猪嗜血杆菌等是诱发猪呼吸道感染的常见病原菌。头孢喹肟为第4代头孢菌素类动物专用抗生素,具有抗菌谱广、吸收速度快、达峰时间短、生物利用度高、对哺乳动物毒性低及对β-内酰胺酶稳定的特点,能有效治疗猪呼吸道类疾病,防止耐药性的产生。文章阐述了头孢喹肟的理化特性、杀菌机理、药动学特征等,并通过比较头孢喹肟在不同动物体内的药学参数表明头孢喹肟在猪体内达峰时间短,达峰浓度高,消除半衰期较长,能迅速发挥高效的抗菌作用,且能维持一定时间的抗菌效果;系统地介绍了头孢喹肟对猪呼吸道主要致病菌的体外抗菌活性及临床治疗效果,发现呼吸道临床病原菌对头孢喹肟敏感性高,临床应用前景广。目前头孢喹肟在临床应用存在一些问题,不合理使用会导致其出现耐药性,通过PK-PD同步模型的研究及耐药判定标准的建立,可为该药的合理应用提供科学依据。     

猪呼吸道IgA和IgG分泌细胞的分布

旨在研究猪呼吸道IgA和IgG分泌细胞的分布。取健康50日龄猪的软腭扁桃体、咽扁桃体、气管和肺组织,应用免疫组织化学技术研究猪呼吸道中IgA和IgG分泌细胞的变化。结果显示,在软腭扁桃体中,IgA和IgG分泌细胞主要分布在隐窝上皮下;在咽扁桃体中,IgA和IgG分泌细胞主要集中分布在黏膜上皮下;在气管中,IgA和IgG分泌细胞主要分布在黏膜上皮下固有层和气管腺周围,在气管上皮之间也有少量IgA分泌细胞分布;肺中的IgA和IgG分泌细胞主要集中分布在肺泡隔和各级支气管的黏膜上皮下。另外,我们观察到肺中的2种分泌细胞着色明显比气管中淡。对2种分泌细胞进行统计学分析发现,IgA分泌细胞在气管中分布最多,其次是咽扁桃体、软腭扁桃体,肺中最少;而IgG分泌细胞则在咽扁桃体中最多,其次是气管、肺,软腭扁桃体中最少。结果表明,猪呼吸道含有较多的抗体分泌细胞,但不同部位不同的抗体分泌细胞分布不尽相同,该结果可为猪呼吸道黏膜免疫及相关疫病发生机理的研究提供理论依据。     

枯草芽孢杆菌对免疫和未免疫黄河鲤免疫功能和抗病力的影响

本试验旨在研究枯草芽孢杆菌(Bacillus subtilis)对免疫和未免疫黄河鲤免疫功能和抗病力的影响.选择初始平均体重为(35.36±0.46)g的黄河鲤1 920尾,随机分为8组(Ⅰ～Ⅷ组),每组3个重复,每个重复80尾.Ⅰ～Ⅳ组为注射抗原的免疫组,Ⅴ～Ⅷ组为注射无菌生理盐水的对照组.试验饲料中枯草芽孢杆菌的添加量分别为0(Ⅰ、Ⅴ组)、1.5×1011(Ⅱ、Ⅵ组)、3.0 ×1011(Ⅲ、Ⅶ组)、4.5×1011 CFU/kg(Ⅳ、Ⅷ组).各组试验鱼在投喂试验饲料28 d后,改喂基础饲料28 d.于免疫后第7、14、21、28、35、42天测定各组试验鱼的白细胞吞噬活性、血清溶菌酶活性和血清抗体效价.于免疫后第42天采用嗜水气单孢菌对各组试验鱼进行攻毒,14 d后统计各组的死亡率,计算免疫保护率.结果表明:饲料中添加枯草芽孢杆菌能显著提高免疫和未免疫黄河鲤的白细胞吞噬百分比和吞噬指数以及血清溶菌酶活性(P＜0.05).Ⅲ组黄河鲤的血清抗体效价最高,其几何平均值为486.7;其次是Ⅳ组,为372.6;再次是Ⅱ组,为234.6;而Ⅰ组最低,为192.8.免疫组黄河鲤均获得了一定的免疫保护率,以枯草芽孢杆菌添加量为4.5×1011 CFU/kg时的免疫保护率最高.由此得出,在本试验条件下,饲料中添加枯草芽孢杆菌可提高免疫和未免疫黄河鲤的免疫功能和抗病力,建议添加量为3.0×1011～4.5×1011 CFU/kg.     

关于黄牛冻配最佳输精部位的探讨

每年选择160头可繁母牛均分成4组,通过对黄牛四个输精部位三年的研究结果,提出了输精器通过子宫颈,全部精液都输入到卵泡发育好的一侧子宫角内与将精液输入到子宫颈5～8cm处及输入到子宫分叉处,组间相比较差异显著(P<0.05)。其主要原因是此部位缩短了精子运行的距离,延长了精子的寿命,到达受精部位有受精能力的精子数量增多,有利于与卵子的结合,提高了受胎能力。因此情期受胎率较高。     

猪呼吸道淋巴组织发育的亚显微结构变化

应用组织学和电镜技术研究猪呼吸道发育过程中淋巴组织的变化。结果表明：扁桃体和咽部是呼吸道进入机体的第一个淋巴组织集中的部位，弥散淋巴组织在出生时就存在，淋巴小结不明显；20日龄时扁桃体中淋巴组织增生，淋巴小结清晰可见；120日龄淋巴小结数量增加，紧靠鳞状上皮密集排列，淋巴小结发育很好，并出现生发中心。扁桃体复层鳞状上皮中含有大量的上皮内淋巴细胞。气管叉是呼吸道进入机体的第二个淋巴组织集中的部位，出生时气管叉外膜中淋巴组织直接与气管支气管淋巴结相连，淋巴组织明显可见。20日龄时气管叉外膜中淋巴组织已分开，形成气管叉外膜密集的淋巴组织和气管支气管淋巴结两个部分。120日龄时气管叉处淋巴组织特别发达，黏膜上皮中上皮内淋巴细胞数量也显著增加。肺内气管和细支气管固有膜中均有较多的淋巴细胞，其中浆细胞数量增加，上皮中仍存在少量的上皮内淋巴细胞。本试验结果提示猪呼吸道是黏膜免疫较理想的诱导位点和效应位点，新生仔猪通过鼻腔免疫可提高呼吸道局部黏膜免疫力。     

利用ERIC-PCR和PCR-DGGE技术分析喂服枯草芽孢杆菌肉鸡肠道菌群的多样性

本文旨在采用ERIC-PCR和PCR-DGGE方法研究肉鸡喂服枯草芽孢杆菌后肠道菌群的多样性.选用15羽28日龄肉鸡,按2mL/kg BW喂服枯草芽孢杆菌悬液(10°CFU/mL).每天2次,连续3d,34日龄时,利用ERIC-PCR和PCR-DGGE方法分析肠道菌群的多样性,并对DGGE条带进行回收、测序.结果表明,肉鸡口服枯草芽孢杆菌后各肠段的条带数显著多于对照组(P<0.05或P<0.01),2种方法检测结果相似,2组之间肠道总菌群相似性为53.2%;电泳指纹图谱和统计条带数量分析,PCR-DGGE明显优于ERIC-PCR;回收条带以乳杆菌属细菌为主.结果提示,34日龄肉鸡肠道菌群具有一定的稳定性,以乳杆菌为主要菌群,饲喂芽孢杆菌后能提高肉鸡肠道菌群的丰度和种群密度;PCR-DGGE检测方法明显优于ERIC-PCR.     

Segment-dependent Expression of Muscarinic Acetylcholine Receptors and G-protein Coupling in the Equine Respiratory Tract

Muscarinic receptors are considered to be of comparable clinical importance in chronic obstructive pulmonary disease (COPD) in equines and in humans. At present, data are scarce on the expression and distribution of probable subtypes of these receptors and their signalling pathways in airway segments, including lung parenchyma and bronchial and tracheal epithelium with the underlying smooth muscle in horses. Specific [N-methyl-³H]scopolamine chloride ([³H]NMS) binding to all three tissues was saturable and of high affinity, with K _D values ranging between 1.6±0.7 and 1.9±0.3 nmol/L. [³H]NMS binding identified a higher density of total muscarinic receptors (fmol/mg protein) in the trachea (720±59 nmol/L) than in bronchi (438±48 nmol/L) or lung (22 ± 3 nmol/L). Competitive binding studies using [³H]NMS and the unlabelled subtype-selective antagonists pirenzepine and telenzepine (M₁), methoctramine and himbacine (M₂), 4-diphenylacetoxy-N-methylpiperidine (4-DAMP) (M₃), tropicamide (M₄) and mamba toxin (MT-3) (M₄) indicated the presence of at least three muscarinic receptor subtypes in peripheral lung tissue (50:40:24–28%: M₂>M₃>M₁), whereas in bronchus and trachea M₂ subtypes (87–90%) predominated over M₃ (14–22%), and M₁ subtypes were lacking. No differences were found between tissues in high-affinity binding sites for carbachol in the absence (31–36%) or presence of guanosine 5^′-triphosphate (GTP) (∼100%). Western blotting for G-protein α-subunits showed a much more robust expression of G_αi1/2 in the trachea (with highest receptor density) than in the lung or bronchi, whereas G_αs-protein was dominantly expressed in bronchus. Concomitantly, carbachol inhibited isoproterenol- and GTP-stimulated adenylyl cyclase activity with increasing muscarinic receptor expression (trachea > bronchi > lung). We conclude that the expression and signalling pathways of muscarinic receptors in the equine respiratory tract are segment-dependent. These receptors might contribute to the pathogenesis of COPD in the horse and could provide potential drug targets for the therapeutic use of anticholinergics in this species.