鸡沙门氏菌弱毒株的效力和安全试验

将鸡沙门氏菌弱毒株以不同剂量分别经口服和颈部皮下接种1日龄商品蛋鸡进行安全性和免疫效力研究,结果表明：该弱毒株对1日龄雏鸡有良好的安全性并能提供较强的保护力。     

减毒鸡沙门菌疫苗株97A的免疫保护效力试验

减毒沙门菌疫苗株97A免疫鸡经鸡沙门菌强毒株Sg9攻击后,对免疫攻毒组和攻毒对照组鸡进行病理学检查和细菌分离,以进一步评价97A疫苗的免疫保护效力。结果表明,免疫攻毒组鸡肝脏、肺脏和肾脏等实质器官仅有轻到中度的炎症反应,而攻毒对照组鸡则表现出了严重的组织病理学变化,同时减毒鸡沙门菌疫苗株97A能显著地限制强毒株在鸡体内的定居和增殖,显示出了良好的免疫保护效力。     

减毒鸡沙门氏菌97A疫苗株安全性和免疫效力试验

本试验将减毒鸡沙门氏菌97A疫苗株分别以不同剂量经口服和肌肉注射接种10日龄AA肉鸡，结果表明，97A对10日龄雏鸡有良好安全性。将97A分别以10     

The selection of Salmonella gallinarum, Salmonella pullorum and Escherichia coli in chickens after chloramphenicol administration]

The effect of a chloramphenicol administration was examined on the selection of E. coli of the chicken intestinal flora, and of the infectious S. gallinarum and S. pullorum strains. On the other hand, an effort was made to detect the frequency of the resistance transmission of E. coli to above mentioned sensitive salmonella strains. Fourteen chicken, 12 infected and 2 negative controls were used. It was found that the enteric E. coli strains became resistant in a week's time. Besides, the strains that were used for infecting the chicken neither were selected through the chloramphenicol administered nor did they take the E. coli resistance, via R-factor transmission.     

Virulence analysis of a Salmonella gallinarum strain by oral inoculation of 20-day-old chickens

In order to know the effect of in vitro passages on the pathogenicity of the Salmonella gallinarum strain INTA 91, a lyophilized culture was compared with the same strain recently isolated from a sick bird. The mean lethal dose (LD50) of the orally administered lyophilized culture was determined as 2.04 x 10(8) colony-forming units (CFU)/chicken. There was no correlation between the LD50 dose and the degree of disease produced; doses 10 or 100 times higher than the calculated LD50 did not produce a more severe disease. In trial 1, chickens were challenged with 1.02 x 10(9) CFU per chicken (5LD50) of the lyophilized strain and reached 52.2% mortality at the end of the assay. In trial 2, three different groups of chickens were infected with a recent isolate of the same strain: 2.04 x 10(8) CFU/chicken, 4.1 x 10(8) CFU/chicken, and 2.1 x 10(9) CFU/chicken (i.e., 1LD50, 2LD50, and 10LD50 of the dose calculated for the lyophilized strain, respectively). These chicken groups presented higher mortality rates (90%, 100%, and 95%, respectively) than previous trials, showing that the S. gallinarum strain used here increased its virulence by in vivo infected chicken passage. In all assays, the disease started after an incubation period of around 5-6 days. To obtain reliable and reproducible results in future challenge experiments, a fixed limited number of in vitro passages of the S. gallinarum strain must be determined.     

Use of membrane proteins from Salmonella gallinarum for prevention of fowl typhoid infection in chickens

Outer membrane protein isolated from Salmonella gallinarum was examined at different concentrations with or without a mineral-oil adjuvant for its immunogenicity and protection against live challenge. A formalin-killed whole-cell bacterin of the same organism was used for comparison. The results suggested that membrane proteins from S. gallinarum give better protection than formalin-killed whole-cell bacterin. Addition of an oil adjuvant to the protein appeared to increase the efficiency of the vaccine. When protein was given to chickens at 400 micrograms/100 g of live body weight, it produced 100% protection against oral challenge with S. gallinarum.     

Salmonella gallinarum field isolates of the biovars pullorum and gallinarum

In 40 cases salmonellae of the serovar Salmonella (S.) gallinarum were culturally isolated from domesticated gallinaceous birds submitted for diagnostic purposes in the period of 1979-1989. On the basis of the cultural and biochemical features found 35 of them could be assigned to the biovar Pullorum and 5 to the biovar Gallinarum. Of 35 isolates of the biovar Pullorum, 29 were isolated from pure bred chickens of small fancy-exhibition type flocks, 4 from floor-housed adult brown hybrid laying hens and one each from broiler chicks and pheasant chicks (Phasianus colchicus). Acute to subacute courses of the pullorum disease were observed in the 4 flocks of brown hybrid hens. Of 5 isolates of the biovar Gallinarum, 4 were isolated from adult brown hybrid laying hens kept in battery cages and one from floor-housed brown hybrid pullets of the laying type. First cases of fowl typhoid occurred early in the summer of 1988. The disease was characterized by a peracute course in the 4 flocks of brown laying hens and by a more acute course in the pullet flock. The primary source of the fowl typhoid producing organisms was not elucidated.     

Salmonella contamination in commercial layer feed in Japan

A total of 4,418 samples of commercial layer feeds obtained in 1998 were investigated for the presence of salmonellae. A total of 146 strains of salmonellae which consisted of 32 serovars, including 20 strains of Salmonella Enteritidis, were isolated from 143 feed samples.     

Vaccination against Salmonella enteritidis in Dutch commercial layer flocks with a vaccine based on a live Salmonella gallinarum 9R strain: evaluation of efficacy, safety, and performance of serologic Salmonella tests

This study describes a field trial in which 80 commercial layer flocks, with an increased risk of Salmonella enteritidis (SE) infection and placed on farms with a certified Standardized Biosecurity Programme (SBP) or a request for a SBP certificate, were vaccinated with a vaccine based on a live attenuated Salmonella gallinarum (SG) 9R strain. An evaluation is presented of the efficacy of the vaccine against SE infections, the effect on the performance of serologic Salmonella tests, and the spread of the vaccine strain to the egg content. For the efficacy study, assessment of the flock level occurrence of SE infections in the vaccinated group of 80 flocks was compared with that of a nonvaccinated group of 1854 flocks hatched in the same period. This control group was examined according to the compulsory control programme in The Netherlands. An evaluation was done of the performance of serologic Salmonella tests and the spread of the vaccine strain to the inner egg content of five of the vaccinated flocks. Findings demonstrated the flock level occurrence of SE infections in the vaccinated group (2/80 = 2.5%) to be significantly (P = 0.01) lower than that of the nonvaccinated group (214/1854 = 11.5%). Vaccination resulted in 59.0% positive test results in lipopolysaccharide BD enzyme-linked immunosorbent assay (ELISA) for detecting antibodies against Salmonella serogroups B and D and 0% positive test results in the rapid plate agglutination test for detecting antibodies against S. pullorum (SP)/SG. The mean specificities of two blocking ELISAs (gm- and i-double antibody sandwich ELISAs) based on the flagellar antigen of SE and Salmonella typhimurium (ST) on the same sera were 99.6% and 96.1%, respectively. The vaccine strain could not be isolated from any of the 450 pools of 10 eggs. On the basis of these results, we concluded that vaccination with a vaccine based on an attenuated SG 9R strain contributes to the reduction of SE infections in commercial layer flocks. Furthermore, serologic monitoring of SE, ST, and SP/SG can still be carried out on flocks vaccinated with an attenuated SG 9R strain. Additionally, we found no indication of the spread of the vaccine strain to the egg content.     

鸡白痢沙门菌和鸡伤寒沙门菌PCR-RFLP鉴别

根据鸡白痢沙门菌和鸡伤寒沙门菌flic基因可变区两端的保守序列设计1对引物,PCR扩增出约866 bp的产物,用HinplI对PCR产物进行酶切,经RFLP分析区分鸡白痢沙门菌和鸡伤寒沙门菌.利用该技术对1株鸡白痢沙门菌标准株及2株鸡伤寒沙门菌标准株进行分子鉴别,结果与预计的RFLP模式相符,证明该方法可行.在此基础上...     

A self-propelled, constant-speed spray vaccinator for commercial layer chickens

Vaccination of commercial layer chickens is labor intensive and often results in poor rates of seroconversion, which, in turn, generally correlate with decreased flock uniformity and performance. Attempts to improve the vaccination process include numerous variations of individual shop-built vaccinators in use by the layer sector of the poultry industry. Each of these vaccinators has limitations that contribute to poor vaccinations. Major problems include the nonuniform speed of the applicator system and pressure fluctuations at the spray nozzles, which contribute to sporadic dispersion of the vaccine as the vaccinator is pushed or carried past the cages. A battery-powered, self-propelled, constant-speed vaccinator was designed and constructed that operates with constant nozzle pressure. In field use, this vaccinator has resulted in both labor savings (reduction of manpower from five to one to vaccinate 75,000 chickens) and time savings (from 45 min to 7.5 min/poultry house) as well as improved vaccination results (higher positive seroconversion rates) against the poultry pathogen Mycoplasma gallisepticum (MG), a bacterium associated with losses of 15.7 eggs/hen over a 45-wk laying period in MG-infected layers as compared with layers maintained free from infection with MG.     

Cell-mediated and humoral immune responses to a virulent plasmid-cured mutant strain of Salmonella enterica serotype gallinarum in broiler chickens

One-week-old Salmonella-free broiler chicks were subcutaneously immunized and subsequently boosted two weeks later with 2x10(7)cfu 0.5ml(-1) of an 85-kb virulent plasmid-cured spectinomycin-resistant mutant strain (SG9VP(-)Spc(r)) of Salmonella gallinarum 9 (S. enterica serotype gallinarum 9) along with a control group of mock-immunized chickens. The chicks were subcutaneously challenged at 5 weeks of age with 5x10(10)cfu 0.5ml(-1) (5xLD(50)) of wild-type S. gallinarum var. Duisburg (S. enterica serotype gallinarum var. Duisburg). The cellular and humoral immune responses were measured at weekly intervals post-immunization (PI) and post-challenge (PC) using lymphocyte stimulation test (LST), delayed type hypersensitivity (DTH) test, serum tube agglutination test (STAT) and enzyme-linked immunosorbent assay (ELISA). High stimulation indices suggestive of a potent lymphocyte transformation response and high persistent serum IgG titres were recorded in immunized chickens at the termination of the experiment. These findings indicate that the live attenuated mutant vaccine induced a strong cellular and humoral immunity, which may play a role in the protection of fowl typhoid in broiler chickens.     

Efficacy studies on Haemophilus gallinarum bacterin preparations.

Broth cultures inactivated and potentiated by selected methods were tested in chickens for efficacy against homologous and heterologous challenge inoculation, using 2 serotype A strains of Haemophilus gallinarum. Although the 2 strains were within the same serotype, they failed to cross protect. One dose of thimerosal-inactivated bacterin was protective against homologous challenge, but 2 doses of formalin-inactivated bacterin were required. A bivalent bacterin protected chickens well against 1 strain, but not the other, at the 1-dose level.     

A chronicle of serologic response in commercial layer chickens to vaccination with commercial F strain Mycoplasma gallisepticum vaccine

Vaccination of multi-age layer operations, wherein one million plus commercial layer chickens are housed, has been spurious until the development of a self-propelled, constant-speed spray vaccinator. Still, even with its use, live Mycoplasma gallisepticum (MG) vaccinations have been questionable in terms of seroconversion. Using the vaccinator as a research tool over the past 5 yr, factors have been elucidated which impact seroconversion to one live MG vaccine in particular, the F strain of MG (FMG). These factors include the type of nozzle used to spray the vaccine, the temperature of the water used to rehydrate and administer the vaccine, and the pH and osmolarity of the fluid used to apply the vaccine. In the present study, one farm was monitored for its seroconversion rates over 4 1/2 yr, during which time the FMG vaccination protocol was amended as factors were identified that enhanced seroconversion rates. The results of this study showed that implementation and inclusion of the optimized factors into the vaccination protocol for FMG enhanced seroconversion rates because they went from an initial 50%-55% positive seroconversion rate to a consistent 100% positive seroconversion rate over the 56-mo study period.     

Effect of ochratoxin A on broiler chicks challenged with Salmonella gallinarum

1. A study was conducted to evaluate the effects of ochratoxin A (OA) on broiler chicks challenged with Salmonella gallinarum. 2. One hundred and seventy-six 1-d-old broiler chicks were divided into two groups of 88 chicks each, with one group fed on a control mash diet and the other given a mash diet containing 2 ppm OA. On d 14, each group was further subdivided into two groups with one group infected with S. gallinarum and the other uninfected. 3. Following S. gallinarum inoculation on d 14, 4 birds from each group were killed at 1, 2, 3, 5, 7, 10, 14 and 21 d post inoculation. 4. S. gallinarum infection caused dullness, depression, weakness, increased thirst, droopy wings, ruffled feathers and greenish-yellow diarrhoea. S. gallinarum infection in the absence of OA caused 11.5% mortality which increased to 28.8% in the presence of OA. 5. Decreased body weight and reduced feed intake were observed in chicks fed on the diet containing OA. S. gallinarum infection also reduced the body weights of chicks, with the effects being more marked in chicks receiving OA. The OA diet led to increased serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, uric acid and creatinine, and decreased levels of total proteins, albumin, globulins, calcium and phosphorus. S. gallinarum infection did not cause significant alteration in any of the serum biochemical parameters. 6. Mortality and the severity of S. gallinarum infection in broiler chicks were increased by the presence of OA in the diet.     

双重放大酶免疫传感器检测鸡白痢鸡伤寒沙门菌

为探求新型鸡白痢鸡伤寒沙门菌快速检测技术,本研究首次利用多壁碳纳米管与离子液体[BMIM] PF6修饰四通道丝网印刷碳电极,制成双重放大信号检测鸡白痢鸡伤寒沙门菌的酶免疫传感器.用原子力显微镜表征其表观形态,循环伏安法监测其电化学特性.结果表明,在优化的检测条件下,免疫电极对目标菌的线性响应范围为103～109 cfu· mL-1,检出限为3.93×102 cfu·mL-1(S/N=3),4℃放置28 d后,响应电流为初始值的90.15％,具有良好的稳定性、特异性、重现性和准确性.多壁碳纳米管与离子液体结合制备的鸡白痢鸡伤寒沙门菌酶免疫传感器实现了检测信号的双重放大,检测灵敏度高,离子液体有助于保持酶标抗体的活性,延长免疫电极的有效时间.依据该方法构建的酶免疫传感器为快速检测其它致病菌酶免疫传感器的研究提供了良好的参照模型.