Some measurements of protection against paratyphoid Salmonella and Escherichia coli by competitive exclusion chickens.
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Animals↗
Biomedical subjects
O M Weinack
Publications and source records attributed to O M Weinack.
The influence of lactobacilli on the competitive exclusion of paratyphoid salmonellae in chickens.
The competitive exclusion of salmonellae by native gut microflora was investigated by treating chicks with various avian lactobacilli. The evaluation of protection was based on the number of salmonellae adhering to the mucosa of the crop and the cecum, enumeration of salmonellae in fecal droppings, and enrichment of cloacal swabs and fecal droppings using both individual and seeder bird tests. Lactobacilli reduced the number of salmonellae adhering to the crop mucosa by 1 to 2 logs. Treatment with lactobacilli did not lower the number of chickens shedding salmonellae or reduce the number of salmonellae adhering to the mucosa of the cecum. Lactobacilli as a single bacterial treatment played a minor role in protecting the crop, but no protection of the cecum was demonstrated.
Animals↗
Intestinal colonization and competitive exclusion of Campylobacter fetus subsp. jejuni in young chicks.
Colonization of Campylobacter fetus subsp. jejuni was investigated in monoxenic and holoxenic chicks. In monoxenic chicks, major colonization was found in the crop and ceca, with populations in the ceca consistently reaching 10(9) colony-forming-units/ml of cecal contents over the 28-day test period. Bacteremia was found in most chicks, but no significant gross pathological lesions were detected. In holoxenic chicks, major colonization occurred only in the ceca, and no evidence of bacteremia was detected. Colonization by native gut microflora sharply reduced subsequent colonization by C. fetus subsp. jejuni. The protective mechanism is perhaps the same as that protective against paratyphoid salmonellae and pathogenic strains of Escherichia coli.
Animals↗
Studies on the use of 9R strain of Salmonella gallinarum as a vaccine in chickens.
The 9R strain of Salmonella gallinarum produced hepatitis and splenic lesions without mortality in meat-type and brown-egg-producing strains of chicks, but not in Leghorns. It was not recovered from Leghorns for as long following vaccination as from the other strains of chicks. The infectivity of the 9R strain was determined by the genetic susceptibility and age of the host. Subcutaneous vaccination of 9R produced partial immunity to S. gallinarum in Leghorns as well as in meat-type and brown-egg-producing strains of chickens. Addition of an oil adjuvant appeared to interfere with protection and gave even less protection than did a vaccine prepared from an inactivated oil-adjuvanted smooth strain. Use of the 9R vaccine did not protect against intestinal colonization by S. typhimurium or S. infantis. Potential egg transmission of 9R following vaccination and of a pathogenic strain following challenge of vaccinated birds was indicated by ovarian infection with each strain and by isolation of the pathogenic strain from one egg. All chickens vaccinated subcutaneously with the 9R strain developed antibodies detectable by the microantiglobulin test, but only a few birds developed antibody levels detected by the whole-blood, microagglutination, and tube tests. The inactivated vaccine prepared from a smooth S. gallinarum strain produced the highest and most uniform antibody response. Antibody levels were not related to protection, which is probably dependent on cellular immunity.
Administration, Oral↗
The influence of native gut microflora on the colonization and infection of Salmonella gallinarum in chickens.
A native intestinal microflora of chickens that is protective against paratyphoid salmonellae appeared to be partially protective against Salmonella gallinarum and abbreviated the excretion time of S. gallinarum in White Leghorn chicks. Treated birds had a lower incidence of systemic infection measured by liver and spleen culture, and fewer birds developed infection in the intestinal tract. Most of the chickens positive by cloacal swabs excreted S. gallinarum throughout the test period. The low level of protection provided by competitive exclusion suggested that the practice would not prove useful in the practical control of fowl typhoid.
Animals↗
Serologic studies with Mycoplasma synoviae in experimentally inoculated chickens.
Three strains of Mycoplasma synoviae (MS) (Olson-WVU 1853, reported in 1956; and Massachusetts 9895 and 5044, respectively isolated in 1957 and 1972) were used for experimental inoculation of chickens to evaluate the various mycoplasma serologic tests. The MS plate agglutination and hemagglutination-inhibition (HI) tests were highly sensitive for detection of infection; reactions persisted for test periods extending to 63 weeks. Correlation between MS HI-tube and micro methods was good. HI titers were highest in sera from birds inoculated with strain 9895. All three strains produced cross-reactions with M. Gallisepticum (MG) plate antigens, which were detectable for 2 to 12 weeks following MS inoculation; strain 5044 produced the lowest percentage of cross-reactions. MG HI titers of 16 were observed occasionally in sera from all three group inoculated with strain 1853. It appears from these limited serologic studies in chickens that there may be antigenic differences among the three MS strains.
Agglutination Tests↗