Safety and efficacy of a Salmonella Gallinarum ΔcobSΔcbiA strain with potential to prevent chicken infections by Salmonella Gallinarum and Salmonella Enteritidis

New vaccine design techniques have allowed the development of effective vaccine strains against Salmonella infections in which the risks of reversion to the wild type and virulence is null. The mutant strain Salmonella Gallinarum ΔcobSΔcbiA was previously shown to be avirulent in chickens. In this study, this strain was tested as a vaccine against Salmonella Gallinarum (SG) and S. Enteritidis (SE) infections, and its protection levels, safety and possible risks of reversion to virulence after vaccination of layers were evaluated. Birds were vaccinated at five days of age or at five and 25 days of age. At 45 days of age, brown and white layers were challenged with SG and SE wild strains, respectively. Two assays to test the possibility of reversion to virulence were performed. Five successive bacterial passages in brown layers were carried out in the first assay. In the second assay, brown layers received a ten-fold concentrated inoculum of the SGΔcobSΔcbiA strain and were evaluated for clinical signs and mortality. In both experiments, no birds that received the inoculation of the attenuated strain died. Additionally, the use of the mutant strain as a vaccine provided good protection levels against both challenge strains.

Leucometric analysis of 1-day-old chicks inoculated with Salmonella Typhimurium or Lactobacilli

Salmonella infection is responsible for major economic losses in poultry industry. Consequently, the development of new methods for fighting such disease is desirable, such as the use of acid-lactic bacteria. However, reference values of chicks in such conditions are dissimilar to those of other species. Leucometry reference values for chicks have not been reported. The aim of this article was to evaluate and determine the leucometric values of chicks inoculated with Salmonella Typhimurium or treated with Lactobacilli probiotics. In this study, 144 1-day-old birds were divided in three groups of 48 animals each (non-treated group, Salmonella Typhimurium (ST)-inoculated group, and Lactobacilli inoculated group). A total of four blood collections were made with the first one performed 3 h after inoculation with ST or treatment with Lactobacilli. Subsequent samples were obtained every 48 h for 7 days. Leucometric evaluation was performed immediately after each collection. All birds presented an initial decrease pattern in general leukocyte values, and the chicks inoculated with ST revealed lymphomonoheteropaenic leukopaenia, eosinophilia and basophilia in conjunction with convalescence after 96 h of inoculation. The animals inoculated with Lactobacilli revealed leucocytosis with monocytosis, lymphocytosis and marked eosinopaenia. We conclude that there is no efficient bone marrow response in 1-day-old chicks challenged with Salmonella Typhimurium; additionally, an immunostimulatory effect in 1-day-old chicks treated with Lactobacilli-modulated probiotics could be stated. © 2011 Springer-Verlag London Limited.

Salmonella enteritidis in the eggs of Japanese quails (coturnix coturnix Japonica - Temminck & Schlegel, 1849) fed diets with different calcium and phosphorus levels

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Polymerase chain reaction assay based on ratA gene allows differentiation between Salmonella enterica subsp. enterica serovar Gallinarum biovars Gallinarum and Pullorum

Salmonella Pullorum and Salmonella Gallinarum are classified as biovars of Salmonella enterica subsp. enterica serovar Gallinarum. These salmonellae are the causative agents of Pullorum disease and fowl typhoid, respectively, and are widely distributed throughout the world. Although many developed countries have eradicated these diseases from commercial poultry, they are still the cause of significant economic loss in developing countries. When serovar Gallinarum is isolated, it is difficult to immediately differentiate between biovars because they are antigenically identical by serotyping. However, they cause distinct diseases with different epidemiology, and therefore it is important to differentiate them. This may be done biochemically but takes 2 to 3 days. In the present study, S. Pullorum and S. Gallinarum whole genomes were compared, and 1 genomic region of difference, which is part of the ratA gene, was chosen as a molecular marker for a polymerase chain reaction assay to differentiate rapidly between these organisms. In all, 26 strains of S. Gallinarum and 17 S. Pullorum strains were tested and successfully differentiated by the assay. © 2013 The Author(s).

Protective effect of mannan oligosaccharides against early colonization by Salmonella Enteritidis in chicks is improved by higher dietary threonine levels

Aims: To evaluate mannan oligosaccharide (MOS) and threonine effects on performance, small intestine morphology and Salmonella spp. counts in Salmonella Enteritidis-challenged birds. Methods and Results: One-day-old chicks (1d) were distributed into five treatments: nonchallenged animals fed basal diet (RB-0), animals fed basal diet and infected with Salmonella Enteritidis (RB-I), animals fed high level of threonine and infected (HT-I), birds fed basal diet with MOS and infected (MOS-I), birds fed high level of threonine and MOS and infected (HT+MOS-I). Birds were inoculated at 2d with Salmonella Enteritidis, except RB-0 birds. Chicks fed higher dietary threonine and MOS showed performance similar to RB-0 and intestinal morphology recovery at 8 dpi. Salmonella counts and the number of Salmonella-positive animals were lower in HT+MOS-I compared with other challenged groups. Conclusion: Mannan oligosaccharides and threonine act synergistically, resulting in improved intestinal environment and recovery after Salmonella inoculation. Significance and Impact of the Study: Nutritional approaches may be useful to prevent Salmonella infection in the first week and putative carcass contamination at slaughter. This is the first report on the possible synergistic effect of mannan oligosaccharides and threonine, and further studies should be performed including performance, microbiota evaluation, composition of intestinal mucins and immune assessment. © 2012 The Society for Applied Microbiology.

Effect of immersion and inoculation in ovo of Lactobacillus spp. in embryonated chicken eggs in the prevention of Salmonella enteritidis after hatch

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experimental infection of commercial layers with wild or attenuated Salmonella Gallinarum mutant strains: Anatomic pathology, total blood cell count and serum protein levels

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Produção de biofilme por Salmonella sp. isolada de frango

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fatores físico-químico e bacteriológicos do sistema de lavagem e pré-resfriamento de carcaças de frango e sua relação com a pesquisa de Salmonella spp. em carcaças pré-resfriadas

Pós-graduação em Alimentos e Nutrição - FCFAR

Infecção experimental com Salmonella typhimurium em bezerros bubalinos: estudo clínico, laboratorial e terapêutico

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo clínico, laboratorial e terapêutico da diarréia experimental em bezerros induzida por Salmonella enterica subespécie Enterica sorotipo typhimurium

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Infecção experimental por Salmonella enterica subspécie enterica sorotipo Panama e tentativa de transmissão área em leitões desmamados

Pós-graduação em Medicina Veterinária - FCAV

Identificação e avaliação in vitro da atividade inibitória de Lactobacillus spp isolados do ingúvio e cecos de aves (Gallus gallus, Linneaus, 1758), em relação a sorotipos de Salmonella

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Detecção de línfócitos T no intestino de frangos de corte tratados com lactobacillus spp. e desafiados com Salmonella enteritidis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ocorrência de Salmonella spp. em carcaças e vísceras de rãs (Rana catesbeiana - Rã de Touro): avaliação do processo de abate

Pós-graduação em Medicina Veterinária - FMVZ