RESUMO
In recent years, egg production has had an intense growth in Brazil, and Brazilian egg consumption per capita has significantly increased in the last decade. To reduce sanitary and financial risks, decisions regarding the production and health status of the flock must be made based on objective criteria. Our aim was to determine the main "input" variables for the prediction of egg production performance in commercial laying breeder flocks using an ANN model. The software NeuroShellClassifier and NeuroShell Predictor were used to build the ANN. A total of 26 egg-production traits were selected as input variables and eight as output variables. A database of 44,120 Excel cells was generated. For the training and validation of the models, 74.9% and 25.1% of the data were used, respectively. The accuracy of the ANN models was calculated and compared using the analysis of coefficient of multiple determination (R2), mean squared error (MSE), and an assessment of uniform scatter in the residual plots. The models for the outputs "weekly egg production," "weekly incubated egg,", "accumulated commercial egg," and "viability" showed an R2 greater than 0.8. Other models yielded R2 values lower than 0.8. The ANN predicts adequately eight egg-production traits in the breeders of commercial laying hens. The method is an option for data management analysis in the egg industry, providing estimates of the relative contribution of each input variable to the outputs.(AU)
Assuntos
Animais , Galinhas , Redes Neurais de Computação , Ovos/análise , Produtos Avícolas/análise , Simulação por ComputadorRESUMO
Campylobacteriosis is one of the most common foodborne diseases in the world. It is considered the most frequently reported foodborne illness in the European Union (EU) and one of the most important in the United States (US) (EFSA & ECDC, 2018; CDC, 2019a; WHO, 2019). Poultry is known to be the major reservoir and an important source for pathogen transmission to humans (Kaakoush et al., 2015). Campylobacteriosis is most often associated with the consumption of raw and undercooked poultry or the cross-contamination of other foods by these items (CDC, 2019a). Although Brazil is a leading supplier of the worlds poultry meat (ABPA, 2018), Brazils official data does not report Campylobacter infections.(AU)
Assuntos
Animais , Campylobacter jejuni/imunologia , Anti-Infecciosos/classificação , DNA Girase , Aves/imunologia , Aves/microbiologiaRESUMO
Campylobacteriosis is one of the most common foodborne diseases in the world. It is considered the most frequently reported foodborne illness in the European Union (EU) and one of the most important in the United States (US) (EFSA & ECDC, 2018; CDC, 2019a; WHO, 2019). Poultry is known to be the major reservoir and an important source for pathogen transmission to humans (Kaakoush et al., 2015). Campylobacteriosis is most often associated with the consumption of raw and undercooked poultry or the cross-contamination of other foods by these items (CDC, 2019a). Although Brazil is a leading supplier of the worlds poultry meat (ABPA, 2018), Brazils official data does not report Campylobacter infections.
Assuntos
Animais , Anti-Infecciosos/classificação , Aves/imunologia , Aves/microbiologia , Campylobacter jejuni/imunologia , DNA GiraseRESUMO
Salmonella spp. remain among the most important agents of foodborne diseases worldwide. The importance of Salmonella spp. in public health is linked to their wide range of antimicrobial resistance and to their pathogenicity and virulence in both human and animal hosts. The aim of this study was to determine the antimicrobial resistance patterns for Salmonella serotypes isolated from poultry sources in Brazil and to detect virulence-associated genes and verify their association with specific serotypes. A total of 163 strains of Salmonella enterica isolated from poultry sources in Southern Brazil were selected, and each belonged to one of 11 different serotypes. They were tested against ten antibiotics and examined for the presence of 26 virulence-associated genes by PCR. S. Typhimurium, S. Bredeney, S. Schwarzengrund and S. Tennessee showed the highest overall resistance rates. Approximately 18% of Salmonella strains were classified as multidrug-resistant strains. Our results indicate associations between antimicrobial resistance and specific serotypes. Most of the investigated genes presented a high frequency and a regular distribution, regardless of the serotype. Eight genes are positively or negatively associated with at least one serotype. The observed associations between antimicrobial resistance and specific serotypes are useful in developing specific control and treatment measures for each serotype. Despite the virulence genes being evenly distributed among the serotypes, some of these genes are associated with specific serotypes, and sefA, sopEand lpfA were selected as possible markers of Salmonella serotypes.(AU)
Assuntos
Animais , Aves/microbiologia , Anti-Infecciosos , Salmonella enterica/patogenicidade , SorogrupoRESUMO
Salmonella spp. remain among the most important agents of foodborne diseases worldwide. The importance of Salmonella spp. in public health is linked to their wide range of antimicrobial resistance and to their pathogenicity and virulence in both human and animal hosts. The aim of this study was to determine the antimicrobial resistance patterns for Salmonella serotypes isolated from poultry sources in Brazil and to detect virulence-associated genes and verify their association with specific serotypes. A total of 163 strains of Salmonella enterica isolated from poultry sources in Southern Brazil were selected, and each belonged to one of 11 different serotypes. They were tested against ten antibiotics and examined for the presence of 26 virulence-associated genes by PCR. S. Typhimurium, S. Bredeney, S. Schwarzengrund and S. Tennessee showed the highest overall resistance rates. Approximately 18% of Salmonella strains were classified as multidrug-resistant strains. Our results indicate associations between antimicrobial resistance and specific serotypes. Most of the investigated genes presented a high frequency and a regular distribution, regardless of the serotype. Eight genes are positively or negatively associated with at least one serotype. The observed associations between antimicrobial resistance and specific serotypes are useful in developing specific control and treatment measures for each serotype. Despite the virulence genes being evenly distributed among the serotypes, some of these genes are associated with specific serotypes, and sefA, sopEand lpfA were selected as possible markers of Salmonella serotypes.
Assuntos
Animais , Anti-Infecciosos , Aves/microbiologia , Salmonella enterica/patogenicidade , SorogrupoRESUMO
Fowl cholera is a contagious disease that results from infection by the bacterium Pasteurella multocida. This microorganism is extensively distributed among animal species, but little is known regarding its pathogenesis and specificity to various hosts. Many studies using pathogenicity evaluation methods are subjective and difficult to quantify because they are often only involved in the observation of the lethal capacity of the agent in experimental inoculation. Due to a lack of more consistent data, this study aimed to establish a classification model of P. multocida pathogenicity in mice using strains isolated from poultry and swine. A total of 94 strains of P. multocida isolated from clinical cases of FC and from lungs of swine were tested. A volume of 0.1 mL of bacterial suspension was obtained from the concentration of 106 CFU/mL and inoculated by an intraperitoneal route in five mice. The animals were observed every six hours over seven days. In addition to the mortality observed, the time of death and gross lesions were also analyzed. The Pathogenicity Indexes obtained showed significant differences (p<0.05) according to the origin of the strains. Likewise, the number of gross lesions and isolation percentages were also varied (p<0.05) among strains isolated from poultry and swine. From the observed ratios, the isolates were grouped into three pathogenicity classes: high, medium and low. This study proposed a consistent measurement and classification of P. multocida pathogenicity. The obtained results will be used to generate other adjusted models, as well as to form the basis for disease diagnosis.(AU)
Assuntos
Animais , Ratos , Camundongos/microbiologia , Pasteurella multocida/patogenicidade , Aves/microbiologiaRESUMO
Fowl cholera is a contagious disease that results from infection by the bacterium Pasteurella multocida. This microorganism is extensively distributed among animal species, but little is known regarding its pathogenesis and specificity to various hosts. Many studies using pathogenicity evaluation methods are subjective and difficult to quantify because they are often only involved in the observation of the lethal capacity of the agent in experimental inoculation. Due to a lack of more consistent data, this study aimed to establish a classification model of P. multocida pathogenicity in mice using strains isolated from poultry and swine. A total of 94 strains of P. multocida isolated from clinical cases of FC and from lungs of swine were tested. A volume of 0.1 mL of bacterial suspension was obtained from the concentration of 106 CFU/mL and inoculated by an intraperitoneal route in five mice. The animals were observed every six hours over seven days. In addition to the mortality observed, the time of death and gross lesions were also analyzed. The Pathogenicity Indexes obtained showed significant differences (p<0.05) according to the origin of the strains. Likewise, the number of gross lesions and isolation percentages were also varied (p<0.05) among strains isolated from poultry and swine. From the observed ratios, the isolates were grouped into three pathogenicity classes: high, medium and low. This study proposed a consistent measurement and classification of P. multocida pathogenicity. The obtained results will be used to generate other adjusted models, as well as to form the basis for disease diagnosis.
Assuntos
Animais , Ratos , Aves/microbiologia , Camundongos/microbiologia , Pasteurella multocida/patogenicidadeRESUMO
Fowl Cholera (FC) is a disease caused by Pasteurella multocida. The severity of this disease is partly caused by virulence factors. Genes encoding fimbriae, capsule, sialidases and proteins for iron metabolism may be related to P. multocida's ability to infect the host. Besides to examining DNA for the presence of virulence genes, DNA is essential for the diagnostic and FTA cards are an alternative for genetic material transport. The study aims to evaluate the viability of P. multocida DNA transport using the cards and to detect 14 virulence genes in 27 strains isolated from FC cases in the United States by multiplex-PCR. No growth was observed in any of the FTA cards, which was essential to assess the security. Furthermore, DNA detection was possible in 100% of the samples, independent of the storage period (7 to 35 days) and temperature (4°C and 37°C). ptfA, exbd-tonB, hgbA, nanB, oma87, hyaD-hyaC, sodC, hgbB, sodA, nanH and pfhA genes were detected in more than 80% of the samples. FTA cards have proven to be a viable and safe tool for DNA transport of P. multocida. A majority of genes showed a high frequency, which was similar to strains isolated from FC cases.(AU)
Cólera aviária (CA) é uma doença causada pela bactéria Pasteurella multocida e a severidade dos casos é em parte justificada por fatores de virulência. Genes codificando fímbrias, cápsulas, sialidases, dismutases e proteínas do metabolismo férrico podem ser relacionados à capacidade do agente em infectar o hospedeiro. Além da obtenção do DNA para pesquisa de genes de virulência, o material genético é fundamental para o diagnóstico, e os cartões FTA seriam uma alternativa no transporte de microrganismos. Os objetivos da presente pesquisa foram avaliar a viabilidade do transporte de DNA de P. multocida através dos cartões e detectar 14 genes de virulência em 27 cepas isoladas de CA nos Estados Unidos, por meio de multiplex-PCR. Nenhuma das amostras para análise microbiológica da segurança dos cartões apresentou crescimento. Foi possível a detecção do DNA em 100% das amostras, independentemente do tempo de estocagem (sete a 35 dias) e das temperaturas (4°C e 37°C) avaliadas. Genes ptfA, exbd-tonB, hgbA, nanB, oma87, hyaD-hyaC, sodC, hgbB, sodA, nanH e pfhA foram detectados em mais de 80% das amostras. Os cartões FTA demonstraram ser uma ferramenta viável e segura para o transporte do DNA de P. multocida. A maioria dos genes apresentou uma alta frequência, compatível com isolados de CA.(AU)
Assuntos
Pasteurella multocida/genética , Pasteurella multocida/patogenicidade , Fatores de Virulência/isolamento & purificaçãoRESUMO
Fowl Cholera (FC) is a disease caused by Pasteurella multocida. The severity of this disease is partly caused by virulence factors. Genes encoding fimbriae, capsule, sialidases and proteins for iron metabolism may be related to P. multocida's ability to infect the host. Besides to examining DNA for the presence of virulence genes, DNA is essential for the diagnostic and FTA cards are an alternative for genetic material transport. The study aims to evaluate the viability of P. multocida DNA transport using the cards and to detect 14 virulence genes in 27 strains isolated from FC cases in the United States by multiplex-PCR. No growth was observed in any of the FTA cards, which was essential to assess the security. Furthermore, DNA detection was possible in 100% of the samples, independent of the storage period (7 to 35 days) and temperature (4°C and 37°C). ptfA, exbd-tonB, hgbA, nanB, oma87, hyaD-hyaC, sodC, hgbB, sodA, nanH and pfhA genes were detected in more than 80% of the samples. FTA cards have proven to be a viable and safe tool for DNA transport of P. multocida. A majority of genes showed a high frequency, which was similar to strains isolated from FC cases.(AU)
Cólera aviária (CA) é uma doença causada pela bactéria Pasteurella multocida e a severidade dos casos é em parte justificada por fatores de virulência. Genes codificando fímbrias, cápsulas, sialidases, dismutases e proteínas do metabolismo férrico podem ser relacionados à capacidade do agente em infectar o hospedeiro. Além da obtenção do DNA para pesquisa de genes de virulência, o material genético é fundamental para o diagnóstico, e os cartões FTA seriam uma alternativa no transporte de microrganismos. Os objetivos da presente pesquisa foram avaliar a viabilidade do transporte de DNA de P. multocida através dos cartões e detectar 14 genes de virulência em 27 cepas isoladas de CA nos Estados Unidos, por meio de multiplex-PCR. Nenhuma das amostras para análise microbiológica da segurança dos cartões apresentou crescimento. Foi possível a detecção do DNA em 100% das amostras, independentemente do tempo de estocagem (sete a 35 dias) e das temperaturas (4°C e 37°C) avaliadas. Genes ptfA, exbd-tonB, hgbA, nanB, oma87, hyaD-hyaC, sodC, hgbB, sodA, nanH e pfhA foram detectados em mais de 80% das amostras. Os cartões FTA demonstraram ser uma ferramenta viável e segura para o transporte do DNA de P. multocida. A maioria dos genes apresentou uma alta frequência, compatível com isolados de CA.(AU)
Assuntos
Pasteurella multocida/genética , Pasteurella multocida/patogenicidade , Fatores de Virulência/isolamento & purificaçãoRESUMO
Salmonella Enteritidis and Salmonella Typhimurium are responsible for causing huge economic loses in aviculture, as they lead young broiler chicks to develop clinical disease and thus increase mortality. Salmonella's pathogenicity is considered complex and multifactorial, demanding more studies that could elucidate the interaction between host and pathogen. The present study aims to evaluate the virulence of 130S. Enteritidis isolates and 70S. Typhimurium inoculated in one-day-old chicks through the establishment of a pathogenicity index. For each strain, 10 commercial chicks from the Cobb lineage were used. Then, 200µL of a solution containing 2x108 CFU of S. Enteritidis or S. Typhimurium were inoculated in the birds by intraperitoneal via. Mortality and presence of lesions such as aerosaculitis (A), perihepatitis (Ph), pericarditis (Pc), peritonitis (Pt), onfalitis (O) and cellulitis (C) were registered daily for seven days. From the second to the seventh day there was a proportional decrease in the punctuation of the time of death (TD) for each day that the bird had survived. The pathogenicity index was calculated using the following formula: PI = (TD x 5) + A + Ph + Pc + Pt + O + C. The obtainment of the PI of each bacterial sample was achieved by calculating the rate of the ten inoculated birds. Based on the obtained results, it was possible to attribute the pathogenicity value for each strain, which enabled us to classify them in groups of low (27/200), intermediate (95/200) and high (78/200) pathogenicity. The utilization of standards like time of death and presence of septicemic lesions made it possible to determine the pathogenicity rate for each strain. Besides that, the proposed model has presented dramatic differences between the high, intermediate and low pathogenicity groups, which makes this mechanism useful for further classification of strains isolated in poultry farms.
Salmonella Enteritidis e Salmonella Typhimurium são responsáveis por imensos prejuízos econômicos ao setor avícola, podendo levar ao desenvolvimento de doença clínica e ao aumento da mortalidade em aves jovens. A patogenicidade de Salmonella é considerada complexa e multifatorial, necessitando de estudos que possam esclarecer a interação entre patógeno e hospedeiro. O presente trabalho teve por objetivo avaliar a virulência de 130 isolados de S. Enteritidis e 70 de S.Typhimurium, inoculadas em pintos de um dia de idade, por meio do estabelecimento de um índice de patogenicidade. Para cada cepa, foram utilizados 10 pintos comerciais da linhagem Cobb. As aves foram inoculadas com 200µL de uma solução contendo 2x108 UFC de S. Enteritidis ou S. Typhimurium, por via intraperitoneal. A mortalidade e a presença de lesões como aerossaculite (A), peri-hepatite (Ph), pericardite (Pc), peritonite (Pt), onfalite (O) e celulite (C) foram registradas diariamente durante sete dias. Do segundo ao sétimo dia, houve uma diminuição proporcional da pontuação no tempo de morte (TM) a cada dia em que o animal sobrevivia. O cálculo do índice de patogenicidade de cada pintinho inoculado (IP) obedeceu à seguinte fórmula: IP = (TMx5) + A + Ph + Pc + Pt + O + C. Para obtenção do IP de cada amostra, foi realizada a média do IP obtido com as 10 aves inoculadas. Com base nos resultados observados, foi possível atribuir um valor de patogenicidade a cada uma das cepas, permitindo classificá-las em grupos de baixa (27/200), intermediária (95/200) e alta patogenicidade (78/200). A utilização de critérios, como tempo de morte e presença de lesões septicêmicas, permitiu a determinação de um índice de patogenicidade para cada cepa. Além disso, o modelo proposto apresentou diferença significativa entre os grupos de alta, intermediária e baixa patogenicidade, permitindo, assim, a sua aplicação para classificação futura das cepas isoladas em granjas avícolas.
Assuntos
Animais , Aves Domésticas , Salmonella enteritidis/patogenicidade , Salmonella typhimurium/patogenicidade , Salmonelose Animal/patologia , Interações Hospedeiro-Patógeno , Fatores de VirulênciaRESUMO
Salmonella Enteritidis and Salmonella Typhimurium are responsible for causing huge economic loses in aviculture, as they lead young broiler chicks to develop clinical disease and thus increase mortality. Salmonella's pathogenicity is considered complex and multifactorial, demanding more studies that could elucidate the interaction between host and pathogen. The present study aims to evaluate the virulence of 130S. Enteritidis isolates and 70S. Typhimurium inoculated in one-day-old chicks through the establishment of a pathogenicity index. For each strain, 10 commercial chicks from the Cobb lineage were used. Then, 200µL of a solution containing 2x108 CFU of S. Enteritidis or S. Typhimurium were inoculated in the birds by intraperitoneal via. Mortality and presence of lesions such as aerosaculitis (A), perihepatitis (Ph), pericarditis (Pc), peritonitis (Pt), onfalitis (O) and cellulitis (C) were registered daily for seven days. From the second to the seventh day there was a proportional decrease in the punctuation of the time of death (TD) for each day that the bird had survived. The pathogenicity index was calculated using the following formula: PI = (TD x 5) + A + Ph + Pc + Pt + O + C. The obtainment of the PI of each bacterial sample was achieved by calculating the rate of the ten inoculated birds. Based on the obtained results, it was possible to attribute the pathogenicity value for each strain, which enabled us to classify them in groups of low (27/200), intermediate (95/200) and high (78/200) pathogenicity. The utilization of standards like time of death and presence of septicemic lesions made it possible to determine the pathogenicity rate for each strain. Besides that, the proposed model has presented dramatic differences between the high, intermediate and low pathogenicity groups, which makes this mechanism useful for further classification of strains isolated in poultry farms.(AU)
Salmonella Enteritidis e Salmonella Typhimurium são responsáveis por imensos prejuízos econômicos ao setor avícola, podendo levar ao desenvolvimento de doença clínica e ao aumento da mortalidade em aves jovens. A patogenicidade de Salmonella é considerada complexa e multifatorial, necessitando de estudos que possam esclarecer a interação entre patógeno e hospedeiro. O presente trabalho teve por objetivo avaliar a virulência de 130 isolados de S. Enteritidis e 70 de S.Typhimurium, inoculadas em pintos de um dia de idade, por meio do estabelecimento de um índice de patogenicidade. Para cada cepa, foram utilizados 10 pintos comerciais da linhagem Cobb. As aves foram inoculadas com 200µL de uma solução contendo 2x108 UFC de S. Enteritidis ou S. Typhimurium, por via intraperitoneal. A mortalidade e a presença de lesões como aerossaculite (A), peri-hepatite (Ph), pericardite (Pc), peritonite (Pt), onfalite (O) e celulite (C) foram registradas diariamente durante sete dias. Do segundo ao sétimo dia, houve uma diminuição proporcional da pontuação no tempo de morte (TM) a cada dia em que o animal sobrevivia. O cálculo do índice de patogenicidade de cada pintinho inoculado (IP) obedeceu à seguinte fórmula: IP = (TMx5) + A + Ph + Pc + Pt + O + C. Para obtenção do IP de cada amostra, foi realizada a média do IP obtido com as 10 aves inoculadas. Com base nos resultados observados, foi possível atribuir um valor de patogenicidade a cada uma das cepas, permitindo classificá-las em grupos de baixa (27/200), intermediária (95/200) e alta patogenicidade (78/200). A utilização de critérios, como tempo de morte e presença de lesões septicêmicas, permitiu a determinação de um índice de patogenicidade para cada cepa. Além disso, o modelo proposto apresentou diferença significativa entre os grupos de alta, intermediária e baixa patogenicidade, permitindo, assim, a sua aplicação para classificação futura das cepas isoladas em granjas avícolas.(AU)
Assuntos
Animais , Salmonella enteritidis/patogenicidade , Salmonella typhimurium/patogenicidade , Salmonelose Animal/patologia , Aves Domésticas , Fatores de Virulência , Interações Hospedeiro-PatógenoRESUMO
Campylobacter jejuni is recognized as a leading cause of acute bacterial gastroenteritis in humans. The over-use of antimicrobials in the human population and in animal husbandry has led to an increase in antimicrobial-resistant infections, particularly with fluoroquinolones and macrolides. The aim of the present study was to provide information of the current status of antimicrobial resistance patterns in Campylobacter jejuni from poultry sources. Fifty strains were recovered from broiler slaughterhouses in Rio Grande do Sul state, Brazil, 2012. The strains were investigated for antimicrobial susceptibility against three agents (ciprofloxacin, nalidixic acid and erythromycin) by minimal inhibitory concentrations. The strains were analysed by polymerase chain reaction-restriction fragment length polymorphism for detection of the Thr-86 mutation that confers resistance to ciprofloxacin. In addition, all the strains were tested for the presence of efflux systems (cmeB gene) conferring antimicrobial resistance. The minimum inhibitory concentrations results showed that 98% of isolates were sensitive to erythromycin and most isolates were resistant to ciprofloxacin (94%) and nalidixic acid (90%). A complete correlation was observed between the minimum inhibitory concentrations and PCR-RFLP assay. Finally, the cmeB gene that is responsible for multidrug resistance was detected in 16 isolates out the 50 strains (32%).
Assuntos
Antibacterianos/farmacologia , Infecções por Campylobacter/veterinária , Campylobacter jejuni/genética , Galinhas/microbiologia , Fluoroquinolonas/farmacologia , Macrolídeos/farmacologia , Doenças das Aves Domésticas/microbiologia , Matadouros , Animais , Brasil/epidemiologia , Infecções por Campylobacter/microbiologia , Campylobacter jejuni/efeitos dos fármacos , Campylobacter jejuni/isolamento & purificação , Ciprofloxacina/farmacologia , Farmacorresistência Bacteriana Múltipla , Eritromicina/farmacologia , Humanos , Testes de Sensibilidade Microbiana/veterinária , Ácido Nalidíxico/farmacologia , Polimorfismo de Fragmento de RestriçãoRESUMO
The Infectious Bursal Disease (IBD) is a contagious viral disease that affects young chickens and may cause high morbidity and mortality. As the virus is very resistant to the environment, vaccination is required in case of high infection pressure. Due to variations in the virulence degree of the vaccines available to control IBD, this study aimed at evaluating the pathogenicity and immunogenicity of three types of vaccines. In total, 220 one-day-old specific pathogen free (SPF) chickens were immunized with recombinant, immune-complex and intermediate vaccines, or not vaccinated (55 birds per group) and challenged with IBD G11 strain on day 25. On days 25, 30, and 35, the Bursa of Fabricius (BF) were submitted to gross and histological examination, and serum samples were submitted to ELISA to determined anti-IBD antibody titers. On day 23, chickens were submitted to the test of hypersensitivity to phytohemagglutinin to evaluate the immunosuppressive effect of vaccines on the cell-mediated immunity. The results have indicated that the immune-complex vaccine induced the most severe BF lesions, whereas the recombinant vaccine preserved BF tissue and cell integrity. The three evaluated vaccines induced humoral immunity of similar intensity. The cellular reaction to phytohemagglutinin of the chickens immunized with recombinant and immune-complex vaccines was less severe compared with the unvaccinated chickens. In conclusion, these results indicate that the immune-complex vaccine was the most pathogenic and that all vaccines were effective in protecting SPF chickens against IBD.
Assuntos
Animais , Bursite/imunologia , Bursite/veterinária , Doenças Transmissíveis/imunologia , Doenças Transmissíveis/veterinária , Fatores de VirulênciaRESUMO
Although Pasteurella multocida is a member of the respiratory microbiota, under some circumstances, it is a primary agent of diseases , such as fowl cholera (FC), that cause significant economic losses. Experimental inoculations can be employed to evaluate the pathogenicity of strains, but the results are usually subjective and knowledge on the pathogenesis of this agent is still limited. The objective of this study was to establish a new methodology for classifying the pathogenicity of P. multocida by formulating a standard index. Strains isolated from FC cases and from swine with respiratory problems were selected. One hundred mL of a bacterial culture of each strain, containing 106 CFU, was inoculated in 10 one-day-old broilers. Mortality after inoculation, time of death (TD), and the presence of six macroscopic lesions were evaluated over a period of seven days post-inoculation (dpi). A Pathogenicity Index Per Bird (IPI), ranging 0 to 10, was calculated. Liver and heart fragments were collected to reisolate the bacteria. Blood was collected from the surviving birds, and an ELISA test was carried out to detect specific antibodies. The median of the pathogenicity indices, the number of lesions and the rate of bacteria reisolation were significantly different (p 0.05) among the origins of the isolates (p 0.05). The pathogenicity index developed in this study allows the classification of Pasteurella multocida pathogenicity and may be an alternative to the pathogenicity models currently used for screening.
Assuntos
Animais , Cólera/veterinária , Fatores de Virulência/análise , Fatores de Virulência/isolamento & purificação , Pasteurella multocida , GalinhasRESUMO
Although Pasteurella multocida is a member of the respiratory microbiota, under some circumstances, it is a primary agent of diseases , such as fowl cholera (FC), that cause significant economic losses. Experimental inoculations can be employed to evaluate the pathogenicity of strains, but the results are usually subjective and knowledge on the pathogenesis of this agent is still limited. The objective of this study was to establish a new methodology for classifying the pathogenicity of P. multocida by formulating a standard index. Strains isolated from FC cases and from swine with respiratory problems were selected. One hundred mL of a bacterial culture of each strain, containing 106 CFU, was inoculated in 10 one-day-old broilers. Mortality after inoculation, time of death (TD), and the presence of six macroscopic lesions were evaluated over a period of seven days post-inoculation (dpi). A Pathogenicity Index Per Bird (IPI), ranging 0 to 10, was calculated. Liver and heart fragments were collected to reisolate the bacteria. Blood was collected from the surviving birds, and an ELISA test was carried out to detect specific antibodies. The median of the pathogenicity indices, the number of lesions and the rate of bacteria reisolation were significantly different (p 0.05) among the origins of the isolates (p 0.05). The pathogenicity index developed in this study allows the classification of Pasteurella multocida pathogenicity and may be an alternative to the pathogenicity models currently used for screening.(AU)
Assuntos
Animais , Cólera/veterinária , Fatores de Virulência/análise , Fatores de Virulência/isolamento & purificação , Pasteurella multocida , GalinhasRESUMO
The Infectious Bursal Disease (IBD) is a contagious viral disease that affects young chickens and may cause high morbidity and mortality. As the virus is very resistant to the environment, vaccination is required in case of high infection pressure. Due to variations in the virulence degree of the vaccines available to control IBD, this study aimed at evaluating the pathogenicity and immunogenicity of three types of vaccines. In total, 220 one-day-old specific pathogen free (SPF) chickens were immunized with recombinant, immune-complex and intermediate vaccines, or not vaccinated (55 birds per group) and challenged with IBD G11 strain on day 25. On days 25, 30, and 35, the Bursa of Fabricius (BF) were submitted to gross and histological examination, and serum samples were submitted to ELISA to determined anti-IBD antibody titers. On day 23, chickens were submitted to the test of hypersensitivity to phytohemagglutinin to evaluate the immunosuppressive effect of vaccines on the cell-mediated immunity. The results have indicated that the immune-complex vaccine induced the most severe BF lesions, whereas the recombinant vaccine preserved BF tissue and cell integrity. The three evaluated vaccines induced humoral immunity of similar intensity. The cellular reaction to phytohemagglutinin of the chickens immunized with recombinant and immune-complex vaccines was less severe compared with the unvaccinated chickens. In conclusion, these results indicate that the immune-complex vaccine was the most pathogenic and that all vaccines were effective in protecting SPF chickens against IBD. (AU)
Assuntos
Animais , Doenças Transmissíveis/imunologia , Doenças Transmissíveis/veterinária , Bursite/imunologia , Bursite/veterinária , Fatores de VirulênciaRESUMO
Brazilian poultry production is very efficient and demands maximum broiler performance. Therefore, digestive system pathologies have a relevant role. Considering it is difficult to obtain consistent information on intestinal morphometric analysis, this study aimed at establishing essential and clear criteria for the collection of intestinal segments for morphometric analysis. Fifteen 13-d-old broilers were sacrificed and three intestinal segments were collected per bird. Two 3-cm long sections were obtained from each of the intestinal segments. Samples were collected open or closed. The closed samples were transversely, hemicylindrically, or longitudinally sectioned. Samples were processed and stained with hematoxylin and eosin. The number of microscopic fields in each section was counted. Villi presenting the base clearly embedded in the submucosa, no damage or folds, and simple columnar epithelium at the tip were considered adequate for measurements. These villi were counted in each sample. The results shows that hemicylindrical sections presented the highest number of observation fields, with an average of 9.76 fields. Jejunum samples were among the three highest average villi counts, with 18.23 in longitudinal sections and 15.61 in hemicylindrical sections. The results of the present study indicate that hemicylindrical sectioning and jejunal samples were, respectively, the best sectioning method and the best intestinal segment for the morphometric analysis of the intestines of broilers.(AU)
Assuntos
Animais , Aves Domésticas/anatomia & histologia , Aves Domésticas/crescimento & desenvolvimento , Intestinos/anatomia & histologiaRESUMO
Brazilian poultry production is very efficient and demands maximum broiler performance. Therefore, digestive system pathologies have a relevant role. Considering it is difficult to obtain consistent information on intestinal morphometric analysis, this study aimed at establishing essential and clear criteria for the collection of intestinal segments for morphometric analysis. Fifteen 13-d-old broilers were sacrificed and three intestinal segments were collected per bird. Two 3-cm long sections were obtained from each of the intestinal segments. Samples were collected open or closed. The closed samples were transversely, hemicylindrically, or longitudinally sectioned. Samples were processed and stained with hematoxylin and eosin. The number of microscopic fields in each section was counted. Villi presenting the base clearly embedded in the submucosa, no damage or folds, and simple columnar epithelium at the tip were considered adequate for measurements. These villi were counted in each sample. The results shows that hemicylindrical sections presented the highest number of observation fields, with an average of 9.76 fields. Jejunum samples were among the three highest average villi counts, with 18.23 in longitudinal sections and 15.61 in hemicylindrical sections. The results of the present study indicate that hemicylindrical sectioning and jejunal samples were, respectively, the best sectioning method and the best intestinal segment for the morphometric analysis of the intestines of broilers.
Assuntos
Animais , Aves Domésticas/anatomia & histologia , Aves Domésticas/crescimento & desenvolvimento , Intestinos/anatomia & histologiaRESUMO
The ability of Pasteurella multocida to invade and multiply in its host is enhanced by the presence of the capsule, one of the most important virulence factors for this bacterium. Capsular typing methods are often used in epidemiological and pathogenesis studies of this agent. Five different serogroups have been identified based on serological typing. However, such tests are laborious, and agglutination of homologous antiserum may fail. The aim of this study was to develop a multiplex PCR protocol for the identification of the hyaD-hyaC and dcbF genes specific to serogroups A and D, respectively, and to compare these results with those of phenotypic tests for 54 strains isolated from fowl cholera cases in southern Brazil. The kappa coefficient and chisquare statistics were calculated to assess the agreement between the diagnostic methods and to determine the significance of the results, respectively. The multiplex PCR was able to detect the evaluated genes. Forty-nine strains (90.74%) were classified into serogroup A, and only two isolates (3.7%) were not identified as belonging to any of the serogroups analyzed. In contrast, with the phenotypic tests, only 41 strains (75.93%) were classified into serogroup A and 11 samples (20.37%) were unidentifiable. Of the strains analyzed, 70.37% were classified into the same serogroup (A) by both methods, and the kappa coefficient (k = 0.017) indicated poor agreement between the tests. Thus, multiplex PCR is an alternative for P. multocida capsular typing, as it allows the simultaneous and rapid detection of genes and also provides a greater strain-typing capacity.(AU)
Assuntos
Animais , Pasteurella multocida/isolamento & purificação , Pasteurella multocida/patogenicidade , Cápsulas Bacterianas , Aves/microbiologia , Reação em Cadeia da Polimerase Multiplex/métodos , Reação em Cadeia da Polimerase Multiplex/veterinária , Técnicas de Tipagem Bacteriana/métodosRESUMO
The ability of Pasteurella multocida to invade and multiply in its host is enhanced by the presence of the capsule, one of the most important virulence factors for this bacterium. Capsular typing methods are often used in epidemiological and pathogenesis studies of this agent. Five different serogroups have been identified based on serological typing. However, such tests are laborious, and agglutination of homologous antiserum may fail. The aim of this study was to develop a multiplex PCR protocol for the identification of the hyaD-hyaC and dcbF genes specific to serogroups A and D, respectively, and to compare these results with those of phenotypic tests for 54 strains isolated from fowl cholera cases in southern Brazil. The kappa coefficient and chisquare statistics were calculated to assess the agreement between the diagnostic methods and to determine the significance of the results, respectively. The multiplex PCR was able to detect the evaluated genes. Forty-nine strains (90.74%) were classified into serogroup A, and only two isolates (3.7%) were not identified as belonging to any of the serogroups analyzed. In contrast, with the phenotypic tests, only 41 strains (75.93%) were classified into serogroup A and 11 samples (20.37%) were unidentifiable. Of the strains analyzed, 70.37% were classified into the same serogroup (A) by both methods, and the kappa coefficient (k = 0.017) indicated poor agreement between the tests. Thus, multiplex PCR is an alternative for P. multocida capsular typing, as it allows the simultaneous and rapid detection of genes and also provides a greater strain-typing capacity.