Avaliação da imunidade materna na progênie de reprodutoras pesadas vacinadas com um candidato vacinal recombinante contra Salmonella Enteritidis.
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Data
2020-07-28
Autores
Yamawaki, Roberto Alexandre
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Universidade Estadual Paulista (Unesp)
Resumo
Salmonella enterica subsp. enterica serovar Enteritidis (SE) é o principal agente de doenças transmitidas por alimentos (DTA) em seres humanos. Vacinação apresenta-se como uma das ferramentas mais utilizadas para prevenir a colonização e infecção por SE em aves. O presente estudo avaliou a eficácia de um candidato vacinal recombinante contra SE. Trinta aves matrizes pesadas e cinco aves machos com 10 semanas e status Salmonella-free foram alojadas e divididos em 3 grupos: não vacinado (NV), vacinado com candidato vacinal recombinante (VAC) e vacinado com bacterina comercial (BAC). Amostras de soro e ovos embrionados foram colhidos em dois períodos após a dose booster, para quantificação da taxa de transferência de IgY para os ovos e a progênie. Quarenta pintos de um dia da progênie foram divididos em dois grupos, NV e VAC, e desafiados com 107 UFC de SE no segundo dia de vida. Soro, fragmentos de intestino e fígado e conteúdo cecal foram colhidos em cada grupo. Os níveis de IgY foram significativamente maiores no grupo VAC comparado com o NV em todos os períodos no soro e gema de ovos embrionados de matrizes pesadas e no soro das progênies, sendo as taxas de transferências de IgY maiores no grupo VAC comparado com grupo BAC. Foram encontradas maiores relações vilo-cripta no duodeno, jejuno e íleo a 4 dpi na progênie do grupo VAC. Foi utilizado uma elevada dose desafio de SE (107 UFC/pinto), no entanto, apesar da forte resposta imune, não houve diferença estatística na recuperação de SE no conteúdo cecal das progênies. Assim, outros estudos sobre a capacidade de estímulo a resposta imune mediada por células, a proteção a diferentes doses desafio e capacidade de proteção direta na ave vacinada, auxiliarão na elaboração dessa vacina.
Salmonella enterica subsp. enterica serovar Enteritidis (SE) is the main cause of foodborne diseases (FBD) in humans. Vaccination is one of the most used tools to prevent colonization and infection by SE in birds. The present study evaluated the effectiveness of a candidate for SE recombinant vaccine. Thirty broiler breeders and five roosters with 10 weeks age and Salmonella-free status were housed and divided into 3 groups: unvaccinated (UV), vaccinated with recombinant vaccine candidate (VAC) and vaccinated with commercial bacterin (BAC). Samples of serum and embryonated eggs were collected 7 and 12 weeks after the booster dose, to quantify the transfer rate of IgY to the eggs and the progeny. Forty day-old progeny chicks were divided into two groups, UV and VAC, and challenged with 107 CFU of SE on the second day of life. Serum, fragments of intestine and liver and cecal content were collected in each group. The IgY levels were significantly higher in the VAC group compared to the UV in all periods in the egg yolk and broiler breeders’ serum and in the progeny’s serum, with the IgY transfer rates being higher in the VAC group compared to the BAC group. Greater vilo-crypt ratio were found in the duodenum, jejunum and ileum at 4 dpi in the progeny of the VAC group. A high challenge dose of SE (107 CFU / chick) was used, however, despite the strong immune response, there were no statistical difference in the recovery of SE in the progenies’ cecal contents. Thus, more studies on the ability to stimulate the cell-mediated immune response, the protection at different challenge doses and the ability to directly protect the vaccinated poultry will assist in the development of this vaccine.
Salmonella enterica subsp. enterica serovar Enteritidis (SE) is the main cause of foodborne diseases (FBD) in humans. Vaccination is one of the most used tools to prevent colonization and infection by SE in birds. The present study evaluated the effectiveness of a candidate for SE recombinant vaccine. Thirty broiler breeders and five roosters with 10 weeks age and Salmonella-free status were housed and divided into 3 groups: unvaccinated (UV), vaccinated with recombinant vaccine candidate (VAC) and vaccinated with commercial bacterin (BAC). Samples of serum and embryonated eggs were collected 7 and 12 weeks after the booster dose, to quantify the transfer rate of IgY to the eggs and the progeny. Forty day-old progeny chicks were divided into two groups, UV and VAC, and challenged with 107 CFU of SE on the second day of life. Serum, fragments of intestine and liver and cecal content were collected in each group. The IgY levels were significantly higher in the VAC group compared to the UV in all periods in the egg yolk and broiler breeders’ serum and in the progeny’s serum, with the IgY transfer rates being higher in the VAC group compared to the BAC group. Greater vilo-crypt ratio were found in the duodenum, jejunum and ileum at 4 dpi in the progeny of the VAC group. A high challenge dose of SE (107 CFU / chick) was used, however, despite the strong immune response, there were no statistical difference in the recovery of SE in the progenies’ cecal contents. Thus, more studies on the ability to stimulate the cell-mediated immune response, the protection at different challenge doses and the ability to directly protect the vaccinated poultry will assist in the development of this vaccine.
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Palavras-chave
Salmonella Enteritidis, Imunidade humoral, Morfologia intestinal, Progênie, Vacina recombinante, Humoral immunity, Intestinal morphology, Progeny, Recombinant vaccine