Vacina bivalente contra infecção por Aeromonas sobria e Streptococcus agalactiae em tilápias-do-Nilo (Oreochromis niloticus) do Oeste do Paraná, Brasil.
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Data
2020-04-02
Autores
Rivas, Açucena Veleh
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Resumo
O Brasil é um dos maiores produtores de tilápia (Oreochromis niloticus, Linnaeus 1758) do mundo, entretanto, um dos principais fatores que limitam essa produção é a ocorrência de infecções causadas por Aeromonas spp. e Streptococcus spp. Este trabalho teve como objetivo avaliar uma vacina bivalente contra Aeromonas sobria e Streptococcus agalactiae por administração intraperitoneal (i.p.) em tilápias-do-Nilo provenientes de tanques de produção, sob condições experimentais. Foram selecionados 92 peixes (50g) de tanques comerciais para o experimento, as bactérias foram isoladas e identificadas a partir de peixes com sinais clínicos de bacterioses. Ambas culturas de bactérias foram inativadas e ajustadas para 1 × 107 células / dose. Os grupos controle (46) e vacinado (46) receberam via i.p. 50μL de solução salina estéril (NaCl 0,9%) e 50μL da vacina, respectivamente. O teste de aglutinação foi realizado após 30 dias da imunização. A infecção experimental foi realizada com 1 x 108 células / dose via i.p. de ambas as bactérias após 30 dias de vacinação. Na análise estatística foram realizados o teste de qui-quadrado (corrigido de Yates), o cálculo de Risco Relativo (RR), a Porcentagem Relativa de Sobrevivência (RPS), o teste de Mann-Whitney, o teste de Log-rank (Curvas de Sobrevivência) e o teste T de Student. Fragmentos de pele, fígado e baço foram coletados de peixes de cada grupo experimental, acondicionados em paraformaldeído e submetidos ao processamento típico para cortes histológicos e analisados quanto às alterações estruturais e celulares. Os testes de aglutinação mostraram atividade aglutinante com soros de peixes vacinados para os antígenos de ambas as bactérias nas três diluições testadas. Os resultados de eficácia foram p = 0,0042, RR = 0,13 (IC 95%: 0,02-0,75) e RPS = 91%. A mortalidade no grupo vacinado foi de 01 (2,94%) e no grupo controle foi de 11 (32,35%). A vacina impediu sinais clínicos das doenças no grupo vacinado. O grupo controle mostrou sinais clínicos clássicos das doenças. As alterações histológicas dos órgãos analisados dos grupos vacinado e controle não apresentaram diferenças significativas. A vacina bivalente testada protegeu a tilápia contra infecções em condições experimentais.
Brazil is one of the largest tilapias(Oreochromis niloticus, Linnaeus 1758) producers in the world, however, one of the main factors that limit this production is the occurrence of infections caused by Aeromonas spp. and Streptococcusspp. This work aimed to evaluate a bivalent vaccine against AeromonassobriaandStreptococcusagalactiaeby intraperitoneal (i.p.) administration in Nile tilapia from production tanks, under experimental conditions. 92 fish (50g) were selected from commercial tanks for the experiment,andthe bacteria were isolated and identified from fish with clinical signs of bacteriosis. Both cultures of bacteria were inactivated and adjusted to 1 × 107cells / dose. The control (46) and vaccinated (46) groups received via i.p. 50μL of sterile saline solution (NaCl 0.9%) and 50μL of the vaccine, respectively. The agglutination test was performed 30 days after immunization. The experimental infection was performed with 1x 108cells / dose via i.p. of both bacteria after 30 days of vaccination. In the statistical analysis, the chi-square test (corrected by Yates), the calculation of Relative Risk (RR), the Relative Percentage of Survival (RPS), the Mann-Whitney test, the Log-rank test (Survival Curves) and Student's t testwere performed. Skin, liver and spleen fragments were collected from fish fromeach experimental group, stored in paraformaldehyde and subjected to typical processing for histological cuts and analyzed for structural and cellular changes. The agglutination tests showed agglutinating activity with vaccinated fish sera for the antigens of both bacteria in the three dilutions tested. The efficacy results were p = 0.0042, RR = 0.13 (95% CI: 0.02-0.75) and RPS= 91%. Mortality in the vaccinated group was 01 (2.94%) and in the control group it was 11 (32.35%). The vaccine prevented clinical signs of disease in the vaccinated group. The control group showed classic clinical signs of the diseases. The histologicalchanges in the organs analyzed in the vaccinated and control groups did not show significant differences. The tested bivalent vaccine protected tilapia against infections under experimental conditions.
Brazil is one of the largest tilapias(Oreochromis niloticus, Linnaeus 1758) producers in the world, however, one of the main factors that limit this production is the occurrence of infections caused by Aeromonas spp. and Streptococcusspp. This work aimed to evaluate a bivalent vaccine against AeromonassobriaandStreptococcusagalactiaeby intraperitoneal (i.p.) administration in Nile tilapia from production tanks, under experimental conditions. 92 fish (50g) were selected from commercial tanks for the experiment,andthe bacteria were isolated and identified from fish with clinical signs of bacteriosis. Both cultures of bacteria were inactivated and adjusted to 1 × 107cells / dose. The control (46) and vaccinated (46) groups received via i.p. 50μL of sterile saline solution (NaCl 0.9%) and 50μL of the vaccine, respectively. The agglutination test was performed 30 days after immunization. The experimental infection was performed with 1x 108cells / dose via i.p. of both bacteria after 30 days of vaccination. In the statistical analysis, the chi-square test (corrected by Yates), the calculation of Relative Risk (RR), the Relative Percentage of Survival (RPS), the Mann-Whitney test, the Log-rank test (Survival Curves) and Student's t testwere performed. Skin, liver and spleen fragments were collected from fish fromeach experimental group, stored in paraformaldehyde and subjected to typical processing for histological cuts and analyzed for structural and cellular changes. The agglutination tests showed agglutinating activity with vaccinated fish sera for the antigens of both bacteria in the three dilutions tested. The efficacy results were p = 0.0042, RR = 0.13 (95% CI: 0.02-0.75) and RPS= 91%. Mortality in the vaccinated group was 01 (2.94%) and in the control group it was 11 (32.35%). The vaccine prevented clinical signs of disease in the vaccinated group. The control group showed classic clinical signs of the diseases. The histologicalchanges in the organs analyzed in the vaccinated and control groups did not show significant differences. The tested bivalent vaccine protected tilapia against infections under experimental conditions.
Abstract
Descrição
Dissertação de mestrado apresentada ao Programa de Pós-Graduaçãoem Biociências, do Instituto Latino-Americano de Ciências da Vida e da Natureza, da Universidade Federal da Integração Latino-Americana, como requisito parcial à obtenção do título de Mestre em Ciências, área de concentração Biociências.Orientador: Prof. Dr. Kelvinson Fernandes Viana
Palavras-chave
Aquicultura, Imunoproteção, Bacterioses, Peixes
Citação
RIVAS, Açucena Veleh. Vacina bivalente contra infecção por Aeromonas sobriae Streptococcus agalactiaeem tilápias-do-Nilo (Oreochromis niloticus) do Oeste do Paraná, Brasil. 2020. 57 p. Dissertação de mestrado (Programa de Pós-Graduação em Biociências) – Universidade Federal da Integração Latino-Americana, Foz do Iguaçu, 2020.