Portal de Pesquisa da BVS Veterinária

Tese em Português | VETTESES | ID: vtt-202479

Resumo

O Porcine circovirus 2 é o principal agente etiológico das doenças associadas ao circovírus (PCVADs). Responsável por grandes prejuízos na suinocultura nacional e mundial visto o grau de endemia observado nas granjas. Atualmente, o controle das PCVADs é feito com cuidados no manejo e uso de vacinas recombinantes provenientes de empresas multinacionais. Alguns testes já foram conduzidos com a vacina avaliada neste estudo e indicaram imunogenicidade. Objetivou-se com esse trabalho a padronização e otimização da técnica de qPCR para detecção de PCV2 em soro de animais e a realização de teste experimental, com infecção natural, usando diferentes formulações vacinais visando à comparação entre os grupos quanto à média da carga viral sérica. Como método de avaliação usou-se a técnica de qPCR para quantificação viral em amostras de soro de animais provenientes dos grupos vacinados. Os ensaios realizados para padronização da técnica se mostraram eficazes quando se usou amostras provenientes da curva padrão e amostras de soro de animais virêmicos, o grupo vacinado com a formulação F3 foi o único em que não foi observado aumento na carga viral sérica.

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The intensive use of pesticides in agriculture has caused contamination of aquatic environments. Diflubenzuron (Dimilin ® ) is a widely used insecticide for agricultural areas in combating insect pests, and has been frequently used in fish farms due to its effectiveness in the control of fish ectoparasites. The indiscriminate use of this pesticide in pisciculture can result in toxicity causing fish health problems. The aim of this study to discriminate the possible influence of sex of the fish in response to the action of Dimilin ® , to determine whether sublethal exposure to this pesticide causes changes in the morphology of the gills of male and female Hyphessobrycon eques. The fish were exposed to concentrations of 0.01, 0.1 and 1.0 mg.L -1 Dimilin ® for 96 hours and 17 days. In the 96 hour experiment a single application of toxic in water was carried out and in the 17 days experiment two applications were performed, one one the first day and another on the fourth day of the experiment. At the end of the experiment, gill tissue samples of 10 animals from each group were collected and processed for histological study. Morphometric and histopathological findings in 10 fields per animal were analyzed. Analysis of the water showed in to be in accordance with the conditions for cultivation and creation of tropical fish. Histological changes were found in the gills of male and female Hyphessobrycon eques. Histologic and morphometric analyses showed significant differences (P<0.05) between the concentrations within the same experiment in the same sex. The histopathological alteration index (HAI), in both males and females was greater at higher concentrations (0.1 and 1.0 mg.L -1 ) in the 96 hours and 17 days experiments, indicating differences in comparison with the control group and between the concentrations within the same experiment. The mean alteration value (MAV) was higher in all groups exposed to Dimilin ® in exposure times of 96 hours and 17 days compared to the control group. The HAI, the MAV and the morphometric analysis did not show a specific reaction of sex, indicating that the gills of males and females do not respond differently (P>0.05) after exposure to sublethal concentrations of insecticide Dimilin ® . The results showed that even at lower concentrations the insecticide caused mild to moderate morphological changes in the gills of males and females, compromising tissue function. So, Hyphessonbrycon eques can be considered bioindicator of environmental contamination by Dimilin ® and be used as a model in toxicological tests and environmental assessments.

Biblioteca responsável: BR68.1