Efeitos in vitro de ocratoxina A, deoxinivalenol e zearalenona sobre a viabilidade celular e atividade de E-ADA em linfócitos de frangos de corte / In vitro effects of ochratoxin A, deoxynivalenol and zearalenone on cell viability and E-ADA activity in broiler chickens lymphocytes

Mycotoxins are a group of chemically diverse naturally occurring substances resulting from the secondary metabolism of pathogenic filamentous fungi. They are produced mainly by the genera Fusarium, Alternaria, Aspergillus and Penicillium which can contaminate grains and cereals such as wheat, corn and soy. According to the nature and the concentration levels, mycotoxins can induce toxic effects in food-production animals and humans. An in vitro study was conducted to evaluate the susceptibility of broiler chickens lymphocytes to different concentrations of ochratoxin A, deoxynivalenol and zearalenone. Each toxin was added to the cell medium at different concentrations (0.001, 0.01, 0.1 and 1μg/mL). Cell viability and ecto-adenosine deaminase activity were assessed at 24, 48 and 72 hours by colorimetric assays. Thus, it were used 0.7x10(5) lymphocytes/mL in RPMI 1640 medium, supplemented with 10% fetal bovine serum and 2.5 IU of penicillin/streptomycin per mL, incubated at 37°C in a 5% CO2 atmosphere. All the experiments were carried out in triplicate and the results were expressed as mean ± standard error of the mean. The results showed that OTA and DON induced lymphocyte proliferation and reduced enzymatic activity in vitro (P<0,05), whereas ZEA also promoted proliferation (P<0,05), but neither alteration on enzymatic activity (P>0,05). It was possible to correlate the results about viability cell and ecto-adenosine deaminase activity, suggesting that, at minimal concentrations, the evaluated mycotoxins do not stimulated the enzymatic activity, which has proinflammatory action and contributes for the immunosuppression process, thus, avoiding a decrease on the viability cell. This is the first in vitro study conducted with OTA, DON and ZON in broiler chickens lymphocytes evaluating these parameters.

Micotoxinas representam um vasto grupo de contaminantes químicos naturais originados a partir do metabolismo secundário de fungos filamentosos patogênicos. Elas são produzidas, principalmente, pelos gêneros Fusarium, Alternaria, Aspergillus e Penicillium, os quais podem contaminar grãos e cereais, como trigo, milho e soja. Conforme sua natureza e níveis de concentração, micotoxinas podem induzir efeitos tóxicos em animais de produção e humanos. Um estudo in vitro foi realizado para avaliar a susceptibilidade das células linfocitárias de frangos de corte a diferentes concentrações de ocratoxina A, deoxinivalenol e zearalenona. Cada micotoxina foi adicionada ao meio celular em diferentes concentrações (0,001; 0,01; 0,1 e 1μg/mL). A viabilidade celular e atividade de ecto-adenosina desaminase foram analisadas em 24, 48 e 72 horas através de ensaios colorimétricos. Para isso, foram utilizados 0,7x10(5) linfócitos/mL em meio RPMI 1640, suplementado com 10% de soro fetal bovino e 2,5 UI de penicilina/estreptomicina por mL, incubados em atmosfera de 5% de CO2 a 37 °C. Todos os experimentos foram realizados em triplicata e os resultados foram expressos como média e erro padrão da média. Os resultados obtidos demonstraram que tanto ocratoxina A como deoxinivalenol induziram proliferação linfocitária e baixa atividade enzimática in vitro (P<0,05), enquanto zearalenona também induziu proliferação (P<0,05), mas nenhuma alteração na atividade enzimática (P>0,05). Foi possível correlacionar os dados referentes à viabilidade celular e atividade de ecto-adenosina desaminase, sugerindo que, em concentrações mínimas, as micotoxinas testadas não estimularam a atividade da enzima, que possui ação pró-inflamatória e contribui para o processo de imunossupressão e, portanto, evitando um decréscimo na viabilidade celular. Este é o primeiro estudo feito com OCRA, DON e ZEA sobre linfócitos de frangos de corte em cultivos in vitro na avaliação desses parâmetros.

Isolation and identification of feline calicivirus and feline herpesvirus in Southern Brazil

Feline calicivirus (FCV) and feline herpesvirus type 1 (FHV-1) are the two primary causes of upper respiratory tract disease in cats. The aim of this study was to demonstrate the distribution of FCV and FHV-1 among the feline population of several counties in Rio Grande do Sul State, Brazil. To this end, conjunctival and nasal swabs were collected from 302 cats from different locations, including households, breeding catteries, veterinary clinics, animal hospitals and experimental research facilities. The samples were collected between July 2006 to June 2009. The virus isolation was performed in CRFK cells and, subsequently, the identification was confirmed by PCR. FCV, FHV-1, or both were isolated from 55 cats from 28 different locations. FCV alone was isolated from 52.7% (29/55) of the animals that tested positively, FHV-1 alone was isolated from 38.2% (21/55) of the animals that tested positively, and co-infection were detected in 9.1% (5/55) of the animals that tested positively. Virus detection was more prevalent in cats that were less than 1 year old, among animals that shared a living space with other cats, and females. FCV and FHV-1 were isolated from vaccinated cats. In addition, both viruses were isolated from cats that showed no signs of disease. The results suggest that a carrier state is common for both viruses in the evaluated population. A search for other causes of respiratory disease in that population is necessary; and further studies relating to the molecular characterization of viruses and vaccine efficacy are also necessary.