RESUMO
Nicarbazin (NCZ) is a worldwide used anticoccidial in poultry farming to avoid coccidiosis disease when chickens are reared on conventional poultry litter. If proper dosage and withdrawal time are not followed, the component dinitrocarbanilide (DNC) of NCZ may be present in chicken tissues, therefore posing a risk to consumers if the residues are above 200 µg/kg. Litter reuse is a common and important practice in commercial chicken production. Literature is lacking about the influence of litter reuse on DNC deposition in chicken tissues and its impact on food safety. We aimed to evaluate DNC residues in breast and liver by LC-MS/MS from broilers from an experiment with 10 consecutive flocks during 2 years. The experiment included three treatments containing NCZ in the diet (T1 = 125 mg/kg, 1−21 d; T2 = 125 mg/kg, 1−32 d; T3 = 40 mg/kg, 1−32 d). DNC residues in chicken breast at 21 d in T1 ranged from 648.8−926 µg/kg, at 32 d in T2 and T3 varied, respectively, from 232−667 µg/kg and 52−189 µg/kg. Regarding liver, DNC residues at 21 days in T1 ranged from 11,754−15,281 µg/kg, at 32 days in T2 and T3 varied, respectively, from 10,168−15,021 µg/kg and 2899−4573 µg/kg. When NCZ was withdrawn from feed, DNC residues dropped to
RESUMO
As part of an epidemiological study of infectious bronchitis virus (IBV) in Brazil, 252 samples from IBV-suspect flocks were tested and the IBV-positive samples were analysed by sequencing of hypervariable regions 1 and 2 of the S1 gene. A high prevalence of IBV variants was found and the sequence analysis of 41 samples revealed a high molecular similarity among the Brazilian isolates (from 90.2 to 100% and from 85.3 to 100% nucleotide and amino acid identity, respectively). The Brazilian isolates showed low genetic relationship with Massachusetts (63.4 to 70.7%), European (45.9 to 75.6%), American (49.3 to 76.4%) and other reference serotypes (67.5 to 78.8%). The Brazilian isolates branched into one unique cluster, separate from the reference serotypes used for infectious bronchitis control in other countries. The variants analysed in this work had a high similarity with all previously published Brazilian IBV isolates, suggesting the presence and high prevalence of a unique or predominant genotype circulating in Brazil. In addition, the virus neutralization test showed that the three Brazilian isolates analysed in the present study are antigenically related to one another but are different from the Massachusetts serotype. The present study shows that IBVs of a unique genotype can be associated with different clinical diseases, and that low genetic variation was detected in this genotype over a long period of time. The molecular characterization of the Brazilian variants isolated from 2003 to 2009 from different geographic regions of the country shows that only one predominant genotype is widespread in the Brazilian territory, denominated in this study as BR-I genotype.
Assuntos
Galinhas/virologia , Infecções por Coronavirus/veterinária , Vírus da Bronquite Infecciosa/isolamento & purificação , Doenças das Aves Domésticas/epidemiologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Brasil/epidemiologia , Embrião de Galinha , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Feminino , Variação Genética , Genótipo , Vírus da Bronquite Infecciosa/classificação , Vírus da Bronquite Infecciosa/genética , Masculino , Epidemiologia Molecular , Dados de Sequência Molecular , Filogenia , Doenças das Aves Domésticas/virologia , Prevalência , Análise de Sequência de DNA , Organismos Livres de Patógenos Específicos , Fatores de TempoRESUMO
A comparative survey between non-systemic (paratyphoid Salmonellae) and systemic (S. Pullorum and S. Gallinarum) Salmonella strains was performed to produce a virulence gene profile for differentiation among the groups. The following virulence genes were evaluated: invA, spvC, sefC, pefA, fimY, sopB, sopE1, stn and avrA. There are substantial differences among paratyphoid Salmonellae, S. Pullorum, and S. Gallinarum regarding the genes sefC, spvC, sopE1 and avrA. A higher frequency of sefC, spvC, sopE1 and avrA genes were detected in S. Gallinarum and S. Pullorum when compared with strains from the paratyphoid group of Salmonella. These results may be useful for differentiating among different groups and serotypes.(AU)
Uma investigação comparativa entre amostras de Salmonella não-sistêmicas (grupo paratifoide) e sistêmicas (S. Pullorum and S. Gallinarum) foi desenvolvida para produzir um perfil de genes de virulência para diferenciação entre os grupos. Os seguintes genes de virulência foram avaliados invA, spvC, sefC, pefA, fimY, sopB, sopE1, stn e avrA. Detectou-se uma diferença substancial entre Salmonella do grupo paratifoide, S. Pullorum e S. Gallinarum considerando os genes sefC, spvC, sopE1 e avrA. Os genes sefC, spvC, sopE1 e avrA foram detectados, em maior número, em S. Gallinarum e S. Pullorum quando comparados com as amostras de Salmonella do grupo paratifoide. Estes resultados podem ser úteis para a diferenciação entre os diferentes grupos e sorotipos de Salmonella.(AU)
Assuntos
Animais , Doenças das Aves Domésticas/microbiologia , Salmonella/genética , Salmonella/patogenicidade , GalinhasRESUMO
Enteric disease is a multifactorial problem in chickens, which causes gastrointestinal alterations, elevated feed conversions and impairment. In the last years, several enteric viruses were implicated in enteric disease; case reports have shown their presence alone or in concomitant infections during outbreaks and have suggested that they might be determining factors in the aetiology of enteric disease. This study shows high detection rates of enteric viruses in the pancreas and spleen in samples from an outbreak of enteritis and malabsorption in 16 chicken flocks (n=80 broilers). Avian nephritis virus (ANV) was the most ubiquitous virus, present in 75% of the flocks followed by avian rotavirus group A (ART-A) with 68.75%, and by chicken astrovirus (CAstV) and chicken parvovirus (ChPV) in 43.75% of samples. Viruses were present in the pancreas of positive flocks at extremely high rates: 100% for ART-A, 91.7% for ANV, 100% for CAstV and 57.14% for ChPV. By contrast, only 16.7% and 57.14% of intestine samples were positive for ANV and CAstV, respectively. Avian reovirus (AReo) and avian adenovirus group 1 (FAdV-1) were not detected. These results suggest that high viral detection rates in pancreas samples may be a result of viremia during enteric disease, with subsequent damage of the exocrine pancreas, leading to runting-stunting syndrome (RSS).(AU)
A doença entérica é um problema multifatorial em galinhas que causa alterações gastrointestinais, conversão alimentar elevada e deficiência de crescimento. Nos últimos anos, os vírus entéricos foram associados à doença entérica; casos reportados mostraram a infecção de um único vírus e também infecções concomitantes durante os surtos sugerindo a presença de múltiplos fatores etiológicos nas doenças entéricas. Este estudo mostra uma alta taxa de detecção dos vírus entéricos em amostras de pâncreas e baço de um surto de enterite e má-absorção em 16 lotes de frangos (n=80 frangos). O vírus de nefrite aviária (ANV) foi o vírus mais detectado, estando presente em 75% dos lotes seguido pelo rotavírus aviário grupo A (ART-A) em 68,75% dos casos, e pelo astrovirus (CAstV) e parvovírus aviários (ChPV), ambos em 43,75% das amostras. Os vírus estavam presentes no pâncreas dos lotes positivos em percentuais elevados: 100% para ART-A e CAstV; 91,7% para ANV, e em 57,14% para ChPV. Em contraste, somente 16,7% e 57,14%, em amostras de intestino, foram positivos para ANV e CAstV, respectivamente. Reovírus aviário (AReo) e o adenovírus do grupo 1 (FAdV-1) não foram detectados. Estes resultados sugerem que os elevados percentuais de vírus detectados em amostras de pâncreas podem estar associados à viremia durante a doença entérica, com subsequente lesão no pâncreas exócrino das aves levando ao desenvolvimento da síndrome de nanismo e raquitismo.(AU)