RESUMO

BACKGROUND: Antarctic notothenioids are an impressive adaptive radiation. While they share recent common ancestry with several species-depauperate lineages that exhibit a relictual distribution in areas peripheral to the Southern Ocean, an understanding of their evolutionary origins and biogeographic history is limited as the sister lineage of notothenioids remains unidentified. The phylogenetic placement of notothenioids among major lineages of perciform fishes, which include sculpins, rockfishes, sticklebacks, eelpouts, scorpionfishes, perches, groupers and soapfishes, remains unresolved. We investigate the phylogenetic position of notothenioids using DNA sequences of 10 protein coding nuclear genes sampled from more than 650 percomorph species. The biogeographic history of notothenioids is reconstructed using a maximum likelihood method that integrates phylogenetic relationships, estimated divergence times, geographic distributions and paleogeographic history. RESULTS: Percophis brasiliensis is resolved, with strong node support, as the notothenioid sister lineage. The species is endemic to the subtropical and temperate Atlantic coast of southern South America. Biogeographic reconstructions imply the initial diversification of notothenioids involved the western portion of the East Gondwanan Weddellian Province. The geographic disjunctions among the major lineages of notothenioids show biogeographic and temporal correspondence with the fragmentation of East Gondwana. CONCLUSIONS: The phylogenetic resolution of Percophis requires a change in the classification of percomorph fishes and provides evidence for a western Weddellian origin of notothenioids. The biogeographic reconstruction highlights the importance of the geographic and climatic isolation of Antarctica in driving the radiation of cold-adapted notothenioids.

Assuntos

Perciformes/classificação , Perciformes/genética , Animais , Regiões Antárticas , Evolução Molecular , Proteínas de Peixes/genética , Funções Verossimilhança , Perciformes/anatomia & histologia , Filogenia , América do Sul

RESUMO

Several studies point out that eggs are the main cause of human salmonellosis, particularly when poorly processed or eaten raw. In addition of causing public health problems, the presence of Salmonella hinders international food trade, and therefore, it is a health barrier. There are several predisposing factors for the contamination of internal egg content by Salmonella spp, including eggshell quality, which is related to dietary calcium (Ca) and phosphorus (P) levels. In this study, eggs from Japanese quails fed diets containing two different Ca (2.0 or 3.5%) or P (0.25 or 0.45%) levels were evaluated. Three production phases were used in the experiment: starter, intermediate, and final. The presence of Salmonella Enteriditis in the eggshell and internal content in in the periods of 0, 24, 96, and 168 hours after the experimental contamination of the eggs by immersion in broth containing Salmonella Enteriditis. The bacterium was detected in decreasing numbers in the eggshell of eggs from all treatments and during all storage periods. No significant bacterial numbers were found in the internal egg content in none of the treatments during none of the production phases. Therefore, the evaluated Ca and P levels in the diet of Japanese quails did not result in higher or lower public health risk relative to the presence of Salmonella Enteritidis in the internal egg content.

Assuntos

Animais , Coturnix/microbiologia , Cálcio da Dieta , Fósforo na Dieta , Salmonella enteritidis

RESUMO

Several studies point out that eggs are the main cause of human salmonellosis, particularly when poorly processed or eaten raw. In addition of causing public health problems, the presence of Salmonella hinders international food trade, and therefore, it is a health barrier. There are several predisposing factors for the contamination of internal egg content by Salmonella spp, including eggshell quality, which is related to dietary calcium (Ca) and phosphorus (P) levels. In this study, eggs from Japanese quails fed diets containing two different Ca (2.0 or 3.5%) or P (0.25 or 0.45%) levels were evaluated. Three production phases were used in the experiment: starter, intermediate, and final. The presence of Salmonella Enteriditis in the eggshell and internal content in in the periods of 0, 24, 96, and 168 hours after the experimental contamination of the eggs by immersion in broth containing Salmonella Enteriditis. The bacterium was detected in decreasing numbers in the eggshell of eggs from all treatments and during all storage periods. No significant bacterial numbers were found in the internal egg content in none of the treatments during none of the production phases. Therefore, the evaluated Ca and P levels in the diet of Japanese quails did not result in higher or lower public health risk relative to the presence of Salmonella Enteritidis in the internal egg content.(AU)

Assuntos

Animais , Coturnix/microbiologia , Salmonella enteritidis , Cálcio da Dieta , Fósforo na Dieta

RESUMO

Several studies point out that eggs are the main cause of human salmonellosis, particularly when poorly processed or eaten raw. In addition of causing public health problems, the presence of Salmonella hinders international food trade, and therefore, it is a health barrier. There are several predisposing factors for the contamination of internal egg content by Salmonella spp, including eggshell quality, which is related to dietary calcium (Ca) and phosphorus (P) levels. In this study, eggs from Japanese quails fed diets containing two different Ca (2.0 or 3.5%) or P (0.25 or 0.45%) levels were evaluated. Three production phases were used in the experiment: starter, intermediate, and final. The presence of Salmonella Enteriditis in the eggshell and internal content in in the periods of 0, 24, 96, and 168 hours after the experimental contamination of the eggs by immersion in broth containing Salmonella Enteriditis. The bacterium was detected in decreasing numbers in the eggshell of eggs from all treatments and during all storage periods. No significant bacterial numbers were found in the internal egg content in none of the treatments during none of the production phases. Therefore, the evaluated Ca and P levels in the diet of Japanese quails did not result in higher or lower public health risk relative to the presence of Salmonella Enteritidis in the internal egg content.