Metabolic alterations in broiler chickens experimentally infected with sporulated oocysts of Eimeria maxima / Alterações metabólicas em frangos de corte infectados experimentalmente com oocistos esporulados de Eimeria maxima

Metabolic and morphometric alterations of the duodenal villi caused by parasitism of chickens by Eimeria maxima were evaluated, using 100 male Cobb birds, randomly distributed into two groups (control and infected). The infected group was inoculated with 0.5 ml of a solution containing 5×103 sporulated oocysts of Eimeria maxima. Ten birds per sample were sacrificed on the 6th, 11th, 22nd and 41st days post-infection (dpi). In order to evaluate the alterations, samples of duodenum, jejunum and ileum fragments were collected after necropsy for histological analysis. Villus biometry was determined by means of a slide graduated in microns that was attached to a binocular microscope. To evaluate the biochemical data, 5 ml of blood were sampled from the birds before sacrifice. The statistical analyses were performed using the GraphPad 5 statistical software for Windows. Tukey's multiple comparison test (p <0.05) was performed for the different dpi's and the unpaired t test for the difference between the groups. Infection by E. maxima causes both qualitative and quantitative alterations to the structure of the intestinal villi, thereby interfering with the absorption of nutrients such as calcium, phosphorus, magnesium, protein and lipids, with consequent reductions in the birds' weights.

Foram avaliadas alterações metabólicas e morfométricas das vilosidades intestinais causadas pelo parasitismo de frangos por Eimeria maxima, sendo utilizadas 100 aves da linhagem Coob, machos, distribuídos aleatoriamente em dois grupos experimentais: grupo controle, inoculado com 0,5 ml de água destilada; grupo infectado, inoculado com 0,5ml de solução contendo 5×103 oocistos esporulados de Eimeria maxima. Foram sacrificadas 10 aves por coleta no 0, 6, 11, 22 e 41 dias pós-infecção. Para avaliar as alterações foram retiradas, após necropsia, amostras de fragmentos do duodeno, jejuno e íleo para análise histológica. A determinação da biometria de vilosidades foi realizada por meio de lâmina milimetrada acoplada a um microscópio binocular. Para avaliação dos dados bioquímicos foram coletados 5 ml de sangue das aves antes da eutanásia. As análises estatísticas foram realizadas, utilizando-se o programa estatístico Graphpad Prism. 5 – Windows e realizado o teste de comparações múltiplas de Tukey (p <0,05) para os diferentes dpi's e o Teste T não Pareado para diferença entre os grupos. A infecção por E. maxima provoca alterações qualitativas e quantitativas das vilosidades intestinais, interferindo na absorção de nutrientes, como cálcio, fósforo, magnésio, proteínas e lipídios, com consequente redução no peso das aves.

Expression patterns of influenza virus receptors in the respiratory tracts of four species of poultry

The primary determinant of influenza virus infectivity is the type of linkage between sialic acid and oligosaccharides on the host cells. Hemagglutinin of avian influenza viruses preferentially binds to sialic acids linked to galactose by an alpha-2,3 linkage whereas hemagglutinin of human influenza viruses binds to sialic acids with an alpha-2,6 linkage. The distribution patterns of influenza receptors in the avian respiratory tracts are of particular interest because these are important for initial viral attachment, replication, and transmission to other species. In this study, we examined the distribution patterns of influenza receptors in the respiratory tract of chickens, ducks, pheasants, and quails because these species have been known to act as intermediate hosts in interspecies transmission. Lectin histochemistry was performed to detect receptor-bearing cells. Cell-specific distribution of the receptors was determined and expression densities were compared. We observed species-, site-, and cell-specific variations in receptor expression. In general, receptor expression was the highest in quails and lowest in ducks. Pheasants and quails had abundant expression of both types of receptors throughout the respiratory tract. These results indicate that pheasants and quails may play important roles as intermediate hosts for the generation of influenza viruses with pandemic potential.

Genetic trends of absolute and relative heart weight in a male broiler line

Data of chickens from a broiler-breeding program have been collected and used for determination of genetic trends of absolute and relative heart weight. The genetic trends have been estimated by regression of the genetic values of the traits over hatch-year. Genetic values of 42,912 individuals, obtained by restricted maximum likelihood, were used for regression analysis. The estimates of the genetic trends for absolute and relative heart weight were found to be -0.08 g and -0.004% per hatch-year, respectively. These trends show that heart weight in the line analyzed, in absolute and relative terms, has tended to decrease, which can make the metabolic disorders due to the reduction in heart weight in broilers even worse.