Effect of moderate and severe heat stress on avian embryonic Hsp70 gene expression

Stress response is a universal mechanism developed by all organisms to deal with adverse changes in the environment, which lead to the synthesis of heat shock proteins (Hsps). In this study, the effect of moderate (41degreesC) and severe (44degreesC) heat stress on Hsp70 transcript expression pattern was investigated during chicken embryogenesis. Acute exposure to severe heat stress for one hour resulted in a fifteen-fold increase in Hsp70 mRNA levels. The return of stressed embryos to normal incubation temperature resulted in Hsp70 mRNA levels five-fold higher than control after three hours and normal levels after six hours. Moderate heat stress did not induce enhancements on Hsp70 mRNA levels. The spatial expression of Hsp70 transcripts was detected in embryos under normal incubation conditions. Whole-mount in situ hybridization analysis showed that Hsp70 transcripts were constitutively present in somite and in distinct encephalic domains (predominantly in prosencephalon and mesencephalon areas) of the chicken embryo. These results showed that Hsp70 induction is dependent on incubation temperature conditions, suggesting that early chicken embryos may induce a quick emergence response to cope with severe heat stress by increasing Hsp70 mRNA levels.

Serosurvey of selected avian pathogens in brazilian commercial Rheas (Rhea americana) and Ostriches (Struthio camelus)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Disseminated avian tuberculosis in captive Ara macao

Avian mycobacteriosis was diagnosed in a captive scarlet macaw (Ara macao) that presented multifocal granulomas on subcutaneous tissue, sciatic nerves, infraorbital sinus, trachea, air sacs, muscles, spleen and liver. Microscopically, central areas of caseous necrosis surrounded by epithelioid macrophage, multinucleated giant cells, and lymphocytes were observed. Acid-fast bacilli were demonstrated by Ziehl-Neelsen stain. Inoculation into Lowenstein-Jensen, Stonebrink and Petragnani media, yielded Mycobacterium spp, which was identified as Mycobacterium avium by polymerase chain reaction technique (PCR).

Thyroid status, but not insulin status, affects expression of avian uncoupling protein mRNA in chicken

The aim of this study was to investigate the hormonal regulation of the avian homolog of mammalian uncoupling protein (avUCP) by studying the impact of thyroid hormones and insulin on avUCP mRNA expression in chickens (Gallus gallus). For 3 wk, chicks received either a standard diet (control group), or a standard diet supplemented with triiodothyronine (T-3; T3 group) or with the thyroid gland inhibitor methimazole (MMI group). A fourth group received injections of the deiodinase inhibitor iopanoic acid (IOP group). During the 4th wk of age, all animals received two daily injections of either human insulin or saline solution. The results indicate a twofold overexpression of avUCP mRNA in gastrocnemius muscle of T3 birds and a clear downregulation (-74%) in MMI chickens compared with control chickens. Insulin injections had no significant effect on avUCP mRNA expression in chickens. This study describes for the first time induction of avUCP mRNA expression by the thermogenic hormone T3 in chickens and supports a possible involvement of avUCP in avian thermogenesis.

Cold-induced enhancement of avian uncoupling protein expression, heat production, and triiodothyronine concentrations in broiler chicks

The relationships among avian uncoupling protein (avUCP) mRNA expression, heat production, and thyroid hormone metabolism were investigated in 7-14-day-old broiler chicks (Gallus gallus) exposed to a low temperature (cold-exposed chicks, CE) or a thermoneutral temperature (TN). After 7 days of exposure, CE chicks exhibited higher heat production (+83%, P < 0.01), avUCP mRNA expression (+20%, P < 0.01), and circulating triiodothyronine (T-3) levels (+104%, P = 0.07) for non-statistically different body weights and feed intake between 3 and 7 days of exposure as compared to TN chicks. Plasma thyroxine (T-4) concentration was clearly decreased in CE chicks (-33%, P = 0.06). The lower hepatic inner-ring deiodination activity (-47%) and the higher renal outer-ring deiodination activity (+75%) measured in CE compared to TN chicks could partly account for their higher plasma T3 concentrations. This study describes for the first time the induction of avUCP mRNA expression by low temperature in chickens, as it has been previously shown in ducklings, and supports the possible involvement of avUCP in avian thermogenesis. (C) 2003 Elsevier B.V. (USA). All rights reserved.

Detection and transfer of antimicrobial resistance gene integron in Salmonella Enteritidis derived from avian material

The expansion of global poultry production has increased the need to reduce or control the agents responsible for economic losses, including Salmonella spp. These bacteria are also of public health concern due to their potential to cause food poisoning, and, more recently, due to the antimicrobial resistance presented by these bacteria. Molecular biology is an important tool currently used in the diagnosis and research studies of main poultry diseases. The present studied analyzed 100 samples of Salmonella Enteritidis (SE) isolated from avian material aiming at detecting the class 1 integron gene, Integroninvolved in antimicrobial resistance, by means of polymerase chain reaction (PCR), and comparing it with plate inhibition test. Subsequently, SE samples were evaluated for their capacity to horizontally transfer this gene. There was no direct relationship between the presence of the class 1 integron gene and SE resistance to the 14 antimicrobials tested, as 80% of the studied samples were resistant to up to three antimicrobials, and did not present the aforementioned gene. However, horizontal transfer of this gene was accomplished in vitro (from Escherichia coli to Salmonella Enteritidis), demonstrating that capacity class 1 integron gene can be disseminated among enterobacteria.

Using post-release monitoring data to optimize avian reintroduction programs: a 2-year case study from the Brazilian Atlantic Rainforest

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Molecular epidemiology and evolution of avian infectious bronchitis virus

Mutation and recombination processes are involved in the genetic and phenotypic variations of RNA viruses, leading to the emergence of new variant strains, and give rise to virus population diversity to be modeled by the host, particularly by the immune system, as occurred with infectious bronchitis virus (IBV) in chickens. The consequence is a continuous emergence of new IBV variants with regard to pathotypes, serotypes, and protectotypes. Nucleotide sequencing and subsequent genetic analysis of the S1 and N protein gene sequences provide a fast and accurate method to classify and predict IBV genotype, and a powerful instrument to monitor phylogenetic and epidemiological evolution of IBV variants. Despite the use of vaccination programmes, infectious bronchitis has become a serious problem in Brazil. Thus, a significant number of IBV field variants have been identified circulating in the Brazilian commercial poultries between 2000 to 2006 and more recently in Argentina. These viruses seem to be indigenous, because they demonstrated a low genetic relatedness with the majority of the reference strains from North America, Europe and Asia, but were moderately to highly related one to another. In summary, indigenous field IBV variants were evolving and circulating in the field in Brazil and Argentina, and should be considered as initial candidates for protection against current IBV infectious in chickens. However, in vitro and in vivo studies are needed to determine the pathogenicity and immunogenecity of these new isolates, before defining a new vaccine strain.

Genetic grouping of avian infectious bronchitis virus isolated in Brazil based on RT-PCR/RFLP analysis of the S1 gene

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mast cells in the developing avian eye

Mast cells are present in the eye of Gallus domesticus, appearing in the anterior uvea in embryos at stage 39 HH (13th day). In hatching and adult birds, they are present in the sclera, uvea, pectinate Ligament, and conjunctiva. Mast cells are absent in the cornea, retina, and pecten oculi.Maturing mast cells in the anterior eye segment appear as round cells having eccentric nuclei and a few cytoplasmic metachromatic granules, whose fluorescence increases during development. Mature cells are more numerous in late development, and their cytoplasm is rich in metachromatic and intensely fluorescent granules. Ultrastructurally, maturing mast cells display progranules and a few electron dense and homogeneous granules on one side of the cell. Mast cells of adult birds possess homogeneous cytoplasmic granules, some of which display protuberances that penetrate hollows of adjoining granules. Heterogeneous granules exhibiting latticed and mottled patterns are also present. The existence of mast cells in the anterior eye segment indicates that these cells might perform a physiological role during development and in aqueous humor outflow. They might modulate exchanges between blood and aqueous humor through chemical mediators present in their granules. (C) 1996 Wiley-Liss, Inc.

Gap junctions between mast cells and fibroblasts in the developing avian eye

Mast cells are present in the eye of chick embryos from the 14th day onward, displaying metachromatic granules, mainly in the iris anterior surface and pectinate ligament. Ultrastructurally these cells show electron-dense granules and a few thin and short cytoplasmic projections in close contact with fibroblasts. Sometimes these contacts are extensive, with long fibroblast projections partially involving the mast cells. Gap junctions between mast cells and fibroblasts are observed only in the eyes of 16- and 20-day-old embryos. These intercellular specializations are represented by a close apposition of cytoplasmic membranes with an extension up to 300 nm. Gap junctions between mast cells and fibroblasts were not observed previously in vivo or in vitro, although in vitro studies have shown that a number of functionally critical interactions may occur between these cells. Our morphological findings suggest that, in vivo, fibroblasts interact with mast cells and may influence their maturation.

Avaliação do perfil eletroforético das proteínas séricas em matrizes pesadas (gallus gallus domesticus) da linhagem avian farm

This work is aimed to determine the profile of electrophoretic serum protein in healthy adult broiler breeders (Gallus gallus domesticus) of the Avian farm strain. Fifteen breeders aging 63 weeks from Conchas, city located in the State of São Paulo, were assessed. The biuret method was used to obtain the total serum protein values and protein fractions separation through electrophoresis technique in agarose gel, and film reading through densitometry in 520nM. Seven fractions were obtained, whereas, β 1 - globulin and β 2 - globulin were not cited by the authors in the textbooks checked. The prealbumin fraction was identified only in six out of 15 samples analyzed. In five breeders, it was observed the division of g - globulin into two fractions named g - 1 and g - 2, according to the electrophoretic mobilities. The relation albumin/globulin (A/G) found in the experiment agrees with the other authors cited, demonstrating that it decreases as the age increases.

Structural, cytochemical, immunocytochemical and ultrastructural characterization of blood granulocytes of the roadside hawk Buteo magnirostris (Gmelin, 1788) (Avian, Falconiform)

In the peripheral blood of the roadside hawk, Buteo magnirostris, the following types of granulocytic leucocytes were identified: heterophil, eosinophil and basophil. The heterophils presented acidophilic and spindle shaped granules, the eosinophils possess spherical eosinophilic granules and the basophils showed spherical and basophilic granules. The heterophils and eosinophils presented positive cytochemical reaction to glycogen and basic polyaminoacid, while the eosinophils presented sudanophilic granules, which were also positive for myeloperoxidase. The heterophils, alone, presented positivity for acid phosphatase in some granules and immunoreactivity to TGF-β1 was observed only in the cytoplasm of the eosinophils. Electron microscopy demonstrated the heterophil granules as predominantly spindle shaped, being strongly electron-dense, while the eosinophils had numerous uniformly electron-dense spherical granules and the basophils presented three different types of granules identified according to their electron-density and the aspect of their matrix.