1. Quantitative real-time PCR was carried out to evaluate gene expression of heat shock proteins (HSP) (HSP27, HSP56, HSP60, HSP70, HSP90 and ubiquitin) in the brain (hindbrain, midbrain, forebrain) of chickens with cold-induced pulmonary hypertension.

2. The ratio of the right ventricle to the total ventricle (index of pulmonary hypertension in chickens) was increased in the cold-induced pulmonary hypertensive chickens at 42 d of age compared with control. The HSP genes were expressed in the three parts of the brain in the two experimental groups.

3. In the hindbrain of cold-induced pulmonary hypertensive chickens, the relative gene expression of HSP27, HSP60, HSP70 and HSP90 was decreased while gene expression of HSP56 and ubiquitin was increased compared with controls.

4. In the midbrain of cold induced-pulmonary hypertensive chickens, the expression of HSP56, HSP60, HSP70 and ubiquitin genes was increased compared with controls while HSP27 and HSP90 were decreased.

5. In the forebrain of cold induced-pulmonary hypertensive chickens, the expression of HSP56, HSP60, HSP70 and ubiquitin genes was increased while the expression of the HSP27 gene was decreased compared with controls.

6. It is concluded that overexpression of HSPs in the forebrain and midbrain probably delays the pathological process of cold stress whereas diminished expression of HSP genes in the hindbrain may affect the normal function of brain centres in this area to exacerbate pulmonary hypertension.

2. The induction and consumption of the HS factor heat shock factor (HSF)-1, and reductions of HSF-2 and HSF-3 induced by HS led to a delay in Hsp90 expression. HSF-1, 2 and 3 regulation of hsp90 expression in turn inhibited the synthesis and activation of protein kinase β (Akt), which resulted in a significant increase in caspase-3 at 2 and 10 h, caspase-9 from 1 to 7 h (except at 5 h), and the heat-stressed apoptosis of the myocardial cells.

3. Administration of aspirin changed the expression patterns of HSF-1, 2 and 3 such that the expression of Hsp90 protein was significantly upregulated (by 2.3–4.1 times compared with that of the non-treated cells). The resultant increase in Akt expression and activation, compared with the HS group, inhibited caspase-3 and caspase-9 activities and reduced the myocardial cells apoptosis rate (by 2.14–2.56 times).

4. Aspirin administration could inhibit heat-stressed apoptosis of myocardial cells in vivo and may be closely associated with its promotion of HS response of chicken hearts, especially Hsp90 expression.  相似文献   

1. The growth of the avian embryo is paralleled by an exponential increase in the rate of whole-embryonic oxygen consumption, which potentially increases oxidative damage.

2. Age-related patterns of tissue lipid peroxidation were characterised in brain, liver and heart tissue of developing Japanese quail (Coturnix japonica) embryos between 9 and 15 d of age, over which embryo mass increased by a factor of 6. Lipid peroxidation was quantified in each tissue by spectrophotometric measurement of malondialdehyde using the thiobarbituric acid reactive substances assay.

3. In all tissues, lipid peroxidation increased greatly as development proceeded. Concentrations of malondialdehyde increased in parallel with the cumulative amount of oxygen consumed by the developing embryo consistent with the hypothesis that oxidative stress results from the production of free radicals due to oxidative metabolism.

4. This study describes in vivo oxidative stress in developing avian embryos and suggests that rates of embryonic growth, oxidative metabolism and oxidative damage likely vary in parallel.

1. An experiment was conducted to test the hypothesis that muscle damage in fast-growing broiler chickens is associated with an ambient temperature that does not permit the birds to lose metabolic heat resulting in physiological heat stress and a reduction in meat quality.

2. The experiment was performed in 4 climate chambers and was repeated in 2 trials using a total of 200 male broiler chickens. Two treatments compared the recommended temperature profile and a cool regimen. The cool regimen was defined by a theoretical model that determined the environmental temperature that would enable heat generated by the bird to be lost to the environment.

3. There were no differences in growth rate or feed intake between the two treatments. Breast muscles from birds on the recommended temperature regimen were lighter, less red and more yellow than those from the cool temperature regimen. There were no differences in moisture loss or shear strength but stiffness was greater in breast muscle from birds housed in the cool compared to the recommended regimen.

4. Histopathological changes in the breast muscle were similar in both treatments and were characterised by mild to severe myofibre degeneration and necrosis with regeneration, fibrosis and adipocyte infiltration. There was no difference in plasma creatine kinase activity, a measure of muscle cell damage, between the two treatments consistent with the absence of differences in muscle pathology.

5. It was concluded that breast muscle damage in fast-growing broiler chickens was not the result of an inability to lose metabolic heat at recommended ambient temperatures. The results suggest that muscle cell damage and breast meat quality concerns in modern broiler chickens are related to genetic selection for muscle yields and that genetic selection to address breast muscle integrity in a balanced breeding programme is imperative.

1. Two experiments were conducted to test the hypothesis that when using similar protein/amino acid diets and environment temperature conditions, the performance and carbon turnover in muscle and liver tissues, as measured by the incorporation of stable isotopes (¹³C/¹²C), must be different between fast-growing Cobb 500® and slow-growing Label Rouge broilers.

2. For both experiments (Cobb and Label Rouge), 21-d-old birds were distributed in a completely randomised, 3 × 3 factorial design; three environmental temperatures (cyclic heat stress ad libitum, 22°C ad libitum, and 22°C restricted) and three crude protein concentrations (189.1, 210 and 220 g/kg CP) were used.

3. The Cobb 500® had better performance with higher concentrations of crude protein. Cyclic heat stress (a temperature factor), negatively affected this genetic strain’s performance. For the Label Rouge birds, the crude protein concentrations in the diet presented inconsistent results and cyclic heat stress did not affect the performance.

4. The carbon turnover rate was affected in the Cobb 500® strain, with a high protein content reducing carbon turnover in the evaluated tissues (liver and muscles). Feed intake had a greater impact on carbon turnover rates than cyclic heat stress. The Label Rouge birds were not affected by the evaluated factors, suggesting that genetic improvement has a leading role on tissue carbon turnover.

5. There is a genetic influence on carbon turnover in the liver and muscle tissues of broiler chickens. In addition, genetically fast-growing broilers are more susceptible to variations in diet composition and environmental temperature than less rapidly growing animals.

1. Skeletal abnormalities, bone deformities and fractures cause significant losses in broiler production during both rearing and processing. Silicon is an essential mineral for bone and connective tissue synthesis and for calcium absorption during the early stages of bone formation.

2. Performance was not affected by the addition of silicon. However, broilers receiving silicon showed a significant increase of phosphorus, zinc, copper, manganese and ash in the tibia.

3. In conclusion, broiler performance was not impaired by adding the tested silicon product to the drinking water. In addition, bone development improved, as demonstrated by higher mineral and ash content.

4. Further studies are required to determine the optimal concentration of silicon, including heat stress simulations, to better understand the effects of silicon on bone development.

1. The aim of this study was to construct lentivirus-mediated short hairpin RNA (shRNA) vectors targeting the duck MSTN gene and investigate whether these vectors can affect the development of duck primary cultured embryonic myoblasts.

2. MSTN mRNA levels in the myoblasts were detected using quantitative real-time polymerase chain reaction (PCR), cell proliferation was assessed by MTT assays and cell differentiation was assayed by photography.

3. MSTN mRNA levels in PLL3.7-MSTN-shRNA1, PLL3.7-MSTN-shRNA2 and PLL3.7-MSTN-shRNA3 lentivirus-mediated shRNA groups were reduced by 61.6%, 76.9% and 79.1%, respectively, compared to control cells.

4. Down-regulation of MSTN in duck embryonic myoblasts stimulated cell proliferation and inhibited differentiation, accompanied by a greater than twofold down-regulation of MyoD expression and up-regulation of Myf5 expression.

5. These results revealed that silencing of MSTN changes the development of duck embryonic myoblasts by regulating the expression level of MyoD and Myf5 genes.

1. The aim of this study was to identify the most relevant welfare indicators for unloading, lairage, stunning, killing and post-mortem inspection in a poultry slaughter plant. Different indicators were unloading duration, lairage time, environmental variables in the lairage facilities, shackling time and electrical variables used in the water bath.

2. Lairage time did not correlate strongly with dead on arrival. Heat stress was limited by means of ventilation systems, correct cage placement and appropriate stocking density per crate. The acceptable shackling period was about 30 s.

3. The presence of a corneal reflex showed that an animal was alive, while spontaneous wing flapping, spontaneous eye blinking and response to a painful stimulus were regarded as indicators of stunning efficiency.

4. It was concluded that the presence of recent traumatic injuries during the post-mortem inspection could be a valid means to establish whether corrective measures concerning the handling, transport and loading procedures should be taken.

1. Pediococcus spp. were isolated from poultry rectum, faeces and food as good probiotic candidates in order to select strains to be used as probiotic in poultry feed.

2. A total of 168 lactic acid bacteria were isolated and 51 isolates including 31 Lactobacillus spp. and 20 Pediococcus spp. were able to survive in low pH and bile salt concentration. The Pediococcus spp. were identified and their ability to form biofilm, adhesion to Caco-2 cells and antimicrobial activities against enteric pathogenic bacteria were determined.

3. The results showed the presence of two strains, Pediococcus acidilactici P17 and P19 in rectal swab samples from 21-d old chickens with significant antibacterial activities against Salmonella enteritidis and Escherichia coli.

4. The results suggest that only a few isolates of Pediococcus with potential probiotic activities are present in the poultry industry.

1. The present study was conducted to compare the susceptibility of congenic Fayoumi lines to Eimeria tenella infection and to assess genetic differences in Eimeria egression.

2. Chickens were orally inoculated with 5 × 10⁴ sporulated E. tenella oocysts and challenged with 5 × 10⁶ oocysts on the 10th day after the primary infection.

3. The Fayoumi M5.1 line exhibited higher levels of body weight gain, less oocyst shedding and higher percentages of B and CD4⁺/CD8⁺ T cells than the M15.2 chickens.

4. These results demonstrate that M5.1 line is more resistant to E. tenella infection than M15.2 line. Furthermore, the percentage of sporozoite egress from peripheral blood mononuclear cells (PBMCs) was higher in the M5.1 line.

5. The results of this study suggest that enhanced resistance of Fayoumi M5.1 to E. tenella infection may involve heightened cell-mediated and adaptive immunity, resulting in reduced intracellular development of Eimeria parasites.

1. Measuring the ratio of heterophils and lymphocytes (H/L) in response to different stressors is a standard tool for assessing long-term stress in laying hens but detailed information on the reliability of measurements, measurement techniques and methods, and absolute cell counts is often lacking.

2. Laying hens offered different sites of the nest boxes at different ages were compared in a two-treatment crossover experiment to provide detailed information on the procedure for measuring and the difficulties in the interpretation of H/L ratios in commercial conditions.

3. H/L ratios were pen-specific and depended on the age and aviary system. There was no effect for the position of the nest. Heterophiles and lymphocytes were not correlated within individuals. Absolute cell counts differed in the number of heterophiles and lymphocytes and H/L ratios, whereas absolute leucocyte counts between individuals were similar. The reliability of the method using relative cell counts was good, yielding a correlation coefficient between double counts of r > 0.9.

4. It was concluded that population-based reference values may not be sensitive enough to detect individual stress reactions and that the H/L ratio as an indicator of stress under commercial conditions may not be useful because of confounding factors and that other, non-invasive, measurements should be adopted.

1. the force required to produce tensile failure did not vary linearly with the width of the piece of shell under test, but with its two‐thirds power;

2. it varied linearly with the thickness of the shell;

3. the line relating force at tensile failure to shell thickness did not pass through the origin but intercepted the thickness axis at between about 90 and 130 μm, indicating that the inner layers of a shell, up to about a third of its thickness, contributed little or nothing to its tensile strength;

4. the slope of the line did not vary with hen or strain of hen, indicating that the shells did not differ in the tensile strength of the material constituting their outer layers (i.e. about the outer two‐thirds);

5. there were differences between hens and strains in the magnitude of the intercept: shells of the same thickness but from different hens or strains differed in force at tensile failure;

6. the existence of between‐strain differences in intercept constitutes prima facie evidence that the variation in this trait is under genetic control;

7. there was a fairly large within‐egg residual component of the variance of force at tensile failure; it represents real variation in tensile strength between apparently similar pieces of the same shell and is believed to be an effect of chance in the distribution of flaws in the shell material;

8. for any one hen the intercept is the same as that found when shearing strength is measured, so shearing strength (which can be determined easily, quickly and precisely) can be used as a predictor of tensile strength.

Implications for poultry breeders are discussed; it is suggested that they should select for shell strength instead of shell thickness, measuring strength as shearing strength.  相似文献   

1. A DiagNose II electronic nose (e-nose) system was tested to evaluate the performance of such systems in the detection of the Salmonella enterica pathogen in poultry manure.

2. To build a database, poultry manure samples were collected from 7 broiler houses, samples were homogenised, and subdivided into 4 portions. One portion was left as is; the other three portions were artificially infected with S. enterica.

3. An artificial neural network (ANN) model was developed and validated using the developed database.

4. In order to test the performance of DiagNose II and the ANN model, 16 manure samples were collected from 6 different broiler houses and tested using these two systems.

5. The results showed that DiagNose II was able to classify manure samples correctly as infected or non-infected based on the ANN model developed with a 94% level of accuracy.

1. The post-mortem proteolysis and tenderisation between male and female duck breast muscles were compared.

2. The results showed that μ-calpain activity, desmin content and shear force decreased more quickly in female than in male samples stored at 5°C.

3. It is suggested that the post-mortem proteolysis and tenderisation are more rapid and extensive in female duck breast muscle.

1. The potential use of CpG oligodeoxynucleotides and/or Astragalus polysaccharide (APS) as adjuvants for the culture of chicken bone-marrow-derived dendritic cells (chBM-DCs) was investigated.

2. Chicken dendritic cells (DCs) were isolated and cultured in the presence of recombinant chicken granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4. The chBM-DC displayed typical DC morphology and expressed DC surface markers (MHC-II and CD11c).

3. Cultured chBM-DC showed effective T-cell activation in vitro, based on a mixed lymphocyte response (MLR). Flow cytometry analysis showed an increased proportion of cells expressing CD40 and CD80 in the APS-stimulated culture, compared to the control culture. In the MLR, the APS- and CpG-stimulated chBM-DC could activate T-cells more than control chBM-DC. Real-time PCR assays showed that CpG can activate the TLR21 and an inflammatory response, while APS just reduced the expression of IRF-3.

4. The results demonstrated that in vitro the adjuvant CpG can stimulate chBM-DC to mature by activation of the TLR-signalling pathway, whereas the adjuvant APS stimulates maturation of chBM-DC in vitro to a lesser degree and by another mechanism.

1. The types and methods of use of antibiotics in poultry farms in Cameroon, residual levels and potential microbial resistance were determined.

2. A questionnaire-based survey identified the different antibiotics used and high-performance liquid chromatography (HPLC) was used to determine residual levels of antibiotics.

3. Pathogens were isolated, identified by use of commercial API kits and minimum inhibition concentration (MIC) was determined.

4. Oxytetracyclin, tylocip and TCN (oxytetracycline, chloramphenicol and neomycin) were the most frequently used antibiotics. Antibiotics screened by HPLC were chloramphenicol, tetracycline and vancomycin. All of them except vancomycin were detected, and the concentration of these antibiotics was higher than the maximum residual limits (MRL) set by regulatory authorities.

5. No residues of various antibiotics were found in egg albumen or yolk. The concentration of tetracycline was significantly higher in liver (150 ± 30 µg/g) than in other tissues.

6. Foodborne pathogens, including Salmonella spp., Staphylococcus spp., Listeria spp., Clostridium spp. and Escherichia spp., were identified. Most of the pathogens were resistant to these various antibiotics tested.

7. These findings imply the need for better management of antibiotic use to control sources of food contamination and reduce health risks associated with the presence of residues and the development of resistant pathogens by further legislation and enforcement of regulations on food hygiene and use of antibiotics.

1. The objective of this study was to identify any issues arising during the laboratory testing of samples collected under the National Control Programme for Salmonella.

2. A questionnaire-based survey was conducted among Defra (Department for Environment, Food and Rural Affairs)-approved testing laboratories in order to identify any complicating factors that the laboratories may encounter during the processing of samples.

3. Samples were reported to arrive in good condition and within the specified time frame after collection. The only concern was that new clients may be unaware of the procedure or correct sampling consumables to use.

4. There was evidence of variability between laboratories regarding the sample testing procedure used, with deviation from the guidelines in some cases.

5. This finding suggests that further guidance for laboratories on methodology is likely to be beneficial as this could help improve the detection of low levels of Salmonella.