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Poultry meat is a valuable source of nutrients and the enrichment with health-promoting substances such as polyunsaturated fatty acids (n-3 PUFA) is an important factor for consumers’ choice. Camelina meal (Camelina sativa) is an animal feedstuff used to achieve this goal, but the administration of n-3 PUFA-enriched diets in broiler nutrition can accelerate the oxidative processes in meat leading to a decreased quality of final product. The aim of this study was to investigate the effect of the organic Cr as chromium picolinate (CrPic) on meat quality, fatty acid profile of fat and oxidative stability of meat from broilers fed supplemented dietary Camelina meal. An experiment was conducted on 240 Ross 308 broiler chicken aged 14 days which were assigned to 6 dietary treatments in a randomized complete block design with a 2 × 3 factorial arrangement. Within the treatment arrangement two concentrations of Camelina meal (0% and 3%) and three concentrations of Cr3+ (0, 200 and 400 μg/kg) were used. Dietary treatments were: (1) Control diet (C) containing a corn–soybean diet with no added Camelina meal or Cr3+; (2) a C diet containing an additional 200 μg/kg of Cr3+ as CrPic; (3) a C diet containing an additional 400 μg/kg of Cr3+ as CrPic; (4) a C diet containing an additional 3% Camelina meal; (5) diet 2 containing an additional 3% Camelina meal; (6) diet 3 containing an additional 3% Camelina meal. Chromium supplementation significantly (P<0.05) increased the CP concentrations and significantly (P<0.05) decreased the crude fat concentrations in breast samples. The Camelina meal groups presented higher values of unsaturated fatty acids, particularly n-3 fatty acids (P<0.05). In CrPic groups, increased retention of Zn and Fe (P < 0.05) was observed in breast samples, compared to control group, and thiobarbituric acid reactive substances values were significantly (P<0.05) smaller. Myoglobin fraction (metmyoglobin and oximyoglobin) concentrations differ significantly (P<0.05) from the control group, under the influence of Cr3+ supplements. This study found that broilers fed with CrPic supplements showed improved mineral composition and oxidative stability of breast meat, proving an effective protection of lipid molecules from oxidation in PUFA-enriched meat.
Chicken primordial germ cells (PGCs) are the primary pluripotent stem cell types that will differentiate towards germ cells. High aldehyde dehydrogenase (ALDH) activity is considered as a functional marker for the detection of cell ‘stemness’. In our study the ALDEFLUOR™ kit was used for determination of ALDH activity in PGCs. PGCs were co-stained with diethylaminobenzaldehyde (DEAB) and ALDH and analyzed by flow cytometry. Our results showed a small cell population (8.0 ± 3.3%) upon preincubation of the cells with the specific inhibitor DEAB, however cells without inhibitor staining showed a fluorescence shift as an ALDH-positive population (70.5 ± 1.6%). These findings indicate higher expression of ALDH in PGCs and ALDH activity can therefore be used as a new functional marker for the detection of cell ‘stemness’ in chicken PGCs. These results may have importance for characterization of PGCs as a potential genetic resource in poultry. Further research is necessary to elucidate the role of this functional marker in these cells.
Many economic losses occur in the poultry industry due to leg fragility. Knowing the genomic regions that influence traits associated with the growth and composition of the leg’s bone can help to improve the selection process leading to increased leg resistance to fracture. The present study aimed to map quantitative trait loci (QTL) for mineral composition and morphometric traits of the tibia in 478 animals from an F2 broiler × layer cross. The measurement of weight, length and width of Tibia was carried out at 42 days of age. Ash, dry matter, levels of calcium (Ca), phosphorus (P), magnesium (Mg), Zinc (Zn) and Calcium:Phosphorus (Ca:P) ratio were also recorded. The population was genotyped for 128 microsatellite markers and one single nucleotide polymorphism, covering 2630 cM of the chicken genome. A likelihood ratio test was performed to find QTLs. Additive and dominance effects of the QTLs were included in the model. In the chromosomes 2 (GGA2), 6 (GGA6), 8 (GGA8), 24 (GGA24) and 26 (GGA26) some suggestive QTLs (P<0.00276) were mapped for tibia weight (GGA2 and GGA26), ash percentage (GGA2 and GGA6), dry matter percentage (GGA2), Ca (GGA8 and GGA24) and Ca:P ratio (GGA8), many of which are close to genes already identified as good candidates for those traits. The suggestive QTL on GGA2 has a pleiotropic effect on ash percentage, dry matter and bone weight, whereas in the GGA8 there seems to be two QTLs, one for Ca and another for Ca:P ratio. Thus, this study identified at least five genomic regions, in different chromosomes, that can be targeted for further research to identify potential mutations influencing the development and composition of leg bones in Gallus gallus.
Furnished cage housing for laying hens has been introduced in some countries as a ‘welfare-friendly’ alternative to conventional cage systems. Whether this housing system would be acceptable to the public remains unknown. This pilot study aimed to engage the public through online discussions in order to investigate their knowledge, support and perception of laying hen welfare housed in furnished cages. During these discussions, a science-based information statement about furnished cages was introduced. Through a mixed method approach, surveys to assess beliefs and knowledge were administered to participants before and after the online discussion. We qualitatively analysed the online discussion transcripts to determine recurrent themes, and quantitatively measured levels of knowledge and support for furnished cages using pre- and post-forum surveys. Support for the introduction increased from 55% pre-forum to 65% post-forum. Additionally, the participants’ perceived welfare of laying hens in furnished cages and objective knowledge of furnished cages significantly increased after online discussion. These results suggest that engagement with the public combined with the delivery of science-based information may be important factors when considering whether to introduce new farming practices. Trust in industry through transparency and willingness to engage in discussions with the public might also mitigate public concerns.
This study aimed to set up methodology to monitor parasite-specific T-cell activation in vitro using Eimeria tenella-infected chickens. A sonicated E. tenella sporozoite protein preparation was used for the activation of chicken spleen cell cultures. Proliferation assessed by 3H-thymidin incorporation or blast transformation of T-cells assessed by immunofluorescence labelling and flow cytometry were used as read-outs for activation. Results showed that E. tenella-specific proliferation was detected in cultures of spleen cells collected in a ‘window’ between 8 and 14 days after primary infection. However, due to high variation in proliferative responses between individuals and to high background proliferation, large numbers of observations were needed to obtain significant results. Moreover, the outcome was not improved by increasing the infection dose to chickens or by depletion of T-cell receptor (TCR) γ/δ expressing cells from cultures. An E. tenella-specific blast transformation response was observed for TCRα/β expressing cells within the same ‘window’, confirming the identity of the responding cells as classic T-cells. Thus, it is possible to study the kinetics of E. tenella-specific T-cell responses in vitro. However, more in-depth phenotypic identification of the responding T-cells could improve the methodology.
The gut has great importance for the commercial success of poultry production. Numerous ion transporters, exchangers, and channels are present on both the apical and the basolateral membrane of intestinal epithelial cells, and their differential expression along the crypt-villus axis within the various intestinal segments ensures efficient intestinal absorption and effective barrier function. Recent studies have shown that intensive production systems, microbial exposure, and nutritional management significantly affect intestinal physiology and intestinal ion transport. Dysregulation of normal intestinal ion transport is manifested as diarrhoea, malabsorption, and intestinal inflammation resulting into poor production efficiency. This review discusses the basic mechanisms involved in avian intestinal ion transport and the impact of development during growth, nutritional and environmental alterations, and intestinal microbial infections on it. The effect of intestinal microbial infections on avian intestinal ion transport depends on factors such as host immunity, pathogen virulence, and the mucosal organisation of the particular intestinal segment.
Feed efficiency traits (FETs) are important economic indicators in poultry production. Because feed intake (FI) is a time-dependent variable, longitudinal models can provide insights into the genetic basis of FET variation over time. It is expected that the application of longitudinal models as part of genome-wide association (GWA) and genomic selection (i.e. genome-wide selection (GS)) studies will lead to an increase in accuracy of selection. Thus, the objectives of this study were to evaluate the accuracy of estimated breeding values (EBVs) based on pedigree as well as high-density single nucleotide polymorphism (SNP) genotypes, and to conduct a GWA study on longitudinal FI and residual feed intake (RFI) in a total of 312 chickens with phenotype and genotype in the F2 population. The GWA and GS studies reported in this paper were conducted using β-spline random regression models for FI and RFI traits in a chicken F2 population, with FI and BW recorded for each bird weekly between 2 and 10 weeks of age. A single SNP regression approach was used on spline coefficients for weekly FI and RFI traits, with results showing that two significant SNPs for FI occur in the synuclein (SNCAIP) gene. Results also show that these regions are significantly associated with the spline coefficients (q2) for 5- and 6-week-old birds, while GWA study results showed no SNP association with RFI in F2 chickens. Estimated breeding value predictions obtained using a pedigree-based best linear unbiased prediction (ABLUP) model were then compared with predictions based on genomic best linear unbiased prediction (GBLUP). The accuracy was measured as correlation between genomic EBV and EBV with the phenotypic value corrected for fixed effects divided by the square root of heritability. The regression of observed on predicted values was used to estimate bias of methods. Results show that prediction accuracies using GBLUP and ABLUP for the FI measured from 2nd to 10th week were between 0.06 and 0.46 and 0.03 and 0.37, respectively. These results demonstrate that genomic methods are able to increase the accuracy of predicted breeding values at later ages on the basis of both traits, and indicate that use of a longitudinal model can improve selection accuracy for the trajectory of traits in F2 chickens when compared with conventional methods.
Heat stress is one of the main challenges in poultry production as it reduces performance in broilers and layers. This review focuses on the impact of heat stress in poultry production with emphasis on broilers and layers, methodologies to measure the severity of stress and dealing the preventive measures to alleviate stress due to heat. Potential use of naked neck and frizzle genes is highlighted. Nutritional interventions including offering a balanced diet, increasing energy, required amino acids, vitamins like vitamins A, E, Se and minerals like Ca, Na, Cl and K additional supplementation of vitamin C, provision of cool water at levels of up to five times of feed intake to satisfy the special needs during heat stress all have proven advantages. Designing housing with gable type roofing and open sided, wet curtains/exhaust fans, tunnel ventilation in environment control houses, provision of more floor space and free movement, to exhibit natural movement and decreasing flock density is useful to minimise stress as well as to regulate the temperature in micro environment. Thermos tolerance in birds can be enhanced by early feed restriction, good management with better ventilation and developing of heat tolerant breeds by selecting for less feathers. Selection of breeds suitable to climate, nutritional manipulation and small management changes can minimise heat stress in birds.
Two highly pathogenic avian influenza (HPAI) outbreaks have affected commercial egg production flocks in the American continent in recent years; a H7N3 outbreak in Mexico in 2012 that caused 70% to 85% mortality and a H5N2 outbreak in the United States in 2015 with over 99% mortality. Blood samples were obtained from survivors of each outbreak and from age and genetics matched non-affected controls. A total of 485 individuals (survivors and controls) were genotyped with a 600 k single nucleotide polymorphism (SNP) array to detect genomic regions that influenced the outcome of highly pathogenic influenza infection in the two outbreaks. A total of 420458 high quality, segregating SNPs were identified across all samples. Genetic differences between survivors and controls were analyzed using a logistic model, mixed models and a Bayesian variable selection approach. Several genomic regions potentially associated with resistance to HPAI were identified, after performing multidimensional scaling and adjustment for multiple testing. Analysis conducted within each outbreak identified different genomic regions for resistance to the two virus strains. The strongest signals for the Iowa H5N2 survivor samples were detected on chromosomes 1, 7, 9 and 15. Positional candidate genes were mainly coding for plasma membrane proteins with receptor activity and were also involved in immune response. Three regions with the strongest signal for the Mexico H7N3 samples were located on chromosomes 1 and 5. Neuronal cell surface, signal transduction and immune response proteins coding genes were located in the close proximity of these regions.
Campylobacteriosis, the most frequent bacterial enteric disease, shows a clear yet unexplained seasonality. The study purpose was to explore the influence of seasonal fluctuation in the contamination of and in the behaviour exposures to two important sources of Campylobacter on the seasonality of campylobacteriosis. Time series analyses were applied to data collected through an integrated surveillance system in Canada in 2005–2010. Data included sporadic, domestically-acquired cases of Campylobacter jejuni infection, contamination of retail chicken meat and of surface water by C. jejuni, and exposure to each source through barbequing and swimming in natural waters. Seasonal patterns were evident for all variables with a peak in summer for human cases and for both exposures, in fall for chicken meat contamination, and in late fall for water contamination. Time series analyses showed that the observed campylobacteriosis summer peak could only be significantly linked to behaviour exposures rather than sources contamination (swimming rather than water contamination and barbequing rather than chicken meat contamination). The results indicate that the observed summer increase in human cases may be more the result of amplification through more frequent risky exposures rather than the result of an increase of the Campylobacter source contamination.
Probiotics are live microorganisms with confirmed beneﬁcial effects on poultry health, growth performance, immune system and gut microbial population. A better perception of the mechanisms underlying the immunomodulatory effects of probiotic bacteria is usually needed to give a superior direction to the development and administration of probiotics. The oral administration of probiotic bacteria influence host cytokine levels and therefore, alters both innate and adaptive host immune responses. Selected probiotics, including some lactobacillus isolates and enterococcal strains, have been considered to prevent salmonella colonisation. Part of the effect of probiotic bacteria may be mediated through changes in the immune system related genes, including cytokine expression. Administration of probiotics in chickens could moderate salmonella mediated changes in genes, including encoding pro-inflammatory cytokines, T helper (Th) 1 cytokines, and Th2 cytokines. This review summarises the findings on the mechanisms of salmonella inhibition by using probiotic bacteria at the molecular level.
The liver is the ‘central laboratory’ of a chicken's body, responsible for sorting and transforming digested compounds as well as dealing with waste products. It is essential that this organ is kept in an excellent condition in order to maintain a healthy bird. Viral hepatitis in poultry is a complex disease syndrome caused by several viruses belonging to different families, including fowl adenoviruses (FAdV), avian hepatitis E virus (HEV), duck hepatitis virus (DHV), and turkey hepatitis virus (THV). Although, these viruses target the liver primarily, they each possess unique clinical and biological features. Hydropericardium syndrome (HPS) is a highly infectious disease caused by FAdV serotype 4 (FAdV-4) affecting poultry, especially broilers, and is characterised by the accumulation of fluid in the pericardial sac and hepatitis. Inclusion body hepatitis (IBH) was recognised firstly in the US, and the disease has now been reported in many countries. FAdV, the causative agent of inclusion body hepatitis, is a Group I avian adenovirus in the genus Aviadenovirus. The affected birds have a pale, swollen, friable, and haemorrhagic liver with pathognomonic histological lesions including intranuclear inclusion bodies in the nuclei of the hepatocytes. Avian HEV naturally infects chickens and is associated with hepatitis-splenomegaly syndrome, although the majority of the infected birds are subclinical. THV is a picornavirus that is likely the causative agent of turkey viral hepatitis. Currently there are more questions than answers about THV, and pathogenesis and clinical impact remains largely unknown. Future research into viral hepatic diseases of poultry is warranted to develop effective vaccines, specific diagnostic assays, and identify suitable cell culture systems for virus propagation. This review covers the common and unique features of major hepatitis causing viruses, with emphasis on FAdV, HEV and THV in an effort to identify the knowledge gaps and aid prevention and control of poultry viral hepatitis.
Avian pathogenic Escherichia coli (APEC) is one of the most
economically damaging diseases affecting the poultry industry. This group of
extra-intestinal E. coli causes a variety of clinical
conditions including air-sacculitis and cellulitis. The economic impact of APEC
is mainly due to mortality, slower growth rates and carcass downgrading. In
commercial broiler operations, APEC infections are controlled indirectly by
vaccination against other respiratory diseases and minimising stress conditions,
and directly by administration of antimicrobial agents to suppress symptoms in
infected flocks. Several studies have demonstrated that the most common
virulence factors studied in APEC are rarely present in the same isolate,
showing that APEC strains constitute a heterogeneous group. Different isolates
may harbour different associations of virulence factors, each able to induce
colibacillosis. Despite its economical relevance, the pathogenesis of
colibacillosis is poorly understood. The O antigen, a component of the surface
lipopolysaccharide, has been identified as a promising vaccine target. With the
availability of a novel bioconjugation technology it is expected that
multivalent O antigen conjugate vaccines can be produced on an industrial scale.
Despite the potential for developing an efficacious vaccine to combat this
economically important poultry disease, several obstacles hinder such efforts.
These include cost, vaccine delivery method and timing of vaccination. The
present discusses current knowledge on APEC virulence, host response to
infection and various attempts to develop an effective vaccine
Human campylobacteriosis is the most commonly reported gastrointestinal bacterial infection in the EU; poultry meat has been identified as the main source of infection. We tested the hypothesis that enhanced biosecurity and other factors such as welfare status, breed, the practice of partial depopulation and number of empty days between flocks may prevent Campylobacter spp. caecal colonization of poultry batches at high levels (>123 000 c.f.u./g in pooled caecal samples). We analysed data from 2314 poultry batches sampled at slaughter in the UK in 2011–2013. We employed random-effects logistic regression to account for clustering of batches within farms and adjust for confounding. We estimated population attributable fractions using adjusted risk ratios. Enhanced biosecurity reduced the odds of colonization at partial depopulation [odds ratio (OR) 0·25, 95% confidence interval (CI) 0·14–0·47] and, to a lesser extent, at final depopulation (OR 0·47, 95% CI 0·25–0·89). An effect of the type of breed was also found. Under our assumptions, approximately 1/3 of highly colonized batches would be avoided if they were all raised under enhanced biosecurity or without partial depopulation. The results of the study indicate that on-farm measures can play an important role in reducing colonization of broiler chickens with Campylobacter spp. and as a result human exposure.
The relationships between metabolic pathways, nutrients and genes are the basis of the majority of current studies on poultry. The rapid advance of biochemical and molecular tools has now made it possible to understand the molecular base of important phenotypic characteristics. Fats are the main storage source of energy in animal body with important role in cell membrane structure, gene regulation and precursors of important regulatory metabolites. From a functional point of view, it has been suggested that dietary fats change liver fatty acid synthesis and other lipogenic enzymes by regulating mRNA synthesis. Nuclear hormone receptors are defined as ligand-activated transcription factors which directly and indirectly regulate a number of genes involved in lipid metabolism and inflammatory signalling. The peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily of transcription factors. PPARs are involved in cellular differentiation, insulin sensitisation, cancer, atherosclerosis and several metabolic diseases. Three distinct PPAR genes have been recognised as α, δ and γ. The most important metabolic effect of PPARγ is its role in adipogenesis. PPARγ is a central gene regulator in adipose tissue and stimulate the expression of several genes involved in adipogenesis. Based upon examples taken from chicken lipid metabolism, it is possible to draw lessons from the study of PPARγ functions in order to approach the study of gene expression PPARγ functions regulatory pathways interactions.
AA amyloidosis (AAA) is a disease known as amyloid arthropathy in chicken, which represents substantial economic losses, in addition to welfare concerns. Enterococcus faecalis (E. faecalis) is the major pathogen found in field outbreaks of amyloid arthropathy and its specific association with this disease has been extensively confirmed. The following review discusses the sequence types of E. faecalis associated with AAA that have been identified and characterised both poultry and humans and provide different hypotheses and theories about pathogenesis and transmission of this disease. This article covers the pathology both in field and induced cases of avian amyloidosis and concludes with approaches for a possible treatment, needs for further research and future perspectives. This paper is a consolidation of current knowledge on AAA in chickens which has been obtained over the last twenty years.
Peroxisome proliferator-activated receptors (PPAR) belong to a family of nuclear hormone receptors that are activated by fatty acids such as polyunsaturated fatty acids (PUFA) and/or their derivatives. Three isoforms of PPAR namely α (alpha), β (beta), and γ (gamma) are found to be highly expressed in tissues relevant to energy homeostasis. The PPAR signalling pathway, which is involved in lipid metabolism and storage, play a role in livestock meat quality. Elucidating the molecular mechanisms of PPAR action of fat metabolism may have extensive implications not only in animal biology for health and feed efficiency improvement, but also in molecular nutrition as a potent nutritional supplement in poultry species.
The aim of the present study was to examine whether high intake of lean or fatty fish (cod and farmed salmon, respectively) by healthy, normal-weight adults would affect risk factors of type 2 diabetes and CVD when compared with lean meat (chicken). More knowledge is needed concerning the potential health effects of high fish intake (>300 g/week) in normal-weight adults. In this randomised clinical trial, thirty-eight young, healthy, normal-weight participants consumed 750 g/week of lean or fatty fish or lean meat (as control) for 4 weeks at dinner according to provided recipes to ensure similar ways of preparations and choices of side dishes between the groups. Energy and macronutrient intakes at baseline and end point were similar in all groups, and there were no changes in energy and macronutrient intakes within any of the groups during the course of the study. High intake of fatty fish, but not lean fish, significantly reduced TAG and increased HDL-cholesterol concentrations in fasting serum when compared with lean meat intake. When compared with lean fish intake, fatty fish intake increased serum HDL-cholesterol. No differences were observed between lean fish, fatty fish and lean meat groups regarding fasting and postprandial glucose regulation. These findings suggest that high intake of fatty fish, but not of lean fish, could beneficially affect serum concentrations of TAG and HDL-cholesterol, which are CVD risk factors, in healthy, normal-weight adults, when compared with high intake of lean meat.
Fertile eggs from Cobb 500 broiler breeder hens were incubated to provide low starting egg shell temperatures (EST; 36.9°C to 37.3°C) which were gradually increased to 37.8°C during the first 7 to 15 days of incubation compared with eggs incubated with a constant EST of 37.8°C (standard conditions) over the first 18 days of incubation. Time of individual chick hatching (measured at 6 h intervals from 468 h of incubation), chick weight, chick length and yolk weight were measured at take-off and BW was measured at 7, 14, 28, 34 and 42 days of age. Male birds at 34 and 42 days of age were assessed for their ability to remain standing in a latency-to-lie test. At 34 and 42 days, male birds were examined for leg symmetry, foot pad dermatitis, hock bruising and scored (scale 0 to 4, where 0=no lesion and 4=lesions extending completely across the tibial growth plate) for tibial dyschondroplasia (TD) lesions. The lower EST profiles caused chicks to hatch later than those incubated under the standard EST profile. Chicks which hatched at ⩽498 h incubation grew faster over the first 7 days than those that hatched later. There were significantly more birds (only males were studied) that hatched from the lower EST profiles with TD scores of 0 and 1 and fewer with score 4 at 34 days than those hatched under the standard profile. Male birds at 34 days with TD lesions ⩾3 stood for significantly shorter times than males with TD scores ⩽2. Moreover, male birds at 34 and 42 days with TD lesion scores of ⩾3 hatched significantly earlier and grew significantly faster over the first 2 weeks of age than did male birds with TD scores ⩽2. It appears possible to decrease the severity and prevalence of TD in the Cobb 500 broiler by ensuring that the birds do not hatch before 498 h of incubation.
In the early 21st century, genetic modification of chicken primordial germ cells (PGCs) had not been possible before their transfer and recovery through germ line. Chicken PGCs resist deliberate genetic modification, probably by silencing the transgenes in the genome. The use of mobile genetic elements (transposons) in genetic modification and germ-line transmission of PGCs has recently overcome this problem, so that PGCs can be used for further chicken genome modelling in order to study developmental biology, non-coding RNA (ncRNA) functions, viral DNA-RNA hybridisation, silencing of transgene expression, together with epigenetic modification, and gene function. Application of the transposons, viral integrase, zinc-finger nuclease and site-specific recombinase in whole genome elucidation is not sufficient. The chicken PGCs can be used as a model of choice to establish a new generation of methodology for genome modelling. For this purpose the livesome vectors are proposed.