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In 1977 the pectoralis major (breast) muscle mitochondrial content of domestic broiler chickens, Gallus gallus domesticus, was estimated at 4.1%. However, in the subsequent ∼45 years broilers have been further modified by sustained intensive genetic selection on feed conversion efficiency and breast muscle mass. With a view to understanding the metabolic implications of this historic selection – and also laying a foundation to better interpret current commercial performance – we quantitated the cellular bioenergetic structure of modern broilers. The breast muscle of 4 64 d old Ross308 broilers was subject to morphometric analysis based on transverse Transmission Electron Microscopy (TEM) images. This approach determined an average mitochondrial content, diameter and circularity ratio of 2.1%, 0.42 µm and 0.72, respectively. Broiler breast mitochondrial content has thus approximately halved in the last 45 years and represents one of the lowest contents recorded for the muscle of any eukaryotic species. [ABSTRACT FROM AUTHOR]

Renal blood flow was monitoredin chickens after acute alteration of the renal blood flow to determine the kidney response to changes in perfusion pressure. Regional perfusion in avian kidneys was found to be positively correlated with total perfusion. Further, renal parameters sucg as glomerular filtration rate, urine flow rate and fractional sodium excretion was not significantly modified even with large acute changes in perfusion pressure.

Abstract Background Infectious laryngotracheitis virus (ILTV; gallid herpesvirus 1) infection causes high mortality and huge economic losses in the poultry industry. To protect chickens against ILTV infection, chicken-embryo origin (CEO) and tissue-culture origin (TCO) vaccines have been used. However, the transmission of vaccine ILTV from vaccinated- to unvaccinated chickens can cause severe respiratory disease. Previously, host cell responses against virulent ILTV infections were determined by microarray analysis. In this study, a microarray analysis was performed to understand host-vaccine ILTV interactions at the host gene transcription level. Results The 44 K chicken oligo microarrays were used, and the results were compared to those found in virulent ILTV infection. Total RNAs extracted from vaccine ILTV infected chicken embryo lung cells at 1, 2, 3 and 4 days post infection (dpi), compared to 0 dpi, were subjected to microarray assay using the two color hybridization method. Data analysis using JMP Genomics 5.0 and the Ingenuity Pathway Analysis (IPA) program showed that 213 differentially expressed genes could be grouped into a number of functional categories including tissue development, cellular growth and proliferation, cellular movement, and inflammatory responses. Moreover, 10 possible gene networks were created by the IPA program to show intermolecular connections. Interestingly, of 213 differentially expressed genes, BMP2, C8orf79, F10, and NPY were expressed distinctly in vaccine ILTV infection when compared to virulent ILTV infection. Conclusions Comprehensive knowledge of gene expression and biological functionalities of host factors during vaccine ILTV infection can provide insight into host cellular defense mechanisms compared to those of virulent ILTV.

Abstract Background When compared to primary chicken embryo fibroblast (CEF) cells, the immortal DF-1 CEF line exhibits enhanced growth rates and susceptibility to oxidative stress. Although genes responsible for cell cycle regulation and antioxidant functions have been identified, the genome-wide transcription profile of immortal DF-1 CEF cells has not been previously reported. Global gene expression in primary CEF and DF-1 cells was performed using a 4X44K chicken oligo microarray. Results A total of 3876 differentially expressed genes were identified with a 2 fold level cutoff that included 1706 up-regulated and 2170 down-regulated genes in DF-1 cells. Network and functional analyses using Ingenuity Pathways Analysis (IPA, Ingenuity® Systems, http://www.ingenuity.com) revealed that 902 of 3876 differentially expressed genes were classified into a number of functional groups including cellular growth and proliferation, cell cycle, cellular movement, cancer, genetic disorders, and cell death. Also, the top 5 gene networks with intermolecular connections were identified. Bioinformatic analyses suggested that DF-1 cells were characterized by enhanced molecular mechanisms for cell cycle progression and proliferation, suppressing cell death pathways, altered cellular morphogenesis, and accelerated capacity for molecule transport. Key molecules for these functions include E2F1, BRCA1, SRC, CASP3, and the peroxidases. Conclusions The global gene expression profiles provide insight into the cellular mechanisms that regulate the unique characteristics observed in immortal DF-1 CEF cells.

Abstract Background Infection by infectious laryngotracheitis virus (ILTV; gallid herpesvirus 1) causes acute respiratory diseases in chickens often with high mortality. To better understand host-ILTV interactions at the host transcriptional level, a microarray analysis was performed using 4 × 44 K Agilent chicken custom oligo microarrays. Results Microarrays were hybridized using the two color hybridization method with total RNA extracted from ILTV infected chicken embryo lung cells at 0, 1, 3, 5, and 7 days post infection (dpi). Results showed that 789 genes were differentially expressed in response to ILTV infection that include genes involved in the immune system (cytokines, chemokines, MHC, and NF-κB), cell cycle regulation (cyclin B2, CDK1, and CKI3), matrix metalloproteinases (MMPs) and cellular metabolism. Differential expression for 20 out of 789 genes were confirmed by quantitative reverse transcription-PCR (qRT-PCR). A bioinformatics tool (Ingenuity Pathway Analysis) used to analyze biological functions and pathways on the group of 789 differentially expressed genes revealed that 21 possible gene networks with intermolecular connections among 275 functionally identified genes. These 275 genes were classified into a number of functional groups that included cancer, genetic disorder, cellular growth and proliferation, and cell death. Conclusion The results of this study provide comprehensive knowledge on global gene expression, and biological functionalities of differentially expressed genes in chicken embryo lung cells in response to ILTV infections.

Abstract Background A variety of techniques have been described which introduce scarless, site-specific chromosomal mutations. These techniques can be applied to make point mutations or gene deletions as well as insert heterologous DNA into bacterial vectors for vaccine development. Most methods use a multi-step approach that requires cloning and/or designing repeat sequences to facilitate homologous recombination. We have modified previously published techniques to develop a simple, efficient PCR-based method for scarless insertion of DNA into Salmonella enteritidis chromosome. Results The final product of this mutation strategy is the insertion of DNA encoding a foreign epitope into the S. enteritidis genome without the addition of any unwanted sequence. This experiment was performed by a two-step mutation process via PCR fragments, Red recombinase and counter-selection with the I-SceI enzyme site. First, the I-SceI site and kanamycin resistance gene were introduced into the genome of cells expressing Red recombinase enzymes. Next, this sequence was replaced by a chosen insertion sequence. DNA fragments used for recombination were linear PCR products which consisted of the foreign insertion sequence flanked by homologous sequences of the target gene. Described herein is the insertion of a section of the M2e epitope (LM2) of Influenza A virus, a domain of CD154 (CD154s) or a combination of both into the outer membrane protein LamB of S. enteritidis. Conclusion We have successfully used this method to produce multiple mutants with no antibiotic gene on the genome or extra sequence except those nucleotides required for expression of epitope regions. This method is advantageous over other protocols in that it does not require cloning or creating extra duplicate regions to facilitate homologous recombination, contains a universal construct in which an epitope of choice can be placed to check for cell surface expression, and shows high efficiency when screening for positive mutants. Other opportunities of this mutational strategy include creating attenuated mutants and site-specific, chromosomal deletion mutations. Furthermore, this method should be applicable in other gram-negative bacterial species where Red recombinase enzymes can be functionally expressed.

Oxidative stress is an unavoidable consequence of aerobic metabolism. Whereas high amounts of mitochondrial reactive oxygen species (ROS) can cause oxidation, low levels play important roles in signal transduction. In a Pedigree male (PedM) broiler model of feed efficiency (FE), the low FE phenotype was characterized by increased ROS in isolated mitochondria (muscle, liver, and duodenum) with a pervasive protein oxidation in mitochondria and tissues. Subsequent proteogenomic studies in muscle revealed evidence of enhanced mitoproteome abundance, enhanced mitochondrial phosphocreatine shuttling expression, and enhanced ribosome assembly in the high FE phenotype. Surprisingly, an enhanced infrastructure would foster greater repair of damaged proteins or organelles through the autophagy and proteosome pathways in the high FE phenotype. Although protein and organelle degradation, recycling, and reconstruction would be energetically expensive, it is possible that energy invested into maintaining optimal function of proteins and organelles contributes to cellular efficiency in the high FE phenotype. New findings in mitochondrial physiology have been reported in the last several years. Reverse electron transport (RET), once considered an artifact of in vitro conditions, now is recognized to play significant roles in inflammation, ischemia–reperfusion, muscle differentiation, and energy utilization. A topology of ROS production indicates that ROS derived from Complex I of the respiratory chain primarily causes oxidation, whereas ROS generated from Complex III are primarily involved in cell signaling. It is also apparent that there is a constant fission and fusion process that mitochondria undergo that help maintain optimal mitochondrial function and enables mitochondria to adjust to periods of nutrient limitation and nutrient excess. Understanding the balancing act that mitochondria play in health and disease will continue to be a vital biological component in health-production efficiency and disease in commercial animal agriculture. [ABSTRACT FROM AUTHOR]

Oxidative stress is an unavoidable consequence of aerobic metabolism. Whereas high amounts of mitochondrial reactive oxygen species (ROS) can cause oxidation, low levels play important roles in signal transduction. In a Pedigree male (PedM) broiler model of feed efficiency (FE), the low FE phenotype was characterized by increased ROS in isolated mitochondria (muscle, liver, and duodenum) with a pervasive protein oxidation in mitochondria and tissues. Subsequent proteogenomic studies in muscle revealed evidence of enhanced mitoproteome abundance, enhanced mitochondrial phosphocreatine shuttling expression, and enhanced ribosome assembly in the high FE phenotype. Surprisingly, an enhanced infrastructure would foster greater repair of damaged proteins or organelles through the autophagy and proteosome pathways in the high FE phenotype. Although protein and organelle degradation, recycling, and reconstruction would be energetically expensive, it is possible that energy invested into maintaining optimal function of proteins and organelles contributes to cellular efficiency in the high FE phenotype. New findings in mitochondrial physiology have been reported in the last several years. Reverse electron transport (RET), once considered an artifact of in vitro conditions, now is recognized to play significant roles in inflammation, ischemia–reperfusion, muscle differentiation, and energy utilization. A topology of ROS production indicates that ROS derived from Complex I of the respiratory chain primarily causes oxidation, whereas ROS generated from Complex III are primarily involved in cell signaling. It is also apparent that there is a constant fission and fusion process that mitochondria undergo that help maintain optimal mitochondrial function and enables mitochondria to adjust to periods of nutrient limitation and nutrient excess. Understanding the balancing act that mitochondria play in health and disease will continue to be a vital biological component in health-production efficiency and disease in commercial animal agriculture. [ABSTRACT FROM AUTHOR]