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The enclosed multistory poultry housing is a type of poultry enclosure widely used in industrial caged chicken breeding. Accurate identification and detection of the comb and eyes of caged chickens in poultry farms using this type of enclosure can enhance managers' understanding of the health of caged chickens. However, the accuracy of image detection of caged chickens will be affected by the enclosure's entrance, which will reduce the precision. Therefore, this paper proposes a cage-gate removal algorithm based on big data and deep learning Cyclic Consistent Migration Neural Network (CCMNN). The method achieves automatic elimination and restoration of some key information in the image through the CCMNN network. The Structural Similarity Index Measure (SSIM) between the recovered and original images on the test set is 91.14%. Peak signal-to-noise ratio (PSNR) is 25.34dB. To verify the practicability of the proposed method, the performance of the target detection algorithm is analyzed both before and after applying the CCMNN network in detecting the combs and eyes of caged chickens. Different YOLOv8 detection algorithms, including YOLOv8s, YOLOv8n, YOLOv8m, and YOLOv8x, were used to verify the algorithm proposed in this paper. The experimental results demonstrate that compared to images without CCMNN processing, the precision of comb detection of caged chickens is improved by 11, 11.3, 12.8, and 10.2%. Similarly, the precision of eye detection for caged chickens is improved by 2.4, 10.2, 6.8, and 9%. Therefore, more complete outline images of caged chickens can be obtained using this algorithm and the precision in detecting the comb and eyes of caged chickens can be enhanced. These advancements in the algorithm offer valuable insights for future poultry researchers aiming to deploy enhanced detection equipment, thereby contributing to the accurate assessment of poultry production and farm conditions. [ABSTRACT FROM AUTHOR]

Protein arginine methyltransferase 5 (PRMT5), a type II arginine methyltransferase, controls arginine dimethylation of a variety of substrates. While many papers have reported the function of mammalian PRMT5, it remains unclear how PRMT5 functions in chicken cells. In this study, we found that chicken (ch) PRMT5 is widely expressed in a variety of chicken tissues and is distributed in both the cytoplasm and the nucleus. Ectopic expression of chPRMT5 significantly suppresses chIFN-β activation induced by chMDA5. In addition, a prmt5 gene-deficient DF-1 cell line was constructed using CRISPR/Cas9. In comparison with the wild-type cells, the prmt5−/− DF-1 cells displays normal morphology and maintain proliferative capacity. Luciferase reporter assay and overexpression showed that prmt5−/− DF-1 cells had increased IFN-β production. With identified chicken PRMT5 and CRISPR/Cas9 knockout performed in DF-1 cells, we uncovered a functional link of chPRMT5 in suppression of IFN-β production and interferon-stimulated gene expression. [ABSTRACT FROM AUTHOR]

To confirm the role of high-pressure processing in enhancing the quality of Eucheuma spinosum chicken breast batters, low-field nuclear magnetic resonance, scanning electron microscopy and Raman spectroscopy were used to explore the effect of E. spinosum and high-pressure processing on water migration, protein conformation, and microstructure in chicken breast batters. The water-holding capacity, surface hydrophobicity, and reactive sulfhydryl group content significantly increased as the pressure increased (0.1 to 300 MPa), while the peak ratio of non-flowable water (T 22) decreased (P > 0.05). The secondary structure composition changed significantly, and the β -sheet, β -turn, and random coil content significantly increased (P < 0.05) as the α -helix content decreased. The –OH stretching vibration (3,100 to 3,500 cm−1) was shifted to higher wavenumbers, and the number of hydrogen bonds in each water molecule increased. The scanning electron microscopy images reveal that proper pressure produced a dense network structure with small cavities. Moreover, these characteristics were further enhanced when E. spinosum was added from 0 to 0.4%. Overall, this paper could provide crucial theoretical support for the application of high-pressure processing of low-salt seaweed chicken breast. [ABSTRACT FROM AUTHOR]

Broiler breeders are subjected to feed restriction programs to control excessive growth. However, current levels of feed restriction and concomitant growth restriction are becoming severe, raising welfare and suboptimal reproductive performance concerns in underfed breeders. To circumvent the issue, our previous studies investigated the effects of new strategic growth curves, with various degrees of relaxed growth restrictions, on broiler breeders and their progeny's performance. The broiler breeder study was conducted with 40 Ross 708 broiler breeder pullets reared on 1 of 10 target growth trajectories using a precision feeding (PF) system. The growth trajectories were designed with 2 levels of the amount of prepubertal BW gain and 5 levels of pubertal growth timing. The prepubertal BW gain (g 1) was estimated from the breeder-recommended standard BW gain (Standard g 1) target, or 10% higher (High g 1). The pubertal growth timing (I 2) was advanced such that it happened at I 2 -0% = 22.29 wk, I 2 -5% = 21.16 wk, I 2 -10% = 20.05 wk, I 2 -15% = 18.94 wk, I 2 -20% = 17.82 wk of age. Two broiler experiments with different maternal ages (35 and 42 wk) were conducted as the extension of the breeder experiment to evaluate the intergenerational effects of a reduced degree of maternal prepubertal phase growth restriction and earlier maternal pubertal phase growth on offspring growth and development. The current paper investigated the economic aspects of implementing the growth curves using the partial budget analysis. Increasing prepubertal BW gain by 10% and advancing the pubertal growth phase by 20% (scenario 10) could increase margin over feed and chick cost for the hatching egg producers by CDN$1.97/hen. For broiler chicken supply chain as a whole, the highest differential margin over feed and chick cost was for maternal growth scenario 10 from 42-wk-old hens. The latter margin over feed and chick cost was greater than that of breeder-recommended maternal growth (from 35-wk-old hens) by $0.1053/kg live chicken under the current economic situation. [ABSTRACT FROM AUTHOR]

Wingless-2 (wg-2) is an autosomal recessive mutation in chicken that results in an embryonic lethal condition. Affected individuals exhibit a multisystem syndrome characterized by absent wings, truncated legs, and craniofacial, kidney, and feather malformations. Previously, work focused on phenotype description, establishing the autosomal recessive pattern of Mendelian inheritance and placing the mutation on an inbred genetic background to create the congenic line UCD Wingless-2.331. The research described in this paper employed the complementary tools of breeding, genetics, and genomics to map the chromosomal location of the mutation and successively narrow the size of the region for analysis of the causative element. Specifically, the wg-2 mutation was initially mapped to a 7 Mb region of chromosome 12 using an Illumina 3 K SNP array. Subsequent SNP genotyping and exon sequencing combined with analysis from improved genome assemblies narrowed the region of interest to a maximum size of 227 kb. Within this region, 3 validated and 3 predicted candidate genes are found, and these are described. The wg-2 mutation is a valuable resource to contribute to an improved understanding of the developmental pathways involved in chicken and avian limb development as well as serving as a model for human development, as the resulting syndrome shares features with human congenital disorders. [ABSTRACT FROM AUTHOR]

The year 2014 marked the tenth anniversary since the sequence of the chicken genome was published. Two other publications occurred during that time frame in different disciplines, and all 3 have affected poultry scientists. The purpose of this paper is to briefly review 2 publications that are better known to those in animal agriculture. The third paper will be addressed in more detail because it is one that many in poultry science probably have not read. The subject matter involves the avian brain and its future impact and is related to an announcement made by the president of the United States in April 2013. Due to the recent, rapid advances in the understanding of the vertebrate brain and behavior, a national goal was announced by President Obama to map the human brain in more detail than ever before to accelerate the understanding of brain function in health and disease. The main objective is to review the third paper published a decade ago to show that it laid the foundation for the chicken and other avian species to serve as relevant animal models to advance the understanding of the human brain. Emphasis will be placed on the forebrain. The overall goal is to show that the brain of birds is not that different from the mammalian brain and therefore can serve as an excellent comparative biomodel to understand fundamental principles of brain structure and function. [ABSTRACT FROM AUTHOR]

Setting directions and goals for animal production systems requires the integration of information achieved through internal and external processes. The importance of stakeholder input in setting goals for sustainable animal production systems should not be overlooked by the agricultural animal industries. Stakeholders play an integral role in setting the course for many aspects of animal production, from influencing consumer preferences to setting public policy. The Socially Sustainable Egg Production Project (SSEP) involved the development of white papers on various aspects of egg production, followed by a stakeholder workshop to help frame the issues for the future of sustainable egg production. Representatives from the environmental, food safety, food retail, consumer, animal welfare, and the general farm and egg production sectors participated with members of the SSEP coordination team in a 1.5-d workshop to explore socially sustainable egg production. This paper reviews the published literature on values integration methodologies and the lessons learned from animal welfare assessment models. The integration method used for the SSEP stakeholder workshop and its outcome are then summarized. The method used for the SSEP stakeholder workshop can be used to obtain stakeholder input on sustainable production in other farm animal industries. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to perform a meta-analysis to compare the biological efficiency of DL-methionine with methionine-hydroxy-analogue- free-acid in broiler chickens. A database was developed which contained dose-response studies of these 2 methionine sources. Criteria for entry into the database were defined before the meta-analysis was initiated. Data from 46 dose-response experiments, extracted from a total of 27 peer-reviewed papers, were used for the analysis with the Statistical Analysis System. Initially, the NUN procedure was applied to fit an exponential model of the form y = α + β*[1 - exp (-γ*dose)] + e. Thereafter, meta-analysis was conducted by means of nonlinear mixed models, which were fitted by a full maximum likelihood method as implemented in the NLMIXED procedure. The nonlinear model used for the analysis allowed for separate plateaus or different efficiencies of the methionine sources. Mixed modeling was applied to account for heterogeneity among the studies in all regression parameters for both sources of methionine via random effects. Statistical hypotheses were tested by the asymptotic Wald test. In addition, potential co-variables were tested for inclusion as linear regressors for the nonlinear model parameters. In conclusion, the null hypothesis of equal plateaus of the 2 methionine sources was not rejected. The analyses of the response variables average daily gain (ADG) and gain to feed ratio (GF) showed a highly significant difference between the tested methionine sources. The covariate age at start of experiment significantly affected the intercept term a for the response variables ADG and GF, respectively. The meta-analysis showed that biological efficiencies of DL-methionine-hydroxy-analogue-free-acid were 81 and 79% of the values for DL-methionine, on an equimolar basis, for ADG and GF, respectively. [ABSTRACT FROM AUTHOR]

The University of Georgia maintains two meat-type chicken control strains: the Athens Random Bred (ARB) and the Athens Canadian Random Bred (ACRB). The Athens Random Bred was developed from colored plumage commercial meat chicken strains in 1956. The ACRB is a replicate population of the Ottawa Meat Control strain which was developed in 1955 from white plumage commercial meat-type chickens. These genetic lines have been extremely valuable research resources and have been used extensively to provide comparative context to modern meat-type strains. The ACRB may be the oldest pedigreed control commercial meat-type chicken still in existence today. This paper reviews the history of the breed backgrounds for both control populations and reviews research utilizing the ACRB. [ABSTRACT FROM AUTHOR]

Levels of natural antibodies (NAb) binding keyhole limpet hemocyanin (KLH) in layers were shown to be heritable and to be potential indicative parameters for survival. A proportion of NAb are directed to self-molecules, or slightly changed selfmolecules (neo-epitopes), labeled as natural autoantibodies (NAAb). It is unknown whether the levels of NAAb are heritable and genetically correlated. In this paper, we estimated genetic parameters in plasma of healthy layers for IgM and IgG antibodies binding ovalbumin (OVA), myosin (MYO), cardiolipin (CAR), lysozyme (LYS), and the model antigen keyhole limpet hemocyanin (KLH). A linear animal model was used to estimate (co)variance components, heritabilities, and correlations. The estimates of heritabilities ranged from 0.10 to 0.17 for IgM, and 0.02 to 0.11 for IgG, respectively. For both IgM and IgG, high genetic correlations were observed between levels of NAAb binding autoantigens and NAb binding KLH, except for IgG binding KLH and LYS, for which a low genetic correlation was found. Low to moderate phenotypic correlations were found between NAAb and NAb. In addition, significant maternal environmental effects of 0.03, 0.07, and 0.04 were observed for IgM binding OVA, LYS, and KLH, respectively. Results from this study indicated that NAAb or NAb levels in plasma were heritable and could provide tools to identify the health status of birds. [ABSTRACT FROM AUTHOR]

A study with a 2 × 3 × 2 factorial arrangement was conducted to determine the effects of 2 dietary protein levels (high = CPh and low = CPl) during rearing, 3 dietary energy levels (3,000, MEh1; 2,800, MEs1; and 2,600, MEl1, kcal/kg AMEn, respectively) during the first phase of lay, and 2 dietary energy levels (2,800, MEs2; and 3,000, MEh2, kcal/kg AMEn, respectively) during the second phase of lay on body composition and reproduction in broiler breeders. No meaningful interactions for energy and protein treatments within the different phases of the study were found and, therefore, this paper focusses on the main effects. Pullets fed the CPl diet had a 12.8% higher feed intake, 14% lower breast muscle, and 97% higher abdominal fat pad portion at 22 wk age. The increased abdominal fat pad and decreased breast muscle of the CPl compared to the CPh birds increased hatchability during the first phase of lay, due to a decreased embryonic mortality between d 10 to 21 of incubation, and increased egg production during the second phase of lay. Feeding birds the MEh1 and MEl1 diets slightly decreased egg production compared to the MEs1 birds. Birds fed the MEh1 diet showed a higher mortality compared to the birds fed the MEs1 and MEl1 diets. Feeding birds the MEh2 diet did not affect egg production, increased hatchability of fertile eggs, decreased embryonic mortality between d 3 to 21 of incubation, and increased the number of first-grade chicks. It was concluded that a low-protein diet during rearing changed body composition with positive effects on incubation traits during the first phase of lay and improved egg production during the second phase of lay in broiler breeders. A high-energy or low-energy diet compared to a standard diet during the first phase of lay slightly decreased total and settable egg numbers while a high-energy diet during the second phase of lay increased hatchability and number of saleable chicks. [ABSTRACT FROM AUTHOR]

Natural antibodies (NAb) are an important component of the first line of immune defense. Selective breeding for enhanced NAb levels in chickens may improve general disease resistance. It is unknown what the consequences of selection for NAb will be on the productive performance of laying hens. In this paper we describe the genetic relations between NAb titers binding keyhole limpet hemocyanin at 19 wk age and production traits in a white purebred leghorn chicken line observed in several time periods. A linear animal model was used to estimate (co)variance components, heritabilities, and correlations. Negative genetic correlations were found between egg weight and NAb titers, and between egg breaking strength and NAb titers. Positive genetic correlations were found between the feed conversion ratio (consumed feed/egg mass produced) and NAb titers, and egg production and NAb titers. Negative phenotypic correlations were found between body weight and NAb titers, between egg weight and NAb titers, and between egg breaking strength and NAb titers. Positive phenotypic correlations were found between egg production and NAb titers, and feed conversion ratio and NAb titers. In general, phenotypic correlations were more often significant, but less pronounced than genetic correlations. Other production traits were not found to be significant related to NAb titers. These findings suggest that there is a genetic tradeoff between levels of immunity and some production traits, although the underlying mechanism(s) remain(s) unclear. The results suggest possible consequences for production efficiency as a result of selective breeding for improved general disease resistance by natural antibodies. [ABSTRACT FROM AUTHOR]

Intensive genetic selection of broiler breeders and layer hens for economically important production traits, which has been carried out for almost a century, resulted in considerable differences in the mechanisms of growth and development and, thus, in avian metabolism, both during embryogenesis and after hatching. Selection for meat production (broiler breeders) and eggs (layer hens) led to increased productivity but also brought about metabolic disorders. That intensive genetic selection of broiler breeders and layer hens is effective is seen, for example, in the differences in growth and development, metabolism of the yolk sac, hormones and lipids, gas exchange, and thermogenesis. Due to genetic proximity and different developmental mechanisms in broiler breeders and layer hens, avian embryos and chicks serve as excellent models for fundamental scientific research. This review paper discusses the consequences of different growth rates as a result of long-term genetic selection on embryonic development and metabolic rate of broilers and layers. The evidence presented herein indicates that it would be worth comparing these issues in a meta-analysis. [ABSTRACT FROM AUTHOR]

"Continuous feeding of low concentrations of sulfaquinoxaline for the control of coccidiosis in poultry" by L. C. Grumbles, J. P. Delaplane, and T. C. Higgins [Poult. Sci. (1948) 27:605-608] was the first paper to demonstrate that it was possible to control coccidiosis by the continuous inclusion of a low level of a drug in the feed of chickens. The principle involved (prevention or prophylaxis) has had a profound impact on our ability to grow chickens and turkeys under intensive conditions. Indeed, it is possible that the modern poultry industry could never have developed to its present extent without the advent of drugs used prophylactically to control coccidiosis. One particular insight was that use of a compound in this manner did not necessarily prevent the acquisition of immunity, an important principle that helpsexplain the continued efficacy of ionophorous antibiotics used today. The significance of this work to the poultry industry and individuals involved in research, whether employed by government, academia, or pharmaceutical companies, cannot be overstated. Economic benefits, in terms of improved productivity, have been demonstrated in numerous studies published in Poultry Science. In addition, the livelihoods of many poultry farmers have been helped by the control of a disease that in the past caused substantial morbidity and mortality in their flocks. The paper is brief and contains no critical science involving novel procedures but has had a profound influence on the health of poultry for the last 6 decades. For this reason, it is nominated as a landmark contribution from the first 100 yr of Poultry Science. [ABSTRACT FROM AUTHOR]

A meta-analysis was carried out to study the association of mycotoxins with performance, productive indices, and organ weights in broilers. Ninety-eight papers published between 1980 and 2009 were used, totaling 1,401 diets and 37,371 animals. Meta-analysis followed 3 sequential analyses: graphical, correlation, and variance-covariance. The mycotoxin presence in diets reduced (P < 0.05) feed intake by 12% and weight gain by 14% compared with control group. Ochratoxins and aflatoxins were the mycotoxins with the greatest effect on feed intake and bird growth, reducing (P < 0.05) feed ingestion by 17 and 11%, respectively, and weight gain by 20 and 11%, respectively. The mycotoxin concentration in diets and the animal age at challenge were the variables that more improved the coefficient of determination for equations to estimate mycotoxin effect on weight gain. The mycotoxin effect on growth proved to be greater in young poultry. The residual analysis revealed that 65% of the variation in weight gain was explained by feed intake. The variation in weight gain of challenged broilers in relation to nonchallenged broilers was also influenced by ingestion of nutrients such as protein and methionine. Mortality was 8.8 and 2.8 times greater (P < 0.05) in groups that received diets with deoxynivalenol and aflatoxins, respectively. Mycotoxins also increased (P < 0.05) the relative weight of liver by 15%, of kidneys by 11%, of lungs by 9%, and of gizzard by 3%. Mycotoxins influenced broiler performance, productive indices, and organ weights. However, the magnitude of the effects varied with type and concentration of mycotoxin, animal age, and nutritional factors. [ABSTRACT FROM AUTHOR]

It is generally accepted that the intestinal microbiota plays an important role in sustaining health and productivity of animals. Chlorella vulgaris, a naturally occurring green microalga, is believed to influence performance and health, including bird reproduction and egg quality. The nutritive value of open or indoor cultured C. vulgaris depends upon the technological process used to treat the algal mass. In the present paper, it is presented and discussed how 2 differentially processed C. vulgaris powders (spray-dried: SDCV; bullet-milled and spray-dried: BMSD-CV) affected crop and cecal microbiota in laying hens. Polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA gene fragments was applied. The diversity of the crop universal bacterial DGGE fingerprints was not affected (6.4 ± 1.65, 5.4 ± 1.19, and 5.5 + 1.35 in the control, SD-CV, and BMSD-CV, respectively). Most of the bands from the corresponding positions in the gels were closely related to Lactobacillus sp. The DGGE fingerprints of V2-V3 fragments of 16S rRNA of crop lactobacilli had lower diversity in the control hens (8.7 ± 1.22) than in the SD-CV (9.2 ± 1.77) and BMSD-CV (9.9 ± 1.88); thus, feeding C. vulgaris resulted in increased lactobacilli diversity in crop. A band closely related to Lactobacillus ingluviei was present in 9 out of 12 hens in the control group but in only 1 bird in the SD-CV and in 5 out of 11 birds in the BMSD-CV, suggesting a negative effect of C. vulgaris on this lactobacillus. Feeding C. vulgaris to laying hens also resulted in increased bacterial community diversity in the ceca. No effect of the technological processing of the microalgae on the microbial diversity could be observed. The diversity of the ceca universal bacterial DGGE fingerprints was lower in the control group than in the SD-CV and BMSD-CV (5.6 ± 1.72 vs. 9.16 ± 2.64 and 9.31 ± 2.41, respectively). Most of the sequences retrieved from the DGGE bands formed ceca that were closely related to Ruminococcaceae, Lachnospiraceae, and lactobacilli, giving further insight into still poorly discovered intestinal microbiota of laying hens. [ABSTRACT FROM AUTHOR]

Poultry has commonly been considered highly susceptible to aflatoxins. However, among domestic fowl there is wide variability in specific species sensitivity to these mycotoxins. Comparative toxicological studies in avian species have shown that ducklings and turkey poults are the most sensitive species to aflatoxins, quails show intermediate sensitivity, whereas chickens are the most resistant. Hormesis is a dose-response phenomenon characterized by low-dose stimulation and high-dose inhibition. The low-dose stimulation is typically maximal at only about 30 to 60% greater than controls. Hormesis has been noted in regards to changes in body weight in numerous studies, including those per- formed for the US National Toxicology Program, with over 50 chemicals. The present paper assesses how relatively low levels of aflatoxin consumption in feed may affect the growth rate of chickens. In general, multiple independent investigations have shown that such aflatoxin consumption affects growth in a hormetic-like biphasic maimer with a low dose stimulation and a high dose inhibition. Such observations were then generalized to other toxic agents and animal models, suggesting that low doses of stressor agents induce adaptive responses as reflected in accelerated growth rates. The implications of such hormetic dose responses are briefly discussed. [ABSTRACT FROM AUTHOR]

Since the sequencing of the genome and the development of high-throughput tools for the exploration of functional elements of the genome, the chicken has reached model organism status. Functional genomics focuses on understanding the function and regulation of genes and gene products on a global or genome-wide scale. Systems biology attempts to integrate functional information derived from multiple high-content data sets into a holistic view of all biological processes within a cell or organism. Generation of a large collection (∼600K) of chicken expressed sequence tags, representing most tissues and developmental stages, has enabled the construction of high-density microarrays for transcriptional profiling. Comprehensive analysis of this large expressed sequence tag collection and a set of ∼20K full-length cDNA sequences indicate that the transcriptome of the chicken represents approximately 20,000 genes. Furthermore, comparative analyses of these sequences have facilitated functional annotation of the genome and the creation of several bioinformatic resources for the chicken. Recently, about 20 papers have been published on transcriptional profiling with DNA microarrays in chicken tissues under various conditions. Proteomics is another powerful high-throughput tool currently used for examining the dynamics of protein expression in chicken tissues and fluids. Computational analyses of the chicken genome are providing new insight into the evolution of gene families in birds and other organisms. Abundant functional genomic resources now support large-scale analyses in the chicken and will facilitate identification of transcriptional mechanisms, gene networks, and metabolic or regulatory pathways that will ultimately determine the phenotype of the bird. New technologies such as marker-assisted selection, transgenics, and RNA interference offer the opportunity to modify the phenotype of the chicken to fit defined production goals. This review focuses on functional genomics in the chicken and provides a road map for large-scale exploration of the chicken genome. [ABSTRACT FROM AUTHOR]

A primary goal in the assessment of structural variation in the avian genome is to understand the relationship of this variation with biodiversity and with biological performance. To develop such knowledge, certain essential tools are needed. One set of tools includes the laboratory techniques used to assess molecular genetic variation. The current time is a transitional one for this field, in that the recently sequenced chicken genome will add significantly to the portfolio of existing methods used to identify molecular markers. To most efficiently discover marker-trait associations, the experimental mapping populations must be appropriately designed and the relevant statistical analyses applied. This paper reviews methods for assessment of molecular markers in poultry and their use in the characterization of avian biodiversity and in studies to identify marker associations with biological traits, including important considerations of population structure and statistical analysis. [ABSTRACT FROM AUTHOR]

The chicken has a proud history, both in genetic research and as a source of food. Here we attempt to provide an overview of past contributions of the chicken in both arenas and to link those contributions to the near future from a genetic perspective. Companion articles will discuss current poultry genetics research in greater detail. The chicken was the first animal species in which Mendelian inheritance was demonstrated. A century later, the chicken was the first among farm animals to have its genome sequenced. Between these firsts, the chicken remained a key organism used in genetic research. Breeding programs, based on sound genetic principles, facilitated the global emergence of the chicken meat and egg industries. Concomitantly, the chicken served as a model whose experimental populations and mutant stocks were used in basic and applied studies with broad application to other species, including humans. In this paper, we review some of these contributions, trace the path from the origin of molecular genetics to the sequence of the chicken genome, and discuss the merits of the chicken as a model organism for furthering our understanding of biology. [ABSTRACT FROM AUTHOR]

Methods for mapping QTL are actively used in the chicken to identify chromosomal regions contributing to variation in traits related to growth, disease resistance, egg production, behavior, and metabolic parameters. However, higher-resolution mapping and better knowledge of the genetic architecture underlying QTL are needed for successful application of this information into breeding programs. Therefore, this paper summarizes and integrates original, primary QTL studies in the chicken to identify basic information on the genetic architecture of quantitative traits in chickens. The results of this review show several instances of consensus of QTL locations for similar traits from independent studies. Furthermore, the consensus of QTL location for different traits and evidence for QTL with parent-of-origin effect, transgressive alleles, epistatic QTL, and QTL × sex interaction in chicken are presented and discussed. This information can be helpful in identifying genes or mutations underlying the QTL and in the application of genomic information in marker-assisted breeding programs. [ABSTRACT FROM AUTHOR]

Experiments were conducted to estimate daily N maintenance requirements (NMR) and the genetic potential for daily N deposition (NDmaxT) in fast-growing chickens depending on age and sex. In N-balance studies, 144 male and 144 female chickens (Cobb 500) were utilized in 4 consecutive age periods (I: 10 to 25 d; II: 30 to 45 d; III: 50 to 65 d; and IV: 70 to 85 d). The experimental diets contained high-protein soybean meal and crystalline amino acids as protein sources and 6 graded levels of protein supply (N1 = 6.6%; N2 = 13.0%; N3 = 19.6%; N4 = 25.1%; N5 = 31.8%; and N6 = 37.6% CF in DM). The connection between N intake and total N excretion was fitted for NMR determination by an exponential function. The average NMR value (252 mg of N/BWkg0.67 per d) was applied for further calculation of NDmaxT as the threshold value of the function between N intake and daily N balance. For estimating the threshold value, the principle of the Levenberg-Marquardt algorithm within the SPSS program (Version 11.5) was applied. As a theoretical maximum for NDmaxT, 3,592, 2,723, 1,702, and 1,386 mg of N/BWkg067 per d for male and 3,452, 2,604, 1,501, and 1,286 mg of N/BWkg067 per d for female fast-growing chickens (corresponding to age periods I to IV) were obtained. The determined model parameters were the precondition for modeling of the amino acid requirement based on an exponential N-utilization model and depended on performance and dietary amino acid efficiency. This procedure will be further developed and applied in the subsequent paper. [ABSTRACT FROM AUTHOR]

Modeling of broiler chicken supply-chain economics depends on robust biological models of growth and yield of broiler chickens. In this paper, 8 dynamic nonlinear broiler carcass and carcass part yield models were evaluated statistically for their suitability for predicting weights of carcass parts. The analysis employed 4 sigmoidal (S) models (Gompertz, modified Gornpertz, Richards, and Lopez) describing carcass part weight as a function of age, as well as 3 diminishing returns (DR) models (Lopez, Mitscherlich, and log linear), and a log-linear proportional yield (PY) model, which describe carcass part yield and weight, respectively, as a proportion of feather- and fat-free empty body mass (FFEBM). Three S models with a flexible point of inflection were better able to predict carcass part weights than a fixed point of inflection Gompertz model and, in general, the DR models. The log-linear models were the only models that converged in 100% of the evaluations. The allometric PY model predicted weights for most carcass parts with the smallest degree of error and with substantially less bias than the DR log-linear model. Estimates of the coefficients for the log-linear PY model are included for 12 key carcass parts. Estimates of carcass chemical composition are presented for the log-linear PY model. [ABSTRACT FROM AUTHOR]

Presented is an overview of the thesis of this symposium with a snapshot summation of the papers presented, including modest critiques and suggestions for future efforts. [ABSTRACT FROM AUTHOR]

An abstract of the paper "Effects of Spray Characteristics on Application of Avian Vaccines," by J. L. Purswell and colleagues is presented.

The article presents an abstract of the research paper "Effects of alternatives of molting on bird well-being," by D. Lay and colleagues.

The article presents an abstract of the research paper "Essential oils can substitute growth promoter antibiotics in broiler chicken," by N. Mathlouti and colleagues.

Poultry science has entered a new era with the completion of a century of investigative studies in chicken genetics, sequencing of the chicken genome, application of genomic tools into systems biology studies, and rapid advances in the development of the statistical theory for application of molecular genetic information in commercial breeding programs. This perspectives paper sets the context for the accompanying series of reviews on chicken genetics and genomics, introduces important issues in the field of poultry molecular genetics, and briefly describes the topics of each of the reviews. [ABSTRACT FROM AUTHOR]

The article presents an abstract of the research paper "Digestible threonine requirements for broiler chickens during pre-initial phase," by F.G.P. Costa and colleagues.

An abstract of the paper "Effect of Deboning Time and Cold Storage on Water-Holding Capacity of Chicken Breast Meat," by H. Zhuang abd E. M. Savage is presented.

An abstract of the paper "Evaluation of Probiotic and Phytogenetic Products on the Development of Necrotic Enteritis in Poultry," by J. L. McReynolds and colleagues is presented.

An abstract of the paper "Fungi Collected From Market-Age Broilers Under Commercial Conditions," by J. A. Byrd and colleagues is presented.

An abstract of the paper "Role of Different Genes in the Pathogenesis of H5N1 Avian Influenza Virus in Chickens," by J. L. Wasilenko and colleagues is presented.

The article presents an abstract of the research paper "Texture of frankfurters manufactured from chicken thigh and enriched with plant-based fat sources," by R. Currie and colleagues.

The article presents an abstract of the research paper "Effects of replacing the antibiotic growth promoter by whole cells or cell wall components from Saccharomyces cerevisiae in the diet of broiler chickens," by M.L. Angeles and colleagues.

The article presents an abstract of the research paper "The effect of dietary protein level and digestibility and Clostridium perfringens infection on the growth performance of broiler chickens," by G.P. Widyaratne and colleagues.

The article presents an abstract of the research paper "Growth performance of broiler chickens fed diets containing shea nut (Vitellaria paradoxa, Gaertn.) meal fermented with Aspergilus niger," by H. K. Dei and colleagues.

The article presents an abstract of the research paper "Bacterial populations of broiler chickens fed yeast products in place of antibiotics," by K. Budgell and colleagues.

The article presents an abstract of the research paper "Influence of micronization (fine grinding) of soybean meal and fullfat soybean on ileal digestibility of amino acids in broiler chickens," by D.G. Valencia and colleagues.

The article presents an abstract of the research paper "Effect of dietary probiotic and/or prebiotic on the humoral immune response of Ross broiler chickens," by H. Ziaie and colleagues.

The article presents an abstract of the research paper "Short-term effects of triiodothyronine on hypothyroid chickens," by R.W. Rosebrough and colleagues.

The article presents an abstract of the research paper "Changes of biochemical parameters and enzymes activities in broiler chickens with cold induced ascites," by A.G. Golian and colleagues.

The article presents an abstract of the research paper "Reactive oxygen species production of chicken heterophils and peripheral blood mononuclear cells in response to the Dectin-1 specific agonist, curdlan," by J. Nerren and M. Kogut.

The article presents an abstract of the research paper "Expression of Antimicrobial Peptide Genes in Chicken Cecal Tonsils After Treatment With Probiotics and Challenge With Salmonella," by M.R. Akbari and colleagues.

The article presents an abstract of the research paper "Influence of In-Feed Virginiamycin on the Systemic and Mucosal Antibody-Mediated Immune Response of Chickens," by J.T. Brisbin and colleagues.

The article presents an abstract of the research paper "Virtual Chicken and Other Virtual Teaching Tools," by P.A. Curtis and colleagues.

The article presents an abstract of the research paper "Effect of Feed Restriction on Core Body Temperature Dynamics in Meat-Type Chickens," by R.A. Renema and colleagues.

The article presents an abstract of the research paper "Improvement in hot (dry) breast meat yield of broiler chickens with dietary AZOMITE®, natural mineral supplement, as shown by statistical meta-analyses of data from 13 contract research trials and 10 integrator field trials," by W. Emerson and colleagues.

The article presents an abstract of the research paper "A new cytogenetic model for the order of the nucleolus organizer region (NOR), major histocompatibility complex (MHC) -B, and -Y on microchromosome 16 in chicken," by M.E. Delany and colleagues.

The article presents an abstract of the research paper "Molecular Analysis of Microbial Community Structure in the Chicken Ileum Following Organic Acid Supplementation," by G. Nava and colleagues.