White Leghorn Research Articles

Effect of enzyme-modified yeast products on Salmonella Enteritidis colonization in different organs of laying hens

A study was conducted to assess the effectiveness of yeast-derived products in the recovery of Salmonella Enteritidis (SE) in White Leghorns. A total of thirty-two hens at 38 weeks of age were challenged both orally (OR) and intracloacally (IC) with nalidixic acid resistant SE (SE NAR ). Hens were individually housed in conventional wire laying cages and randomly allocated to four treatments (T) with eight hens per replicate: 1) No SE NAR challenge (T1; basal diet), 2) SE NAR challenge (T2; basal diet), 3) SE NAR challenge: basal diet with a blend of Saccharomyces- Torula yeasts and yeast cell walls (T3; intact yeast), and 4) SE NAR challenge: basal diet with enzymatically-modified yeast products blend (T4; enzyme-modified yeast). The excreta samples were 100% positive for SE NAR at 3 days post-infection (dpi) in T2, T3, and T4. By 6 dpi, excreta samples were 87, 62 and 37% positive for T2, T3, and T4, respectively. Hens were euthanized at 7 dpi to harvest liver with gall bladder (L/GB), spleen, ovaries, and ceca. The recovery of SE NAR in L/GB was 75, 25 and 37% in T2, T3, and T4 (P < 0.05), whereas that of the spleen was 62, 25 and 37% in T2, T3 and T4 (P < 0.05), respectively. Treatments 3 and 4 reduced SE NAR counts (cfu/g) in the ceca from 4.3 log 10 to 2.7 and 1.95 log 10 , respectively, compared to T2 ( P < 0.05). The cecal count of SE NAR was 1.6 log 10 lower in T3 and 2.3 log 10 lower in T4 compared to T2. Both yeast derived products reduced Salmonella in internal organs and the ceca of laying hens. Enzymatically-modified yeast (T4) was better than its intact counterpart (T3) in reducing Salmonella counts in the ceca.

Genetic Polymorphism of Avian Leukosis Virus Host Receptors in Korean Native Chickens and Establishment of Resistant Line

Avian leukosis virus (ALV) is a highly contagious retrovirus that causes tumors and has resulted in great economic loss worldwide owing to its high transmission rate. Various ALV viral subgroups exist, with infections occurring via specific host receptors. The susceptibility or resistance of avian species to the ALV-A and K subgroups is determined by the host receptor, the tumor virus locus A (<i>tva</i>) gene, while that to ALV-B depends on another host receptor, the tumor virus locus B (<i>tvb</i>) gene. The resistance alleles of <i>tva</i> and <i>tvb</i> have primarily been identified in China, but none have been detected in Korea. We analyzed the frequencies of <i>tva</i> and <i>tvb</i> genotypes in White Leghorn (WL), Korean Ogye (KO), and Korean native chicken (KNC) breeds and assessed the resistance to ALV subgroups. In WL, both <i>tva</i> and <i>tvb</i> had various genotypes, including susceptibility and resistance alleles, whereas in KO, <i>tva</i> and <i>tvb</i> resistance alleles were dominant. In KNC, <i>tva</i> susceptibility and resistance alleles were mixed, whereas <i>tvb</i> resistance alleles were dominant. In addition, we showed that there were differences in the splicing pattern of <i>tva</i> transcripts and the expression level of <i>tvb</i> transcripts within breeds. Finally, we confirmed that ALV resistance depended on KO and KNC genotypes by <i>in vitro</i> infection of chicken embryonic fibroblasts with ALV. These results highlight that some KO and KNC individuals are naturally resistant to ALV subgroups A, B, and K and will facilitate the preservation of economically superior traits through selective breeding.

Assessing the genomic diversity and relatedness in 10 Canadian heritage chicken lines using whole‐genome sequence data

In the past 50 years, there has been a steep increase in the demand for poultry products, met by increasing production along with genetic selection for improved growth, efficiency, health and reproduction. The selection tends to reduce the number and type of genetic resources contributing to the majority of production. The University of Alberta maintains 10 heritage chicken lines (Brown Leghorn (BL), Light Sussex (LS), New Hampshire (NH), Saskatchewan Barred Rock (SaskBR), Shaver Barred Rock (ShaverBR), Shaver Rhode Island Red (RIR), White Leghorn (WL) and three commercial crosses called Alberta Meat Control strains 1957 (AMC-1957), 1978 sire line (AMC-1978-20S) and 1978 dam line (AMC-1978-30D), that played a large role in the evolution of the poultry industry in Canada. Since these lines have not been subjected to the same intensive selection pressures as commercial counterparts, they may contain unique genetic variants lost in commercial lines. Thus, for conservation management of these lines, the first step is to assess their genetic diversity. 71 male samples from across 10 lines were analysed using whole-genome sequencing and patterns of genetic diversity and relatedness among these lines were explored. AMC-1978-30D showed the highest genetic diversity as reflected in observed and expected heterozygosity (0.327 and 0.250), percentage of polymorphic markers (~ 65%) and average recent inbreeding coefficient (-0.039), followed by AMC-1978-20S and AMC-1957. BL showed the lowest genetic diversity as reflected in observed and expected heterozygosity (0.130 and 0.116), percentage of polymorphic markers (~31%) and average recent inbreeding coefficient (0.577), followed by LS, WL and NH. Our findings highlight the need for special attention for the populations of BL, WL, LS and NH, with the largest levels of inbreeding. Our results can be used to develop a breeding strategy to optimize and conserve the genetic variation present in heritage lines.

Domestication effects on social information transfer in chickens

Red junglefowl (RJF), ancestor of all domesticated chickens, is a highly social, omnivorous bird species, presumably with a capacity for social information sharing. During domestication, birds have been selected to live in large, dynamic groups, and this may have affected their social cognition. Here, we studied social information transfer in female RJF and domesticated White Leghorn (WL) chickens. Individuals were trained to open a puzzle-box feeder by pecking a lid and we then recorded the behaviour towards the same puzzle-box feeder for birds that had either observed the trained individual (“guided”) or saw the puzzle-box feeder for the first time (“naïve”). WL were considerably faster in approaching the feeder regardless of prior demonstration and pecked more at it. Both breeds were significantly faster to approach the puzzle-box feeder and pecked more after prior demonstration, but the effects were significantly stronger in WL. We conclude that both RJF and WL can utilize social information to address a novel problem, but during domestication this ability appears to have increased. The effects can be an effect of either social learning or stimulus enhancement. Some caution in this conclusion is necessary since we tested relatively few WL. Furthermore, possible confounding explanations include higher fearfulness in RJF and different effects of dominance interactions between demonstrators and observers.

Does Cell Proliferation Affect Embryonic Flexure and Torsion?

Two vital and simultaneous morphogenetic events that occur during early embryo development are the flexure and torsion (F&amp;T) of the embryonic body axis. Both contribute to development of the fetal position, which can be observed in avian and mammalian embryos. Correct progression of F&amp;T is crucial for the proper development of the heart and other organs. Embryonic flexure can be divided into three segments: cranial, cervical, and thoracic. In this study, we focus on cervical flexure and torsion of the embryonic body axis. Differential cell proliferation, the difference in the rate of division of cells between regions in the developing embryo, is one mechanism that could influence F&amp;T. Goodrum &amp; Jacobson (1981) observed thickening of the dorsal midbrain relative to the ventral midbrain during cranial flexure. Miller &amp; White (1998) have shown using mouse embryos that differential growth could cause torsion of an axis confined to an attached sphere.We performed studies inhibiting cell proliferation. Fertile white leghorn chick eggs were incubated to approximately Hamburger and Hamilton (HH) Stage 12 or 13. At these stages, F&amp;T have just begun. We then added aphidicolin, a mitotic inhibitor, to whole embryo culture. Embryos were observed at 0, 5, and 10 hours to see if F&amp;T were repressed. We hypothesized that the addition of aphidicolin would inhibit progression of F&amp;T. We developed quantitative schemes to score the extent of F&amp;T progression from HH 12 to HH 15. Embryos were scored from 0 to 4 based on the degree of cervical flexure and were also scored from 0 to 4 based on the degree of torsion. Afterward, the difference in F&amp;T scores of same embryos at time t=0 h and t=10 h was calculated to determine the extent of both. These scores were then averaged for multiple embryos.Compared with controls (n=46), embryos incubated in 400 µM aphidicolin (n=18) flexed and rotated at a significantly lower rate. For flexion, the mean difference in scores for control and treated embryos were 1.85 and 1.22, respectively. For torsion, the mean difference in scores for control and treated embryos were 1.62 and 1.25, respectively. These differences were statistically significant. It is noted that global application of aphidicolin did impact the overall health of embryos. However, our preliminary results indicate that differential cell proliferation could play a role in rotation and flexure progression in the developing chicken embryo.

Do the differences in egg contamination, penetration, and resistance against microorganisms among the hen genotypes exist?

Abstract The aim of this study was to evaluate and compare the impact of genotype and storage conditions (temperature and time) on microbiological contamination and eggshell quality. There were four genotypes of laying hens used, Czech Golden Spotted (CGS), Greenleg Partridge (GP), White Leghorn (WL) and commercial hybrid (CH) hens were included. After collection, the eggs were divided equally into five groups according to the storage time (0, 14, 28 days) and temperature (5 and 20°C). The microbiological analysis included counting of colonies forming units (CFU) of Escherichia coli (EC), Enterococcus (ENT) and total number of microorganisms (TNM) on eggshell surface, eggshell membranes and in thin albumen. The analysis of eggshell quality included the determination of eggshell proportion (SP), thickness (ST), strength (SST), index (SI) and surface (SS). Moreover, egg weight (EW) and egg weight loss (EWL) were determined. The significant effect of genotype was found in contamination of eggshell by EC, ENT and TNM, eggshell membranes by TNM and albumen by EC (all P≤0.05). The significantly lowest contamination of eggshell from EC was in eggs from the WL hens (4.42 log CFU/eggshell), while from ENT was in eggs from the CGS hens (1.22 log CFU/eggshell) and from the WL hens (1.40 log CFU/eggshell). The lowest incidence of TNM was also detected in eggs from the WL hens (5.03 log CFU/eggshell). Statistically the lowest contamination of eggshell membranes by TNM was found in eggs from the WL (0.12 log CFU/eggshell membranes) and CH hens (0.15 log CFU/eggshell membranes). Regarding the effect of genotype, the GP (not detected) and WL (not detected) hens had eggs with statistically the lowest occurrence of EC bacteria in albumen. Regarding the EW and eggshell quality, all the parameters were significantly affected by the genotype (P≤0.0001). Also EWL was significantly (P≤0.05) affected by genotype (after 14, 21 and 28 days of storage). There were found to be significant differences of microbial contamination of egg surface among observed hen genotypes. The penetration of selected microorganisms was also significant in contamination of eggshell membranes by TNM and in contamination of albumen by EC.

Genetic Parameter Estimation and Whole Sequencing Analysis of the Genetic Architecture of Chicken Keel Bending.

Bone health is particularly important for high-yielding commercial layer chickens. The keel of poultry is an extension of the abdomen side of the sternum along the sagittal plane and is one of the most important bones. In this study, the keel phenotype of White Leghorns laying hen flocks showed significant individual differences. To clarify its genetic mechanism, we first estimated the heritability of keel bend (KB) in White Leghorn, recorded the production performance of the chicken flock, examined the blood biochemical indexes and bone quality in KB and keel normal (KN) chickens, and performed whole-genome pooled sequencing in KB and KN chickens. We then performed selection elimination analysis to determine the genomic regions that may affect the keel phenotypes. The results show that KB is a medium heritability trait. We found that cage height had a significant effect on the KB (p < 0.01). At 48 weeks, there were significant differences in the number of eggs, the number of normal eggs, and eggshell strength (p < 0.05). The content of parathyroid hormone was lower (p < 0.01) and that of calcitonin was higher (p < 0.01) in KB chickens than in KN chickens. The differences in bone mineral density, bone strength, and bone cortical thickness of the humerus and femur were extremely significant (p < 0.01), with all being lower in KB chickens than in KN chickens. In addition, the bones of KB chickens contained more fat organization. A total of 128 genes were identified in selective sweep regions. We identified 10 important candidate genes: ACP5, WNT1, NFIX, CNN1, CALR, FKBP11, TRAPPC5, MAP2K7, RELA, and ENSGALG00000047166. Among the significantly enriched Kyoto Encyclopedia of Genes and Genomes pathways found, we identifed two bone-related pathways, one involving “osteoclast differentiation” and the other the “MAPK signaling pathway.” These results may help us better understand the molecular mechanism of bone traits in chickens and other birds and provide new insights for the genetic breeding of chickens.

Divergent selection for natural antibodies in poultry in the presence of a major gene

BackgroundNatural antibodies (NAb) are antibodies that are present in a healthy individual without requiring previous exposure to an exogenous antigen. Selection for high NAb levels might contribute to improved general disease resistance. Our aim was to analyse the genetic background of NAb based on a divergent selection experiment in poultry, and in particular the effect of a polymorphism in the TLR1A gene.MethodsThe study population consisted of a base population from a commercial pure-bred elite white leghorn layer line and seven generations of birds from a High and Low selection line. Birds were selected for total KLH-binding NAb titer (IgTotal). An enzyme-linked immunosorbent assay was performed to determine NAb titers in blood plasma for IgTotal and the antibody isotypes IgM and IgG. NAb titers were available for 10,878 birds. Genotypes for a polymorphism in TLR1A were determined for chickens in generations 5, 6 and 7. The data were analysed using mixed linear animal models.ResultsThe heritability estimate for IgM was 0.30 and higher than that for IgG and IgTotal (0.12). Maternal environmental effects explained 2 to 3% of the phenotypic variation in NAb. Selection for IgTotal resulted in a genetic difference between the High and Low line of 2.4 titer points (5.1 genetic standard deviation) in generation 7. For IgM, the selection response was asymmetrical and higher in the Low than the High line. The frequency of the TLR1A C allele was 0.45 in the base population and 0.66 and 0.04 in generation 7 of the High and Low line, respectively. The TLR1A polymorphism had large and significant effects on IgTotal and IgM. Estimated genotypic effects suggest full dominance of the TLR1A C allele. Significant TLR1A by generation interactions were detected for IgM and IgTotal.ConclusionsThe effect of a polymorphism in the TLR1A gene on IgTotal and IgM NAb was confirmed. Furthermore, we provide experimental verification of changes in allele frequencies at a major gene with dominant gene action on a quantitative trait that is subjected to mass selection. TLR1A by generation interactions indicate sensitivity to environmental factors.

Distribution of Infectious Bronchitis Virus Resistance in a Naïve Chicken Population.

Resistance to infectious bronchitis (IB) is a polygenic trait, but little is known about how resistance distributes in the host population. In this study, a relatively large number (n = 369) of specific-pathogen-free white leghorn chickens (Gallus gallus) were challenged with an Arkansas -type virulent IB virus (IBV), and resistance was evaluated 5 days after challenge by viral load (IBV RNA) in the trachea and cecal tonsils, as well as by tracheal histomorphometry (mucosal thickness and lymphocyte infiltration). Contrary to expectations, results showed a non-Gaussian distribution of resistance of the whole population against challenge. Indeed, most chickens accumulated toward higher resistance, i.e., lower viral loads and less tracheal damage. The current results also indicated limited differences in resistance to IBV between sexes. Tracheal viral load was significantly higher in males than that in females, but tracheal damage did not significantly differ between sexes. The difference in tracheal viral load found in males and females could have implications for viral spread in commercial chicken populations.

Electron-Beam Inactivation of Human Rotavirus (HRV) for the Production of Neutralizing Egg Yolk Antibodies

Electron beam (eBeam) inactivation of pathogens is a commercially proven technology in multiple industries. While commonly used in a variety of decontamination processes, this technology can be considered relatively new to the pharmaceutical industry. Rotavirus is the leading cause of severe gastroenteritis among infants, children, and at-risk adults. Infections are more severe in developing countries where access to health care, clean food, and water is limited. Passive immunization using orally administered egg yolk antibodies (chicken IgY) is proven for prophylaxis and therapy of viral diarrhea, owing to the stability of avian IgY in the harsh gut environment. Since preservation of viral antigenicity is critical for successful antibody production, the aim of this study was to demonstrate the effective use of electron beam irradiation as a method of pathogen inactivation to produce rotavirus-specific neutralizing egg yolk antibodies. White leghorn hens were immunized with the eBeam-inactivated viruses every 2 weeks until serum antibody titers peaked. The relative antigenicity of eBeam-inactivated Wa G1P[8] human rotavirus (HRV) was compared to live virus, thermally, and chemically inactivated virus preparations. Using a sandwich ELISA (with antibodies against recombinant VP8 for capture and detection of HRV), the live virus was as expected, most immunoreactive. The eBeam-inactivated HRV’s antigenicity was better preserved when compared to thermally and chemically inactivated viruses. Additionally, both egg yolk antibodies and serum-derived IgY were effective at neutralizing HRV in vitro. Electron beam inactivation is a suitable method for the inactivation of HRV and other enteric viruses for use in both passive and active immunization strategies.

Pathological effects of graded doses of aflatoxin B1 on the development of the testes in juvenile white leghorn males.

Current experiment was planned to investigate the deleterious effects of the graded doses of aflatoxin B1 (AFB1) on white leghorn male birds. For this purpose, one-hundred birds of 8weeks of age were divided into 4 equal groups and reared on feed contaminated with different doses of AFB1 for 10weeks. Group A was kept as a control group and was fed with normal toxin-free diet; groups B, C, and D were offered feed containing 100ppb, 200ppb, and 400ppb of AFB1, respectively. The birds were euthanized at the 4th and 10th week of the experiment. Clinical signs, behavioral changes, absolute and relative organ weight of the testes, and sperm motility were measured. Cellular immune response was observed through carbon clearance assay (CCA), P-HAP, and antibody response against sheep red blood cells (SRBC). Results showed a dose-dependent decline in the immune response of birds with the increase in the level of AFB1 in the feed. A significant decrease in the serum levels of testosterone, prolactin, and LH were observed at the end of the study. Grossly, testicular size and volume were reduced in ABF1 fed birds, while histological examination showed moderate to severe necrosis of testicular parenchyma, with partial to complete arrest of spermatogenesis. Very few spermatozoa were found in group C, while they were almost absent in group D which was offered a diet containing 400ppb AFB1. The motility of sperms was reduced in all treated groups except control. The abovementioned results showed that AFB1 had severe toxic effects on the reproductive and immunological parameters of WLH male birds in a dose-dependent manner.

A Deletion Upstream of SOX10 Causes Light Yellow Plumage Colour in Chicken.

Chicken plumage colour is a complex trait controlled by many genes. Herein, through Rhode Island Red (RIR) and White Leghorn (WL) F1 cross populations, the segregation of plumage color was observed in females, showing white in males, and dark red (DR) and light yellow (LY) in females. The white has been found to be caused by dominant white alleles (I) and the DR phenotype is attributed to a sex-linked recessive silver allele (). LY is a derived feather colour phenotype and the genetic mechanism of this is unclear. In order to explore the genetic basis for LY, we randomly selected 40 DR and 39 LY chickens for paired-end sequencing. Through the use of association analysis, we found the LY phenotype is caused by a 7.6 kb non-coding deletion near the SOX10 gene. This mutation has been reported to be responsible for dark brown plumage in chicken, and subsequent diagnostic PCR tests showed that the length of the long-range non-coding deletion is 7.6 kb instead of 8.3 kb as previously reported.

Mathematical modeling for egg production and egg weight curves in a synthetic white leghorn

This study was conducted to evaluate 8 mathematical models, namely, Logistic (LM), Morgqan Mercer Flodin (MMF), Polynomial Fit (PF), Rational Function (RF), Sinusoidal Fit (SF), Quadratic fit (QF), Gompertz function (GF), and Modification Compartmental Model (MCM) fitted to weekly egg production and egg weight of synthetic White Leghorn (SWL) population 21 to 40 wk of age of 5 generations (2015-16 to 2019-20). The relevant data for the present investigation were collected from SWL population, maintained in the department of Animal Genetics and Breeding, LUVAS, Hisar (India). The efficiency or reliability of the models were obtained by various criteria of goodness of fit such as coefficients of determination (R2), Root Mean Square Error (RMSE), Akaike's Information Criterion (AIC), Bayesian Information Criterion (BIC), graphical analysis, and Chi-square test. The results indicated that RF, MCM, SF, and PF were best models for fitting weekly egg production curve due to higher values of R2 and low values of RMSE, AIC, and BIC as compare to remaining models. In case of weekly egg weight, the best values of goodness of fit criteria were showed by MMF model followed by MCM and LM model. The results indicated that these models could be conveniently used for fitting for weekly egg production and egg weight in synthetic white leghorn, respectively.

Turicibacter bilis sp. nov., a novel bacterium isolated from the chicken eggshell and swine ileum.

Three novel, anaerobic, Gram-positive bacteria were isolated from the eggshell of two separate white leghorn chicken flocks and the ileum of a healthy pig, and designated MMM721T, ISU324 and PIG517 respectively. Cells were pleomorphic and capable of forming long chains of rods or coccoid clusters. Phylogenetic analysis of the 16S rRNA gene sequences identified these strains to be within the genus Turicibacter , of which only one species, Turicibacter sanguinis , has been formally described. However, whole genome sequencing of novel isolates returned a digital DNA–DNA hybridization value of 22.5 % and average nucleotide identity (ANI) values of 76.4 % (ANIb) and 86.0 % (ANIm), indicating divergence between the type strain MMM721T and T. sanguinis , suggesting the strains represented a novel species. The major fatty acid methyl esters of strain MMM721T were C16 : 0, C18 : 1 ω7c and C18 : 0. The strains mainly produced the volatile fatty acid lactate, along with smaller amounts of acetate and butyrate. Together, these data indicate that MMM721T, along with ISU324 and PIG517, represent a novel species within the genus Turicibacter . We propose the name Turicibacter bilis sp. nov. for the species. The type strain is MMM721T (=ATCC TSD-238T=CCUG 74757T).

Inherited scleroderma in young white leghorn chickens

This datasheet on inherited scleroderma in young white leghorn chickens covers Identity, Hosts/Species Affected, Diagnosis.

Prediction of Egg weight from Egg quality characteristics by using Regression Analysis Methods in White leghorn chicken

Prediction of Egg weight from Egg quality characteristics by using Regression Analysis Methods in White leghorn chicken

Protective effects of Aloe vera powder supplementation on some quantitative and qualitative characteristics of egg, histopathological changes and serum biochemistry of laying hens fed by Aflatoxin B1.

In the recent years, the use of medicinal plants to reduce the effects of mycotoxins in foods and feeds has been considered. This study was conducted to investigate the effects of Aloe vera on performance, serum biochemical parameters and liver histopathology in laying hens fed on aflatoxin B1 (AFB1)-contaminated diet. Seventy-two White Leghorns (Hy-Line W-36) were randomly allocated to four treatments. 1) basal diet (control), 2) control plus 1.00 mg kg-1 AFB1, 3) control diet plus 1.00 mg kg-1 AFB1 + 100 ppm Aloe vera powder, and 4) control diet plus 1.00 mg kg-1 AFB1 + 300 ppm Aloe vera powder. Each treatment consisted of three replicates of 6 birds. Egg weight and Haugh units were not affected by AFB1. Egg production and eggshell thickness were lower for groups fed 1.00 mg kg-1 AFB1. Egg production, egg weight and eggshell thickness were improved by incorporation of Aleo vera in the AFB1 contaminated feed but were not significant. Chickens fed AFB1 had significantly lower aspartate aminotransferase (AST), alanine aminotransferase (ALT) and uric acid and higher cholesterol than other groups. Aloe vera powder improved levels of cholesterol, uric acid, AST, and ALT. AFB1 also caused histopathological changes in liver tissues, such as vacuolar degeneration, fatty infiltration, and necrosis. The addition of Aloe vera powder to the aflatoxin containing diet reduced the severity of lesions in liver. The data demonstrated the ability of Aloe vera to reduce the adverse effects of AFB1 exposure in laying hens.

Effect of supplementation of acid protease in diets containing different levels of crude protein on performance of white leghorn layers

Effect of supplementation of acid protease in diets containing different levels of crude protein on performance of white leghorn layers

Effect of different stocking densities and flock size on welfare and behavior of white leghorn layers in conventional California cages

Effect of different stocking densities and flock size on welfare and behavior of white leghorn layers in conventional California cages

Effect of dietary inclusion of ashwagandha root powder on production performance, hematological parameters and immune response of white leghorn hens

Effect of dietary inclusion of ashwagandha root powder on production performance, hematological parameters and immune response of white leghorn hens