Hens Of Different Ages Research Articles

Effect of Egg Washing and Hen Age on Cuticle Quality and Bacterial Adherence in Table Eggs

The cuticle covering the outer surface of an eggshell functions as both a physical and chemical barrier against invading microorganisms. Contamination of eggs by microbial pathogens progresses in four stages: bacterial attachment to the egg surface, penetration through the cuticle and eggshell, multiplication within the underlying membranes, and the final stage of contaminating the egg contents. Therefore, it is important to study bacterial count at the first point of contact, i.e., on the surface of the eggs. In this study, we have evaluated the impact of differences in cuticle quality (due to egg washing and hen age) on bacterial load. We compared bacterial adherence on the eggshell surface of white eggs which were either washed (graded) or unwashed (ungraded), collected from Lohmann laying hens of different ages: early (24–28 weeks), mid-lay (44–48 weeks), and late (66–70 weeks). We aimed to determine the impact of hen age and egg washing on differences in cuticle quality and bacterial adherence. Our results indicate that hen age (up to 70 weeks) and commercial egg washing do not significantly impact bacterial adherence on eggshell surfaces. We have developed a novel method using green fluorescent protein (GFP)-expressing Salmonella typhimurium to estimate adherence of bacteria to the eggshell surface, with independent measurement of autofluorescence to quantitate cuticle deposition. S. typhimurium were localized, adhering to cracks visible on the outer cuticle in ungraded eggs, indicating that egg-associated pathogens usually enter the egg interior either through respiratory pores in eggshells or through shell micro-cracks. The results of this study can be utilized to optimize innovative methods for predictive microbiology in order to achieve egg safety.

Tracking perching behavior of cage-free laying hens with deep learning technologies

Providing perches in cage-free (CF) housing offers significant benefits for laying hens, such as improved leg muscle development, bone health, reduced abdominal fat, and decreased fear and aggression. A precise detection method is essential to ensure that hens engage in perching behavior from an early age, as manual observation is often labor-intensive and sometimes inaccurate. The objectives of this study were to (1) develop and test a deep learning model for detecting perching behavior; and (2) evaluate the optimal model's performance on detecting perching behavior of laying hens of different ages. In this study, recent deep learning models, that is, YOLOv8s-PB, YOLOv8x-PB, YOLOv7-PB, and YOLOv7x-PB, were developed, trained and compared in detecting perching behavior in 4 CF rooms (200 hens/room). Perch height was up to 1.8 m from the litter floor and situated 1.5 m below the cameras. A total of 3,000 images were used, with each image featuring at least 1 hen perching. The models' detection accuracies and their performance across different age groups of hens were compared using 1-way ANOVA at a 5% significance level. The results showed that the YOLOv8x-PB model outperform all other models used, achieving the precision of 94.80%, recall of 95.10%, and mean average precision (mAP@0.50) of 97.60%. While all models proved over 94% detection precision. With optimal model, PB detection precision was highest (97.40%) for peaking phase followed by prelay (95.20%), grower (94.80%), developer (94.70%) and layers (92.70%) phases while the lowest detection precision (88.80%) was for starter phase. Detection performance was somewhat reduced by the overlapping of birds during perching and occlusion. Overall, the YOLOv8x-PB model was the most optimal in detecting perching behavior, proposing a valuable tool for CF producers to monitor the perching activities of laying hens automatically.

Efficiency of ultraviolet light for disinfection of fertile broiler eggs

ABSTRACT This study aimed to evaluate the effectiveness of ultraviolet light in reducing bacterial load of eggshells and the impact of experimental disinfection on hatching, embryo mortality, and time-borne distribution using broiler breeder hens of different ages (38, 42, and 48 weeks old). Fertile eggs were subjected to different exposure periods (5, 7, and 9 minutes) of UV light (UV-C) with a 254 nm wavelength. For controls, eggs disinfected with paraformaldehyde (5.3 g/m3) and eggs not disinfected (NC). After subjection to disinfection protocols, the eggs were placed into sterile plastic bags containing 20 mL of peptone saline solution (0.1% m:v) and massaged for 1 minute to release the bacterial load. Aliquots of this solution were incubated in specific medium for bacterial growth for 48 hours at 37ºC for subsequent CFU counts. To evaluate the effects of disinfection on production, eggs previously disinfected by UV-C (9 min) and paraformaldehyde and NC eggs were candled between incubation days 10 and 13 and at the end of the incubation period to assess embryonic mortality. Hatchability distribution was performed every 8 hours. The 9 minutes 254nm UV-C light exposure was able to disinfect viable eggs and matched the effectiveness of the paraformaldehyde technique.

Dynamic Changes in Lung Microbiota of Broilers in Response to Aging and Ammonia Stress.

Comprehensive microbial analysis has revealed that the lung harbors a complex variety of microbiota, and although the dynamic distribution of the lung microbiota in mice and laying hens of different ages is well established, this distribution has not been clarified in broilers of different ages. Here, we performed 16S rRNA gene sequencing of lung lavage fluid from broilers at 3 (3D), 7 (7D), 14 (14D), 21 (21D), and 35 (35D) days of age to evaluate changes in the composition of their lung microbiota. Upon examination of the composition and function of the broiler lung microbiota, we found that their maturation increased significantly with age. Specifically, the microbiota composition was similar between 7 and 14D and between 21 and 35D. The relative abundance of aerobic bacteria in the broiler lungs gradually increased as the broilers developed, whereas the relative abundance of potentially pathogenic bacteria reached its highest level at 3D. The relative abundance of predicted functions in microbiota was very similar among 3, 7, and 14D, whereas the Glycan Biosynthesis and Metabolism pathway in microbiota was enriched at 21D. These findings suggest that these metabolic pathways play critical roles in shaping broiler microbiota at these age stages. In addition, short-term external ammonia stimulation significantly increased lung inflammation but did not significantly affect the lung microbiota. Taken together, these data reveal the dynamics of age-related changes in the microbiota of broiler lungs and the stability (the significant variation in the microbial composition) of these microbial communities in response to short-term ammonia stress. These findings provide new insights into the development of broiler lung microbiota and serve as a reference for subsequent studies to evaluate disease prevention in broilers subjected to large-scale breeding.

Effect of Laying Hen Genotype, Age and Some Interior Egg Quality Traits on Lysozyme Content

Abstract The objective of the study was to evaluate the quality of eggs laid by native breed hens of different ages (33 and 53 weeks of age), with particular consideration of the lysozyme parameters. Eggs were collected from 6 breeds/strains of laying hens under the genetic resources conservation in Poland, i.e. Greenleg Partridge (Z-11), Yellowleg Partridge (Ż-33), Rhode Island Red (R-11), Rhode Island White (A-33), Sussex (S-66) and Leghorn (H-22). The yolks of eggs from older hens had a more favourable, intense colour, but the freshness parameters (albumen height and Haugh units) of these eggs were lower. The albumen of eggs from older hens showed greater content and higher enzymatic activity of lysozyme in both thin and thick albumen. Among the six strains of hens, lysozyme content and enzymatic activity were highest in the egg albumen of strains Ż-33, Z-11 and R-11, and lowest in that of strain H-22. The analysed eggs showed statistically significant correlations between some interior egg quality traits (albumen weight, albumen height, Haugh units, yolk colour) and the discussed enzyme parameters. These traits are influenced by genotype and age of the hens.

Effect of age on the secretory activity of different layers of preovulatory follicles in laying hens

Age-related deterioration in female fertility is mainly associated with a decrease in the number and quality of ovarian follicles, which, in turn, leads to various endocrine disorders. In the present work, the steroidogenic activity of theca and granulosa layers from preovulatory follicles of laying hens of different ages was studied in vitro. Young hens aged 32-33 weeks with a long egg clutch and hens aged 74-76 weeks with a short egg clutch were used in the experiments. The granulosa and theca layers were isolated from the two largest preovulatory follicles F1 and F2 and cultured separately for 18 h. After culture, the concentration of sex steroid hormones in the media was determined by ELISA. The production of progesterone by the granulosa layer was 1.5-2.0 times higher in reproductively aged layers than in young layers. Concurrently, the secretory activity of granulosa cells increased with the development of follicles from the F2 stage to the F1 stage only in aged birds (from 74.0±7.5 to 97.0±10.9 pmol/mg tissue, P<0.05). Furthermore, testosterone production by the theca layer in aged hens was 2.0-2.8 times higher than that in young hens, but did not change significantly with the growth of follicles in birds of both groups. At the same time the ability of theca cells to secrete estradiol-17β was 1.6-2.3 times lower (P<0.001) in F1 than in F2 follicles, regardless of the age of the birds. The findings indicate that the processes associated with ovarian aging modulate the steroidogenic activity of follicular cells in laying hens, with the age-related reduction in the egg clutch being related to an increase in the basal production of progesterone and testosterone in the two largest preovulatory follicles.

Age and Calcium Sources in Laying Hen Feed Affect Calcium Digestibility

The apparent calcium (Ca) digestibility coefficient (ADC) and true digestibility coefficient (TDC) of different inorganic calcium sources were determined in laying hens of different ages. Three Ca digestibility tests were carried out, each assessing 240 Lohmann Brown lineage laying hens distributed in a completely randomized design. Nine dietary treatments were arranged in a 3 × 3 factorial design consisting of three ages (40, 50 and 70 weeks) × three Ca (dicalcium phosphate (DCP) sources, fine (FL) and coarse (CL)) limestone, comprising eight replicates per treatment of six birds per experimental unit. Regarding the DCP, the ADC was higher (P as 0.889, 0.613 and 0.712, respectively. No effect (P > 0.05) of age on the ADC was noted for either FL or CL. Comparing Ca sources, DCP exhibited a higher (P 0.05). Endogenous loss values of 790, 860 and 930 mg·kg-1 of consumed dry matter were observed at 40, 50 and 70 weeks, respectively. For the TDC, no interaction (P > 0.05) was observed between Ca sources and bird age. The highest TDC value (P > 0.05) was found in birds fed DCP (0.786) followed by FL (0.637) and CL (0.534). In addition, birds at 40 weeks of age (0.714) exhibited higher TDC values (P

Shelf life of brown eggs from laying hens of different ages in organic production system / Vida de prateleira de ovos marrons de poedeiras com diferentes idades de postura em sistema orgânico de produção

The aim of this study was to evaluate the shelf life of brown eggs from laying hens of different ages in an organic production system. A total of 192 brown eggs from laying hens were used, t experimental design was in a factorial scheme, with four laying hens ages (40, 50, 60, 70, weeks) and four storage periods (0, 14, 28 and 42 days) with 12 repetitions each. Chicken age and storage period (p <0.05) interfered with egg weight loss. Eggs from older laying hens showed superior internal quality in the first days of storage, but with high susceptibility to losses when stored for up to 42 days. Young laying hens (up to 40 weeks of age) showed better internal egg quality when compared to chickens with 50 and 60 weeks of age, when stored for up to 42 days. The albumen pH was not affected by the age of the laying hens, but increased significantly with a longer storage period. The shelf life of the eggs was affected by the age of the laying hens and the storage time.

Age-related changes in egg yolk composition between conventional and organic table eggs

The aim of this study was to investigate fatty acids, fat-soluble vitamins, malondialdehyde and cholesterol in conventional and organic eggs obtained from hens of different ages (30 and 60 weeks). A total of 360 egg yolks were used in this study. Polyunsaturated fatty acid, omega-3, and omega-6 levels were higher in the organic eggs from the 30-week-old hens. The monounsaturated fatty acid level was higher in the conventional eggs but was the same between the two age groups. Cholesterol and vitamin A levels were not influenced by either the rearing system or the age of the hens. The malondialdehyde, vitamin D2, and vitamin K2 were higher in the organic eggs; however, vitamin E was higher in the conventional eggs. The results showed that the rearing system and age, as well as the diet, had an impact on the composition of the egg. Total levels of polyunsaturated fatty acid, omega-3, and omega-6 are higher in organic eggs produced by younger hens.

Особливості годівлі курей-несучок за органічного вирощування

The consumption of organic products in Ukraine is gradually growing. Consumer awareness of the general rules for compulsory certification increases the credibility of manufacturers and the demand for such products. The article provides an analytical review of the current state of the problem of feeding organic poultry, in particular the replacement of synthetic amino acids in feed with natural components, a list of means for the prevention of gastrointestinal diseases of poultry by organic farming is given. The results of the study of feed mixtures and their components are presented. The studies were carried out in two organic poultry farms in Ukraine, as well as in accredited laboratories of veterinary medicine. Physicochemical, microbiological and chemical-toxicological research methods were used. According to the research results, rations for laying hens of different ages were developed and balanced in terms of nutritional value, energy value and other indicators. The article also describes the effect of dysbiosis on the health of poultry and the importance of intestinal probiotic flora in the correction of eubiosis. The use of natural preventive substances in poultry feeding, in particular of microbiological origin and phyto- and bioregulation preparations, is proposed. The basic principles of improving the quantitative and qualitative composition of the poultry intestinal microflora with the help of safe and ecological therapeutic and prophylactic drugs are formulated.

Fatty liver haemorrhagic syndrome occurrence in laying hens: impact of production system

ABSTRACTSurveys were conducted with cage and alternative layer production systems to assess the prevalence of fatty liver haemorrhagic syndrome (FLHS). Commercial caged laying hens of different ages from three farms in Queensland were monitored for three months. The mortality rate of flocks ranged from 0.8% (the youngest flock) to 11.6% (the oldest flock). Six hundred and fifty-one birds were necropsied, and approximately 40% of hens died due to FLHS. Hens kept in cages in a controlled environment shed, were at a similar risk of developing FLHS to hens kept in naturally controlled sheds, however, the heavier birds in a flock were more likely to have the condition than lighter birds. In another study, layer flocks kept in cage, barn and free-range housing systems at the University of Queensland facility, were monitored for 50 weeks. Data from necropsies and performance records showed no significant differences in mortality rates between the housing systems (6.1%, 6.4% and 5.8%, for cages, barns and free-range, respectively), but the cause of mortality was different. In cages, 74% of necropsied hens died due to FLHS. In the other systems, only 0–5% of dead hens were diagnosed with the condition. These results are in agreement with previous Australian and overseas findings which have shown that FLHS is one of the main causes of hen death in caged flocks. Factors associated with husbandry practices in different production systems, such as restricted movement, increased production and temperature variations, influence hepatic lipid metabolism and predispose hens to FLHS.

Age-Dependent Variation of Telomere Length and DNA Damage in Chicken

Birds are unique models for molecular studies on aging processes and cellular senescence because of their slow rates of aging and comparatively long life spans among homoeothermic animals. The study aimed to examine the relative telomere length and amount of nuclear, mitochondrial DNA lesions in hens of different ages and to find out the correlation between these biomarkers of aging. The study was carried out on hens of crossbreed «High Sex Brown» of different age groups - 1, 75, 225, 330, 450 days old. The measurements of telomeres and DNA damage were done in red cells of hens using quantitative PCR technique. We found out that the amount of telomeric DNA reduced significantly with age. Telomere length ratio to control group (1 day old) made up: 0.88±0.08 for 75 days old, 0.73±0.07 for 225 days old, 0.66±0.1 for 330-days old and 0.58±0.12 for 450 days old. The amount of DNA lesions in both genomes had great, age-dependent increase. The relative quantity of lesions per 10 kb detected in the nuclear DNA were as follows: 0.17±0.19 for 75 days old, 0.66±0.21 for 225 days old, 1.02±0.33 for 330-days old and 1.48±0.45 for 450 days old and the relative quantity of lesions in mtDNA were as follows: 0.11±0.06 for 75 days old, 0.84±0.23 for 225 days old, 1.18±0.3 for 330-days old and 1.49±0.35 for 450 days old. The results obtained are of fundamental interest for aging processes, as well as could have an economic value for poultry farming.

Transient and Prolonged Response of Chicken Cecum Mucosa to Colonization with Different Gut Microbiota

In this study we determined protein and gene expression in the caeca of newly hatched chickens inoculated with cecal contents sourced from hens of different ages. Over 250 proteins exhibited modified expression levels in response to microbiota inoculation. The most significant inductions were observed for ISG12-2, OASL, ES1, LYG2, DMBT1-L, CDD, ANGPTL6, B2M, CUZD1, IgM and Ig lambda chain. Of these, ISG12-2, ES1 and both immunoglobulins were expressed at lower levels in germ-free chickens compared to conventional chickens. In contrast, CELA2A, BRT-2, ALDH1A1, ADH1C, AKR1B1L, HEXB, ALDH2, ALDOB, CALB1 and TTR were expressed at lower levels following inoculation of microbiota. When chicks were given microbiota preparations from different age donors, the recipients mounted differential responses to the inoculation which also differed from the response profile in naturally colonised birds. For example, B2M, CUZD1 and CELA2A responded differently to the inoculation with microbiota of 4- or 40-week-old hens. The increased or decreased gene expression could be recorded 6 weeks after the inoculation of newly hatched chickens. To characterise the proteins that may directly interact with the microbiota we characterised chicken proteins that co-purified with the microbiota and identified a range of host proteins including CDD, ANGPTL6, DMBT1-L, MEP1A and Ig lambda. We propose that induction of ISG12-2 results in reduced apoptosis of host cells exposed to the colonizing commensal microbiota and that CDD, ANGPTL6, DMBT1-L, MEP1A and Ig lambda reduce contact of luminal microbiota with the gut epithelium thereby reducing the inflammatory response.

Risk Factors Associated With Salmonella in Laying Hen Farms: Systematic Review of Observational Studies.

Salmonella contamination of laying hen flocks and shell eggs is associated with various management and environmental factors. Foodborne outbreaks of human salmonellosis have been traced back to consumption of Salmonella-contaminated shell eggs. In the present study, a systematic literature review was conducted to identify and provide an evidence-based overview of potential risk factors of Salmonella contamination of laying hens, layer premises, and shell eggs. This systematic literature search was conducted using AGRICOLA, CAB Abstracts, and PubMed databases. Observational studies that identified risk factors for Salmonella contamination of layer flocks and shell eggs were selected, and best evidence was synthesized to summarize the results. Altogether, 13 cross-sectional studies and four longitudinal studies published in English were included in the review. Evidence scores were assigned based on the study design and quality of the study to grade the evidence level. The strength of association of a risk factor was determined according to the odds ratios. In this systematic review, the presence of previous Salmonella infection, absence of cleaning and disinfection, presence of rodents, induced molting, larger flock size (>30,000 hens), multiage management, cage housing systems, in-line egg processing, rearing pullets on the floor, pests with access to feed prior to movement to the feed trough, visitors allowed in the layer houses, and trucks near farms and air inlets were identified as the risk factors associated with Salmonella contamination of laying hen premises, whereas high level of manure contamination, middle and late phase of production, high degree of egg-handling equipment contamination, flock size of >30,000, and egg production rate of >96% were identified as the risk factors associated with Salmonella contamination of shell eggs. These risk factors demonstrated strong to moderate evidence of association with Salmonella contamination of laying hens and shell eggs. Eggshells testing positive for Salmonella were 59 times higher when fecal samples were positive and nine times higher when floor dust samples were positive. Risk factors associated with Salmonella Enteritidis infection in laying hens were flock size, housing system, and farms with hens of different ages. As a summary, this systematic review demonstrated that Salmonella contamination of laying hen flocks and shell eggs in layer production systems is multifactorial. This study provides a knowledge base for the implementation of targeted intervention strategies to control Salmonella contamination of laying hen flocks and shell eggs.

Bioactive amines and internal quality of commercial eggs

The physicochemical and microbiological qualities of commercial eggs produced by layer hens of different ages (approximately 30 and 60 wk old) were submitted to storage under room temperature or refrigeration for 28 d. A total of 600 eggs were subjected to microbiological analyses of their inner contents and another 600 to a determination of Haugh units (HU) and bioactive amine content. A decrease in the quality of the inner contents of the eggs was observed during the experiment, mainly in the eggs from the 60-wk-old layers, which presented the worst HU values when stored at room temperature (P < 0.05). Microbiological analyses showed an absence of Salmonella spp., Staphylococcus aureus, and coliforms, either total or thermal-tolerant; however, low counts of other Staphylococcus species, Enterobacter spp., Pseudomonas spp., mesophilic aerobic bacteria, and fungi were also recorded. The chromatographic analysis of bioactive amines detected the presence of phenylethylamine in all albumens (38.0 mg/kg) and spermidine in the yolks (1.02 mg/kg). It was concluded that the age of the hens and the time and temperature of storage influenced the quality parameters of the eggs (P < 0.05). Furthermore, despite the low levels of microbial contamination found, phenylethylamine was detected in the albumen. It was not possible to establish index of quality of eggs using bioactive amines present in the yolk and albumen of eggs.

Qualidade de ovos comerciais submetidos a diferentes condições de armazenamento

Verificou-se a qualidade interna de 1440 ovos de consumo, provenientes de galinhas de linhagem comercial. O delineamento foi inteiramente ao acaso, em arranjo fatorial 2x2x15, com duas diferentes idades das galinhas (33 e 60 semanas), duas condições de armazenamento (ambiente e refrigerado) e 15 períodos de estocagem (um, dois, três, quatro, cinco, seis, sete, oito, nove, 10, 11, 12, 13, 14 e 15 dias). Os parâmetros de qualidade dos ovos avaliados foram Unidades Haugh (UH), pH do albúmen (pH), sólidos totais do albúmen (STA) e da gema (STG), e peso e porcentagem de albúmen, gema e casca. Foi observada diminuição da qualidade interna dos ovos durante o armazenamento. Os ovos produzidos por poedeiras velhas e armazenados em temperatura ambiente apresentaram os piores resultados de UH. O pH do albúmen aumentou no decorrer do armazenamento independentemente da idade da ave e da temperatura de estocagem, e os valores de STA aumentaram com o armazenamento em temperatura ambiente. Concluiu-se que a idade da ave, a temperatura e o tempo de armazenamento dos ovos exercem influência sobre os parâmetros de qualidade do ovo.

Comparative efficacy of a yeast product and bacitracin methylene disalicylate in enhancing early growth and intestinal maturation in broiler chicks from breeder hens of different ages

The intestine of the newly hatched chick is immature at hatch. Yeast contains nucleotides and β-glucans that enhance intestinal development and chick growth. Accordingly, a 14-d experiment was conducted to evaluate the efficacy of a novel yeast product and bacitracin methylene disalicylate in enhancing early growth and intestinal maturation in chicks obtained from young (26–27 wk old) and old (58 to 59 wk old) breeder hens. Chicks (384) were randomly assigned to 8 dietary treatments. Treatment 1 (YH) consisted of chicks, from young hens, fed corn-soybean meal (SBM) diet alone. Treatment 2 (YHB) consisted of chicks, from young hens, fed corn-SBM basal into which BMD was added at 0.055 g/kg. Treatment 3 (YHE) consisted of chicks, from young hens, fed corn-SBM basal into which yeast extract (YE) was added at 0.075% level. Treatment 4 (YHED) consisted of chicks, from young hens, fed corn-SBM basal into which YE was added at 0.15% level. Treatments 5 (OH), 6 (OHB), 7 (OHE), and 8 (OHED) consisted of chicks from old hens fed diets similar to those given to YH in treatments 1, 2, 3, and 4, respectively. Growth performance (body weight gain and feed conversion ratio) was evaluated on d 7 and 14. Intestinal tissue samples were also analyzed for alkaline phosphatase (ALP) activity as an indicator of intestinal maturation on d 4 and 13 of experiment. Results showed that by d 14 of experiment, only BMD treatments (YHB and OHB) improved body weight gain (P < 0.05). However, the body weight gains of chicks in the yeast-supplemented treatments (YHE, YHED, OHE, and OHED) were statistically similar (P > 0.05) to those of the BMD treatments. Ileal ALP activity was consistently enhanced by BMD and yeast product supplemented at 0.075% of the diet. It was concluded that antibiotic BMD and our novel yeast product supplemented at 0.075% of the diet improved early chick growth and maturation of the ileal segment of the small intestine.

Risk factors for Salmonella enterica subsp. enterica contamination in 519 French laying hen flocks at the end of the laying period

A cross-sectional study was carried out to identify risk factors for Salmonella spp. contamination in French laying hen flocks at the end of the laying period. Five hundred and nineteen flocks were studied between October 2004 and September 2005. The Salmonella status of the flocks was assessed from 5 faeces samples (pooled faeces samples from cage flocks and foot swabs from flocks kept on the floor, i.e. in a barn, outdoors and on organic farms) and 2 dust samples analysed using a classical bacteriological method. At least one contaminated sample was found in 93 flocks and the apparent prevalence of Salmonella was 17.9% (CI 95% = 14.5, 21.3). Prevalence was significantly higher in caged flocks than in on-floor flocks and logistic-regression models were built for each subpopulation. Associations between farm characteristics, managerial practices and the presence of one or more Salmonella-positive samples in a flock were assessed using a mixed logistic-regression model with a flock-specific random effect. In caged flocks ( n = 227) the risk of Salmonella contamination increased with flock size and when delivery trucks passed near poultry-house entrances. The risk of detecting a positive sample was lower with pooled faeces samples than with dust samples. In on-floor flocks ( n = 292), a higher risk of contamination was associated with multistage management (presence of hens of different ages on the farm) and contamination by Salmonella Enteritidis of a previous flock kept on the farm. However, the use of a container for dead bird disposal was a protective factor.

Additions of Killed Whole Cell Bacteria Preparations to Freund Complete Adjuvant Alter Laying Hen Antibody Response to Soluble Protein Antigen

Passive transfer of antibodies from hen to egg has value to both the producer of commercial polyclonal egg antibody and the producer of hatching eggs. Water-in-oil emulsions are commonly amended with immune stimulants such as Mycobacteria (e.g., Freund complete adjuvant; FCA) to increase antibody production to soluble protein antigens (SPA). Recent discoveries of the mechanisms by which microbial products act as adjuvants led us to hypothesize that additions of killed whole cell bacteria (bacterins) to FCA could improve antibody responses to SPA. All injections used in each experiment were water-in-oil emulsions (50:50) containing 3 mg/mL of phospholipase A(2) (PLA(2)) immunogen. Additionally, all primary control and treatment injections contained heat-killed Mycobacterium butyricum immunogens from FCA. In addition to PLA(2) and FCA, primary treatment injections contained various microbial bacterin immunogens. Hence, the experimental treatment of all experiments was addition of a commercial source of microbial bacterin to FCA for the primary injection only. Booster injections were the same as the primary control injections except Freund incomplete adjuvant replaced FCA. Anti-body titers to PLA(2) in yolk were determined by ELISA. Bacterins tested as additives to FCA were Escherichia coli, Staphylococcus aureus, Streptococcus suis, and Corynebacterium pseudotuberculosis. Escherichia coli bacterin added to FCA decreased egg yolk antibody titer to SPA by 23% in hens of different ages and strains (P < 0.0001). In a second experiment, a 51% decrease in antibody production associated with E. coli bacterin was sustained for several weeks after the primary immunization (P = 0.003). Staphylococcus aureus or Streptococcus suis combined with FCA increased egg yolk antibody 62 and 51%, respectively (P < 0.05), and Corynebacterium pseudotuberculosis had no effect. In conclusion, the addition of bacterin to FCA can influence hen antibody response to SPA as measured in egg yolks. It is hypothesized that the difference in antibody production may be related to the composition of various pathogen associated molecular patterns in the primary injection.

Expression of AGR-2 in Chicken Oviduct during Laying Period

The chicken oviduct is a dynamic organ that produces secretory proteins such as ovalbumin during the laying period. In this study, we identified oviduct-specific proteins in hens during the egg-laying period by proteomic analysis. Proteins extracted from the magnum of hens of different ages (5, 35, and 65 weeks) were analyzed by two-dimensional gel electrophoresis to compare the intensity of proteins among samples. Approximately 300 spots were detected on each gel. Based on the comparison of image gels, we found that the intensity of eight spots in 35-week magnums was increased at least by 2-fold compared with the others. Five of the eight spots were identified as calumenin, acidic ribosomal phosphoproteins (ARP), prohibitin, heart fatty acid-binding protein, and anterior gradient-2 (AGR-2). In particular, ARP and AGR-2 were highly expressed in 35- week magnums compared with 5- and 65-week magnums. In addition, the level of these proteins was consistent with their RNA levels. Expression of AGR-2 mRNA was detected in the mature magnum, whereas no signal was observed in premature tissue. Among various tissues, expression of AGR-2 mRNA was highest in the magnum, high in the isthmus, and five fold lower in muscle. It was undetectable in the liver and in other tissues (heart and kidney). However, the mRNA levels of other proteins were ubiquitous among tissues. In transcriptional activity of AGR-2, a 3.0 kb fragment of promoter region containing potential estrogen receptor binding sites had enhanced its activity strongly. In conclusion, these results suggest that AGR-2 has functional regulatory roles in the chicken oviduct during the egglaying period.