Serum IgY Research Articles

Effect of an artificial Ascaridia galli infection on egg production, immune response, and liver lipid reserve of free-range laying hens

This study was conducted to determine the effect of Ascaridia galli infection on free-range laying hens. Lohmann Brown laying hens (n = 200) at 17 wk of age were allocated to 4 treatment groups (n = 50 per group), each with 5 replicate pens of 10 hens. Hens in 3 treatment groups were orally inoculated with different doses of embryonated A. galli eggs: low (250 eggs), medium (1,000 eggs), and high (2,500 eggs) levels, whereas hens of the control group were not infected. Infection levels were monitored using excreta egg counts and mature A. galli worm counts in the intestine. Anti A. galli antibody titers (IgY) in the serum were measured prior to infection, and at 6, 11, 15, and 20 wk post infection (PI) and in egg yolk at 11 and 20 wk PI. Parameters evaluated included feed intake, egg production, egg weight, egg mass, FCR, liver weight, liver fat, and intra epithelial immune cell infiltration. The results showed no difference in feed intake, body weight, or FCR among any treatment groups (P > 0.05). Egg production was lower in the low infection group compared to other groups at 20 wk of age (P < 0.01). Serum IgY was higher in the infected groups’ hens at 20 wk PI compared to control group hens (P < 0.01). Yolk IgY increased significantly over time and was higher in infected hens compared to hens of the control group at 11 and 20 wk PI (P < 0.001). No differences were observed in liver lipid content or intraepithelial lymphocytes infiltration among treatment groups. Ascaridia galli eggs in the coprodeum content and adult A. galli worm count were higher in infected hens compared to hens of the control group (P < 0.01). In conclusion, the effects of artificial infection with A. galli on the parameters investigated were minor, and egg yolk antibody may be a more reliable indicator of A. galli infection than serum antibody or excreta egg count.

Comparative study on Pharmacokinetic Profiles of Chicken IgY to Horse IgG in Rabbits

Chicken IgY antibody has been extensively reported for various applications as an alternative to mammalian IgG. To evaluated the pharmacokinetics profile of chicken IgY in comparison with horse IgG. Chicken IgY antibody was prepared by immunizing the white leghorn chicken with tetanus toxoid (TT) and then extracted anti-TT-IgY from immune egg yolks by PEG-6000 extraction. The titer of anti-TT-IgY was determined by ELISA in order to select the hyper immune eggs for further extraction. Rabbits were injected with 300 μg/kg of Chicken IgY and horse IgG by intravenous (i.v.) and intramuscular (i.m.) administrations. Then, the concentrations of IgY and IgG in rabbit serum were determined using indirect ELISA. Pharmacokinetic parameters were estimated using non-compartmental analysis. IgY can reach higher concentration (Cmax= 4.54 mg/L after i.m. injection) within shorter time (Tmax= 0.12 h after i.m. injection) than IgG (Cmax= 3.99 ng/mL after i.m. injection; Tmax=0.11 h after i.m. injection), while the IgY lifespan (T1/2=26.98 h and 31.98 h after i.v. and i.m. administration, respectively) in the body was comparable with IgG (T1/2=27.94 h and 29.58 h after i.v. and i.m. administration, respectively). IgY might be a promising choice as an alternative to mammalian sourced antibodies.

Performa Produksi dan Reproduksi Ayam Sentul dengan Konsentrasi IgY Berbeda dalam Serum Darah

This study was aimed to evaluate the effect of different IgY concentrations on the production performance and quality of semen sentul cocks with different total IgY in serum. This research used 20 sentul cocks with 4 month age consisted of 10 cocks with high IgY concentration and 10 cocks with low IgY concentration. Variabels observed included production performance (feed consumption, weight gain of feed conversion, final body weight, mortality) and quality semen (macroscopic and microscopic). Study was designed using completely randomized design (RAL) with 2 treatments. All treatments were repeated 10 times. The results started that IgY concentrations treatment did not affect DMA production performance and quality of semen, but signicantly affecting (p&lt;0.05) mass movement of spermatozoa.

Humoral immune responses to select marine bacteria in loggerhead,Caretta caretta, and Kemp’s ridley,Lepidochelys kempii, sea turtles from the south eastern United States

Serum from Kemp's ridley and loggerhead sea turtles was collected in summers of 2011, 2012, and 2013. Serum IgY recognition of lysate proteins from nine bacteria species and whole bacteria-specific IgY titers to these pathogens were quantified. Serum and purified IgY recognized proteins of all bacteria, with protein recognition in some species more pronounced than others. Circulating IgY titers against V. vulnificus, V. anguillarum, E. rhusiopathiae, and B. vesicularis changed over the years in Kemp's ridley turtles, while titers IgY against V. vulnificus, E. coli, V. parahaemolyticus, B. vesicularis, and M. marinum were different in loggerhead turtles. Serum lysozyme activity was constant for loggerhead turtles over the 3years, while activity in Kemp's ridleys were lower in 2012 than 2013. Blood PCV, glucose levels, and serum protein levels were comparable to healthy turtles in previous studies, therefore, this study provides baseline information on antibody responses in healthy, wild turtles. Received 25 May 2017 accepted 09 Oct 2017 revised 15 Sep 2017.

Humoral and cytokine response elicited during immunisation with recombinant Immune Mapped protein-1 (EtIMP-1) and oocysts of Eimeria tenella

Eimeria tenella, the causative agent of caecal coccidiosis, is a pathogenic gut dwelling protozoan which can cause severe morbidity and mortality in farmed chickens. Immune mapped protein-1 (IMP-1) has been identified as an anticoccidial vaccine candidate; in the present study allelic polymorphism was assessed across the IMP-1 coding sequence in E. tenella isolates from four countries and compared with the UK reference Houghton strain. Nucleotide diversity was low, limited to expansion/contraction of a CAG triplet repeat and five substitutions, three of which were non-synonymous. The EtIMP-1 coding sequence from a cloned Indian E. tenella isolate was expressed in E. coli and purified as a His-tagged thioredoxin fusion protein. An in-vivo vaccination and challenge trial was conducted to test the vaccine potential of recombinant EtIMP-1 (rEtIMP-1) and to compare post-vaccination immune responses of chickens to those stimulated by live oocyst infection. Following challenge, parasite replication measured using quantitative PCR was significantly reduced in chickens that had been vaccinated with rEtIMP-1 (rIC group; 67% reduction compared to UC or unimmunised controls; 79% reduction compared to rTC group or recombinant thioredoxin mock-immunised controls, p<0.05), or the birds vaccinated by infection with oocysts (OC group, 90% compared to unimmunised controls). Chickens vaccinated with oocysts (OC) had significantly higher levels of interferon gamma in their serum post-challenge, compared to rEtIMP-1 vaccinated birds (rIC). Conversely rEtIMP-1 (rIC) vaccinated birds had significantly higher antigen specific serum IgY responses, correlating with higher serum IL-4 (both p<0.05).

Immunogenicity and protective efficacy of virus-like particles and recombinant fiber proteins in broiler-breeder vaccination against fowl adenovirus (FAdV)-8b

Inclusion body hepatitis (IBH) is an economically important diseases in broiler chicken industry. Several serotypes of fowl adenovirus (FAdV) can cause IBH, among them, serotype FAdV-8b is associated with the majority of the IBH cases in Canada. Here, we evaluated FAdV-8b virus-like particles (VLPs) and recombinant FAdV-8b fiber proteins (expressed in E. coli) as potential broiler-breeder vaccines against IBH. For assessing the immunogenicity of vaccines, we investigated both humoral and cellular immunity. The humoral immune response was evaluated by determining total IgY and virus-neutralizing antibody in serum at 14, 28, 35 and 60days post-immunization (dpi). We examined cellular immunity using flow cytometry by determining CD4:CD8 ratio change in peripheral blood after the booster vaccination. The protective effect of vaccines was tested by challenging 14day-old progeny (n=30/group) carrying maternal antibodies (MtAb) by challenging with virulent FAdV-8b virus (1×107 TCID50, FAdV-8b-SK). Although total IgY levels were comparable in all groups, the neutralizing antibody response in broiler-breeders at 35 and 60 dpi was significantly (p<0.05) higher those vaccinated with FAdV-8b VLPs followed by FAdV-8b fiber compared to fiber-knob. Moreover, vaccines comprised of FAdV-8b VLPs and FAdV-8b fiber rather than FAdV-8b fiber-knob efficiently elicited the cell-mediated immune response as evidenced by a statistically significant (p<0.05) CD8+ T-cell proliferative response in broiler-breeders four days after the booster vaccination. Unlike FAdV-8b fiber-knob, FAdV-8b VLPs, and FAdV-8b fiber vaccinated broiler-breeders were able to transfer a substantial amount (28.4±9%) of MtAb to their progeny. Challenge revealed that MtAb provided 100% and 82.7% protection in progeny hatched from FAdV-8b VLPs, and FAdV-8b fiber vaccinated broiler-breeders, respectively. Collectively, our data suggest that FAdV-8b subunit vaccine-induced MtAb efficiently protected progeny against clinical IBH and broiler-breeder vaccination with subunit vaccines is a potential approach to protect against IBH.

Immunological aspects of the efficiency of protectotype vaccination strategy against chicken infectious bronchitis.

BackgroundOne of the most commonly applied protectotype vaccination protocol against infectious bronchitis (IB) in broiler chickens in the EU is simultaneous or alternate use of Ma5 and 4/91 vaccine strains. After IB vaccination and infection, systemic and upper respiratory tract (URT), humoral and cell-mediated immunity (CMI), are stimulated. The level of this stimulation correlates with the level of protection against IB.ResultsWe’ve investigated the development of URT and systemic, cell-mediated and humoral immunity in commercial broiler chickens vaccinated with Ma5 and/or 4/91 strains at hatch day. We’ve demonstrated that the group vaccinated with Ma5 and 4/91 strain simultaneously developed the most desirable immunity which reflects the level of CD8+ T cells stimulation in spleen and Harderian gland, as well as the level of IgA and IgY in URT washings and serum and their cross-reactivity with 7 IBV strains.ConclusionsAlthough we did not demonstrate directly why Ma5 + 4/91 protocol is so efficient it seems that it combines the benefits of monovalent vaccination with either Ma5 or 4/91 and while Ma5 seems to stimulate CMI more efficiently, the 4/91 strain generates a wider spectrum of immune system cross-reactivity and higher URT IgA production.

Outer membrane vesicles of Gallibacterium anatis induce protective immunity in egg-laying hens

Gallibacterium anatis causes infections in the reproductive tract of egg-laying hens and induce increased mortality and decreased egg production. New prophylactic measures are needed in order to improve animal welfare and production efficiency. Bacterial outer membrane vesicles (OMVs) have previously shown promising results in protection against infections and we hypothesized that OMVs could serve as an immunogen to protect egg-laying hens against G. anatis. To investigate the immunogenic potential of G. anatis OMVs, two in vivo studies in egg-laying hens were made. The trials assessedthe degree of protection provided by immunization with G. anatis OMV against challenge and the IgY responses in serum after immunization and challenge, respectively. A total of 64 egg-laying hens were included in the trials. OMVs for immunization were produced and purified from a high-producing G. anatis ΔtolR mutant. Challenge was done with G. anatis 12656-12 and evaluated by scoring lesions and bacterial re-isolation rates from peritoneum. Finally, levels of OMV-specific IgY in sera were assayed by ELISA. Immunization with OMVs decreased the lesions scores significantly, while the bacterial re-isolation remained unchanged. Furthermore, a high OMV-specific IgY response was induced by immunization and subsequent challenge of the hens. The results strongly indicate that immunization with G. anatis OMVs provides significant protection against G. anatis challenge and induces specific antibody responses with high titers of OMV-specific IgY in serum. The results therefore show great promise for OMV based vaccines aiming at providing protecting against G. anatis in egg-laying hens.

Comprehensive N-Glycan Profiling of Avian Immunoglobulin Y.

Recent exploitation of the avian immune system has highlighted its suitability for the generation of high-quality, high-affinity antibodies to a wide range of antigens for a number of therapeutic and biotechnological applications. The glycosylation profile of potential immunoglobulin therapeutics is species specific and is heavily influenced by the cell-line/culture conditions used for production. Hence, knowledge of the carbohydrate moieties present on immunoglobulins is essential as certain glycan structures can adversely impact their physicochemical and biological properties. This study describes the detailed N-glycan profile of IgY polyclonal antibodies from the serum of leghorn chickens using a fully quantitative high-throughput N-glycan analysis approach, based on ultra-performance liquid chromatography (UPLC) separation of released glycans. Structural assignments revealed serum IgY to contain complex bi-, tri- and tetra-antennary glycans with or without core fucose and bisects, hybrid and high mannose glycans. High sialic acid content was also observed, with the presence of rare sialic acid structures, likely polysialic acids. It is concluded that IgY is heavily decorated with complex glycans; however, no known non-human or immunogenic glycans were identified. Thus, IgY is a potentially promising candidate for immunoglobulin-based therapies for the treatment of various infectious diseases.

Immunoglobulin detection in wild birds: effectiveness of three secondary anti-avian IgY antibodies in direct ELISAs in 41 avian species.

Immunological reagents for wild, non-model species are limited or often non-existent for many species.In this study, we compare the reactivity of a new anti-passerine IgY secondary antibody with existing secondary antibodies developed for use with birds. Samples from 41 species from the following six avian orders were analysed: Anseriformes (1 family, 1 species), Columbiformes (1 family, 2 species), Galliformes (1 family, 1 species), Passeriformes (16 families, 34 species), Piciformes (1 family, 2 species) and Suliformes (1 family, 1 species). Direct ELISAs were performed to detect total IgY using goat anti-passerine IgY, goat anti-chicken IgY or goat anti-bird IgY secondary antibodies.The anti-passerine antibody exhibited significantly higher IgY reactivity compared to the anti-chicken and/or anti-bird antibodies in 80% of the passerine families tested. Birds in the order Piciformes (woodpeckers) and order Suliformes (cormorants) were poorly detected by all three secondary antibodies. A comparison of serum and plasma IgY levels was made within the same individuals for two passerine species (house finch and white-crowned sparrow), and serum exhibited significantly more IgY than the plasma for all three secondary antibodies. This result indicates that serum may be preferred to plasma when measuring total antibody levels in blood.This study indicates that the anti-passerine IgY secondary antibody can effectively be used in immunological assays to detect passerine IgY for species in most passerine families and is preferred over anti-chicken and anti-bird secondary antibodies for the majority of passerine species. This anti-passerine antibody will allow for more accurate detection and quantification of IgY in more wild bird species than was possible with previously available secondary antibodies.

Evaluation of flagellum-related proteins FliD and FspA as subunit vaccines against Campylobacter jejuni colonisation in chickens

Campylobacter is the leading cause of food-borne diarrhoea in humans in the developed world and consumption of contaminated poultry meat is the main source of infection. Vaccination of broilers could reduce carcass contamination and zoonotic infections. Towards this aim, we evaluated recombinant anti-Campylobacter subunit vaccines based on the flagellum-capping protein FliD and the flagellum-secreted protein FspA as they are immunogenic in chickens and the flagellum is vital for colonisation. In three studies, a recombinant FliD vaccine induced a transient but reproducible and statistically significant decrease of c. 2log10CFU/g in caecal colonisation levels at 49 days post-primary vaccination on the day of hatch. Levels of serum IgY specific to FliD positively correlated with caecal bacterial counts in individual birds, indicating that such antibodies may not play a role in protection. The data add to the limited repertoire of candidate antigens for the control of a key foodborne zoonosis.

The screening and evaluation of herbs and identification of herbal combinations with anti-viral effects on Newcastle disease virus

A total of 25 “heat-clearing and detoxifying” herbs used in Chinese medicine were investigated for their cytopathic effects on the growth of Newcastle Disease virus (NDV) in a chicken fibroblast cell line.The 5 herbs with the highest virus inhibitory effects were Herba agastaches, Flos chrysanthemi indici, Rhizoma anemarrhenae, Astragalus root and Baikal skullcap root and these were used in herbal formulations. Anti-NDV activities of 4 formulations were tested on the growth of NDV in the DF-1 fibroblast cell line.Formulation II, containing Baikal skullcap root, Astragalus root, Anemarrhena rhizome (1:1:2) and formulation IV containing Anemarrhena rhizome, Astragalus root and Flos chrysanthemi indici (1:1:1), which had strong anti-NDV activity in vitro, were used to determine the in vivo inhibitory effects of NDV-infection in chickens. After treatment with the two formulations serum IgY titres against NDV were improved, and morbidity was reduced in the NDV-infected chickens.The results suggest that the components in formulations II and IV acted synergistically to improve resistance to Newcastle disease and provide a basis for the developing an anti-NDV herbal medicine.

Identification of the Avian Pasteurella multocida phoP Gene and Evaluation of the Effects of phoP Deletion on Virulence and Immunogenicity.

Pasteurella multocida (P. multocida) is an animal pathogen of worldwide economic significance that causes fowl cholera in poultry and wild birds. Global gene regulators, including PhoP are important in regulating bacterial virulence and are good targets for developing attenuated vaccines against many pathogenic bacteria. However, the biological significance of phoP gene has not been identified in P. multocida. Here, we identified the phoP gene in P. multocida, and we evaluated the roles of phoP in P. multocida by deleting the phoP gene. The P. multocida phoP mutant exhibited similar growth curves and lipopolysaccharide and outer membrane protein profiles but displayed defective polymyxin resistance in vitro compared with the parent strain. Additionally, the phoP deletion resulted in decreased virulence. The LD50 of the ΔphoP mutant was 32- and 154-fold higher than the parent strain via the oral and intranasal routes, respectively. Transcriptome sequencing analysis showed that 161 genes were up-regulated and 173 genes were down-regulated in the absence of the phoP gene. Finally, the immunogenicity and protective efficacy of the ΔphoP mutant were evaluated. Immunized ducks produced significantly higher levels of serum IgY and bile IgA compared to the control ducks, and immunization with the ΔphoP mutant conferred 54.5% protection efficiency against challenge with the virulent P. multocida. This work provides a platform to dissect the function of phoP and develop a new vaccine against P. multocida.

The effect of dietary fructooligosaccharide supplementation on growth performance, intestinal morphology, and immune responses in broiler chickens challenged with Salmonella Enteritidis lipopolysaccharides

This study was conducted to examine the effects of fructooligosaccharide (FOS) supplementation on growth performance, lymphoid organ weight, intestinal morphology, and immunological status in broilers (n = 180) challenged with Salmonella Enteritidis lipopolysaccharides (LPS). Birds were randomly assigned into a 3 × 2 factorial arrangement that included 1) 3 dietary treatments from d one to 21: positive control (PC), wheat-corn-soybean meal based diet contained antibiotics (virginiamycin and monensin); negative control (NC), as PC without antibiotics; and NC + FOS, as NC supplemented with 0.5% FOS, and 2) 2 intraperitoneal injections: 2 mg/kg Salmonella Enteritidis LPS or sterile phosphate buffered saline (PBS) on d 21. Growth performance and relative lymphoid organ weight were not significantly different among the treatments. Villus height, crypt depth, and total mucosa thickness were significantly increased (P < 0.05) in the ileum of broiler chickens fed NC + FOS when compared to PC and NC. Birds in NC + FOS treatment had reduced heterophil but increased monocyte count when compared to NC (P < 0.05). Significant diet × challenge interaction was observed on natural IgY levels (P < 0.0001), and a significant dietary effect was observed on specific IgY levels in chickens fed NC + FOS (P = 0.003). Supplementation of FOS also increased the expression of interleukin (IL)-1ß, -10, and interferon (IFN)-γ mRNA in the ileum of the birds. In summary, Salmonella Enteritidis LPS challenge established significant differences in the immune responses in broiler chickens. FOS supplementation increased ileal mucosa thickness and elevated the expressions of certain cytokine genes. It also led to the alteration of leukocyte compositions and serum IgY levels in response to LPS challenge, suggesting FOS supplementation may be effective to induce protective outcomes in gut health and immunity of broiler chickens.

Superoxide dismutase SodB is a protective antigen against Campylobacter jejuni colonisation in chickens

Campylobacter is the leading cause of foodborne diarrhoeal illness in the developed world and consumption or handling of contaminated poultry meat is the principal source of infection. Strategies to control Campylobacter in broilers prior to slaughter are urgently required and are predicted to limit the incidence of human campylobacteriosis. Towards this aim, a purified recombinant subunit vaccine based on the superoxide dismutase (SodB) protein of C. jejuni M1 was developed and tested in White Leghorn birds. Birds were vaccinated on the day of hatch and 14 days later with SodB fused to glutathione S-transferase (GST) or purified GST alone. Birds were challenged with C. jejuni M1 at 28 days of age and caecal Campylobacter counts determined at weekly intervals. Across three independent trials, the vaccine induced a statistically significant 1 log10 reduction in caecal Campylobacter numbers in vaccinated birds compared to age-matched GST-vaccinated controls. Significant induction of antigen-specific serum IgY was detected in all vaccinated birds, however the magnitude and timing of SodB-specific IgY did not correlate with lower numbers of C. jejuni. Antibodies from SodB-vaccinated chickens detected the protein in the periplasm and not membrane fractions or on the bacterial surface, suggesting that the protection observed may not be strictly antibody-mediated. SodB may be useful as a constituent of vaccines for control of C. jejuni infection in broiler birds, however modest protection was observed late relative to the life of broiler birds and further studies are required to potentiate the magnitude and timing of protection.

Effects of 5-hydroxytryptophan and m-hydroxybenzylhydrazine associated to Lactobacillus spp. on the humoral response of broilers challenged with Salmonella Enteritidis

This study investigates the effects of different doses of serotonin, its precursor 5-hydroxytry-ptophan (5HTP), and m-hydroxybenzylhydrazine inhibitor (NSD1015), administered via intraperitoneal for 5 consecutive days, on behavior and average body weight of broilers. We also measured the humoral immune response and quantification of Salmonella Enteritidis in broilers chickens that received the drugs evaluated and a Lactobacillus pool. The study was divided into 3 experiments: Experiment 1 - administration of pharmaceuticals with choice of dosage; Experiment 2 - administration of pharmaceuticals and a Lactobacillus pool in birds that were not challenged with S. Enteritidis, and Experiment 3 - administration of pharmaceuticals and a Lactobacillus pool in birds challenged with S. Enteritidis. The ELISA was used to scan dosages of intestinal IgA and serum IgY. We used colony-forming units to quantify S. Enteritidis. The concentrations of IgA and IgY did not show significant differences (P > 0.05) in Experiment 2. In Experiment 3, NSD1015 associated with Lactobacillus determined higher IgA concentrations, promoting greater stimulus to the immune system than 5HTP. Regarding quantification of S. Enteritidis in the cecal content of birds, 5HTP associated to Lactobacillus determined the smallest number of bacteria, showing possible interaction of 5-hydroxytryptophan and Lactobacillus spp. with the immune system of broiler chickens.

Live and Inactivated &amp;lt;i&amp;gt;Salmonella&amp;lt;/i&amp;gt; Enteritidis Vaccines: Immune Mechanisms in Broiler Breeders

Salmonella is a ubiquitous pathogen which, in addition to causing poultry diseases, has a growing zoonotic impact. It has demanded the implementation of diverse control strategies, in which vaccines play a major role. The understanding of the immune pathways elicited by the different vaccines is important, contributing for the establishment of strong immune correlates of protection, for instance. With the purpose of determining the dynamics of the humoral and cellular immune responses to vaccination, broiler breeders (Cobb Slow) were immunized with live or inactivated vaccines against Salmonella Enteritidis. Lymphocyte and macrophage subsets were analyzed in the peripheral blood by flow cytometry and antigen-specific circulating IgY and mucosal IgA were quantified. The markers analyzed by flow cytometry were CD8/CD28, CD4/TCRVβ1, Kul/ MHC II and Bu-1. Both live and inactivated vaccines induced an increase in the proportion of circulating monocytes (Kul+MHCII+) in some time points compared to non-vaccinated controls. However, whereas the live vaccine leads to an increase in CD8-CD28+ and Bu-1+ lymphocytescompared to the control group, the inactivated vaccine prompteda reduction in the percentage of severalleucocyte subsets (Kul-MHCII+, Bu-1+, CD8+CD28+, CD8-CD28+, CD4+TCRVβ1-, CD4+TCRVβ1+, CD4-TCRVβ1+) after the boost dose. Both vaccines induced specific serum IgY and mucosal IgA production; however, the inactivated vaccine stimulated higher titers in a shorter period. These results contribute to the understanding of mechanisms of action of live and inactivated Salmonella vaccines in chickens.

B lymphocytes activation in GALT (Gut Associated Lymphatic Tissue) in immunized hens with Escherichia coli K88.

B lymphocytes activation in GALT (Gut Associated Lymphatic Tissue) in immunized hens with Escherichia coli K88.

Immunological and biochemical indicators in turkeys fed diets with a different Methionine content.

The objective of this study was to determine the effect of different levels of dietary methionine on selected immune parameters of young turkeys. A total of 357 one-day-old female Hybrid Converter turkeys were randomly divided into three groups with low, medium and high level of dietary me- thionine (LM, MM, HM) of seven replicates each. Methionine was added to the basal diet (LM) at 0.16% (MM) and 0.32% (HM). At 17 days of age, seven birds per group were vaccinated against Ornithobacterium rhinotraheale (ORT) infection, with ORNITIN (ABIC) vaccine. At 28 days of age, blood was sampled and the birds were euthanized. The serum concentrations and activity of selected biochemical parameters, total IgY and IgM, and vaccine-induced antibody titers (IgY) against ORT were determined. The percentages of CD4+, CD8+, CD4+/CD8+ T cell subpopulations and IgM+ B cell subpopulation were determined in blood and organs by flow cytometry. Different supplementary levels of methionine had no significant effect on vaccine-induced anti- body titers against ORT or total serum IgM and IgY levels, as well as on the percentages of periph- eral blood T and B cell subsets. Increasing dietary methionine rates decreased the percentage of CD4+ T cell subpopulation, however it has increased the percentage of IgM+ B cell subpopulation in the spleen. Vaccination against ORT resulted in a significant decrease in the percentage of CD4+ T cell subset and an increase in the percentage of CD8+ T cell subset in the spleen. It could be concluded that MM turkeys have developed the most desirable values of immune parameters.

Chronobiological studies of chicken IgY: Monitoring of infradian, circadian and ultradian rhythms of IgY in blood and yolk of chickens

IgY is the functional equivalent of mammalian IgG found in birds, reptiles and amphibians. Many of its biological aspects have been explored with different approaches. In order to evaluate the rhythmicity of serum and yolk IgY, four chickens were examined and reared under the same conditions. To monitor biological oscillations of IgY in yolk and serum, the eggs and blood samples were collected over a 60 day period and the rhythm of yolk and serum IgY was determined by direct-ELISA. Results indicated that, there is a significant circaseptan rhythm in yolk IgY and circaquattran rhythm in serum IgY. The serum IgY concentration reached a peak in the morning, decreased to a minimum during the daytime and increased again at night revealing a significant circadian rhythm was superimposed by an ultradian rhythm. These data are suited to address the controversies concerning the IgY concentration in egg yolk and blood of laying hens. In addition, this study raised new questions, if the different rhythms in yolk and serum are concerned.