Yolk IgY Research Articles

Egg yolk IgY: Protection against rotavirus induced diarrhea and modulatory effect on the systemic and mucosal antibody responses in newborn calves

Bovine rotavirus (BRV) is an important cause of diarrhea in newborn calves. Local passive immunity is the most efficient protective strategy to control the disease. IgY technology (the use of chicken egg yolk immunoglobulins) is an economic and practical alternative to prevent BRV diarrhea in dairy calves. The aim of this study was to evaluate the protection and immunomodulation induced by the oral administration of egg yolk enriched in BRV specific IgY to experimentally BRV infected calves. All calves in groups Gp 1, 2 and 3 received control colostrum (CC; BRV virus neutralization Ab titer – VN = 65,536; ELISA BRV IgG 1 = 16,384) prior to gut closure. After gut closure, calves received milk supplemented with 6% BRV-immune egg yolk [(Gp 1) VN = 2048; ELISA IgY Ab titer = 4096] or non-immune control egg yolk [(Gp 2) VN < 4; ELISA IgY Ab titer < 4] twice a day, for 14 days. Calves receiving CC only or colostrum deprived calves (CD) fed antibody (Ab) free milk served as controls (Gp 3 and 4, respectively). Calves were inoculated with 10 5.85 focus forming units (FFU) of virulent BRV IND at 2 days of age. Control calves (Gp 3 and 4) and calves fed control IgY (Gp 2) were infected and developed severe diarrhea. Around 80% calves in Gp 1 (IgY 4096) were infected, but they showed 80% (4/5) protection against BRV diarrhea. Bovine RV-specific IgY Ab were detected in the feces of calves in Gp 1, indicating that avian antibodies (Abs) remained intact after passage through the gastrointestinal tract. At post infection day 21, the duodenum was the major site of BRV specific antibody secreting cells (ASC) in all experimental groups. Mucosal ASC responses of all isotypes were significantly higher in the IgY treated groups, independently of the specificity of the treatment, indicating that egg yolk components modulated the immune response against BRV infection at the mucosal level. These results indicate that supplementing newborn calves’ diets for the first 14 days of life with egg yolk enriched in BRV-specific IgY represents a promising strategy to prevent BRV diarrhea. Moreover a strong active ASC immune response is induced in the intestinal mucosa following BRV infection after the administration of egg yolk, regardless the specificity of the treatment.

COMPETITIVE AND DOUBLE ANTIBODY SANDWICH ELISA FOR THE QUANTIFICATION OF LACTOFERRINS BY USING MONOCLONAL AND CHICKEN EGG YOLK IgY ANTIBODIES

Two effective competitive and double antibody sandwich ELISA based on monoclonal (MAb) and chicken egg yolk IgY antibodies were developed to determine lactoferrin (LF) content in infant and milk formulas. Leghorn laying hens were immunized with purified bovine and human LFs to produce anti-bovine LF and anti-human LF IgY antibody in the egg yolk. After 5–8 weeks of the immunization, anti-LF IgY was extracted and analyzed by ELISA. Specific IgY antibodies against LFs cross reacted with human and bovine LFs, examined by ELISA and western-blot assay. Such cross-reactivity suggested the presence of common antigenic determinants between human and bovine LFs. An indirect competitive ELISA was preferred to quantify LF in milk and infant formulas, since the range of detection is 3.125–50 μg/mL, which is broader compared to the biotinylated ELISA system (5–50 ng/mL). As per the indirect competitive ELISA system, IgY at a concentration of the 150 μg/mL was incubated with various concentrations of bovine LF ranged from 0.003–100 μg/mL. The immunoassay was used to estimate the total bovine LF content in the milk samples and infant formulas, ranging from 49.28–80.96 μg/mL and 29.92–60.00 μg/mL, respectively.

Passive protection of purified yolk immunoglobulin administered against Shiga toxin 1 in mouse models

Shiga toxins produced by Escherichia coli O157:H7 cause a wide spectrum of enteric diseases, such as lethal hemorrhagic colitis and hemolytic uremic syndrome. In this study, the B subunit protein of Shiga toxin type 1 (Stx1) was produced in the E. coli system, was further purified by Ni-column Affinity Chromatography method, and was then used as an immunogen to immunize laying hens for yolk immunoglobulin (IgY) production. Titers of IgY increased gradually with boosting vaccination and, finally, reached a level of 105, remaining steady over 1 year. Then the protective efficacy of IgY against Stx1 was evaluated by in vitro and in vivo experiments. It was shown that the anti-Stx1 IgY could effectively block the binding of Stx1 to the Hela cells and could protect BALB/c mice from toxin challenges. The data indicates the facility of using egg yolk IgY as a therapeutic intervention in cases of Shiga toxin intoxication.

Effect of Selenium-enriched Japanese Radish Sprouts and Rhodobacter capsulatus on the Cholesterol and Immune Response of Laying Hens

Immune response and yolk cholesterol are crucial factors for commercial chicken producers. The objectives of this study were to investigate the effect of selenium-enriched Japanese radish sprouts (Se-enriched JRS) and R. capsulatus synergistically on immune response and cholesterol in laying hens. A total of 50 laying hens (20-wk old) were assigned to 5 dietary treatment groups, and fed diets supplemented with 2.5 μg/kg, 5 μg/kg, 10 μg/kg Se-enriched JRS and 5 μg/kg Se-enriched JRS+R. capsulatus (0.02%). Egg production and yolk color were significantly improved by the supplementation of Se-enriched JRS+R. capsulatus in the layer diet (p<0.05). Compared to the control, serum cholesterol concentration and triglyceride levels were decreased by all the treatments (p<0.05). After 8-wk of the experiment, supplementation of 5 μg/kg, 10 μg/kg and Se-enriched JRS+R. capsulatus significantly reduced yolk cholesterol and triglycerides, while the greatest reduction was observed when R. capsulatus was incorporated with Se-enriched JRS. Spleen, bursa and thymus weight were significantly increased by both the 5 μg/kg and 10 μg/kg Se-enriched JRS. Compared to the control, supplementation of 5 μg/kg and 10 μg/kg Se-enriched JRS significantly increased serum IgG and yolk IgY concentration and foot web index activity by Newcastle Disease Virus (p<0.05). After 4-wk and 8-wk of supplementation, the highest number of leukocytes was observed with Se-enriched JRS+R. capsulatus (p<0.05). The highest concentration of serum and yolk Se was found in Se-enriched JRS plus R. capsulatus treatment. Combined dietary supplementation of Se-enriched JRS and R. capsulatus might be beneficial for better health, disease protection and overall production performance.

Effect of dietary available phosphorus and organic acids on the performance and egg quality of laying hens

SUMMARY Phosphorus is essential for the growth of poultry, particularly for bone development. Eighty percent or more of the total P is in the form of phytate. Monogastrics, such as chickens and pigs, do not secrete the enzyme that breaks down phytates and separates P in grains or oil meals. Organic acids (OA) effectively check the growth of mold and bacteria. Furthermore, adding OA to feed can lower the gastric pH. Low gastric pH accelerates the conversion of pepsinogen to pepsin, which improves the absorption rate of proteins, amino acids, and minerals. This experiment was performed to examine the effect of adding OA to feeds with different available P (AP) levels in terms of egg productivity, egg quality, and IgY levels. Results suggest that the AP level in feed does not have to be higher than 0.3%, when compared with 0.4% AP in the diet. Supplementation of 0.2% OA to the 0.3% AP diet showed the best results in hen-housed egg production, soft-shell plus broken egg production, FCR, and egg yolk IgY. However, the best eggshell color was obtained in the 0.4% AP and 0.2% OA diet.

Differences in usability of rabbit IgG and chicken IgY after clean-up and impact on gold labelling properties

For the application of antibodies in rapid test systems such as Lateral Flow Devices (LFD) antibodies have to be coupled to coloured particles for immediate readability of the test system. In this work colloidal gold was selected for conjugation to the antibodies. Polyclonal rabbit antibodies were chosen for the development of Lateral Flow Devices for the detection of bovine α-casein. For antibody comparison chicken egg yolk IgY and sheep IgG were additionally used. Rabbit and chicken antibodies were purified from rabbit sera and egg yolk using affinity chromatography and alternatively ammonium sulphate precipitation, Sheep IgG was commercially obtained. In the course of colloidal gold sol titration experiments differences not only between antibody species but also between differently purified rabbit IgG were observed. While affinity purified rabbit IgG was not able to stabilise colloidal gold particles, antibodies obtained by ammonium sulphate precipitation resulted in a stable gold conjugate suitable for application in Lateral Flow Assays. This work compares and discusses the impact of antibody pre-treatment on further conjugation capacity.

Protective effect of hyperimmune egg yolk IgY antibodies against Eimeria tenella and Eimeria maxima infections

Avian coccidiosis is caused by several distinct species of Eimeria protozoa and is the major parasitic disease of poultry of economic importance. As an alternative strategy to control avian coccidiosis without using prophylactic medications, we have investigated the efficacy of inducing passive immunity against coccidiosis by orally feeding hyperimmune IgY antibodies. In this study, a commercially available egg yolk powder, Supracox® (SC), a purified IgY fraction of egg yolk prepared from hens hyperimmunized with three major species of Eimeria oocysts, were continuously fed to young chicks from hatch. Upon orally infecting these broiler chicks with Eimeria tenella and Eimeria maxima oocysts at 1 week of age, they showed significantly higher body weight gains (P<0.05) compared to the untreated controls. Furthermore, SC-fed chicks showed significantly less intestinal lesions and reduced fecal oocyst output compared to the untreated controls following oral infections with E. tenella and E. maxima. These results provide clear evidence that passive immunization of chicks with hyperimmune egg yolk IgY antibodies provide significant protection against E. tenella or E. maxima infections.

The Effect of Different Feed Restriction Programs and Dietary L-Carnitine Supplementation on Hepatic Lipogenesis, Plasma Heterophil to Lymphocyte Ratio and Yolk IgY Content of Broiler Breeder Hens

Two experiments were conducted to determine effects of Everyday (ED) or Skip-a-day (SK) feeding and dietary L-carnitine on lipid metabolism and stress in broiler breeders. In Experiment 1 a 2x2 factorial design was used to compare feeding regimens (ED vs SK) and L-carnitine supplementation (0 vs 50 mg/kg). L-carnitine supplementation began at d 1 and lasted throughout the 45 weeks experimental period. SK programs were implemented from 28 days of age to 5% production. Parameters measured included in vitro Lipogenesis (IVL), Heterophil/Lymphocyte ratio (H/L) and yolk IgY content. Liver and blood samples were taken 1 h after feeding, at various intervals during the rearing and production periods. Both SK feeding and L-carnitine increased liver wts during rearing but differences dissipated after onset of lay. Part of the increase in liver weight in SK birds was due to higher lipid contents. L-carnitine tended to reduce liver lipid during rearing. IVL was increased by SK feeding during the rearing period. L-carnitine and SK feeding interacted to increase IVL at 20, 22 and 27 weeks. H/L was elevated at 7 weeks in SK birds, but no differences were observed after that. Neither L-carnitine nor feeding regimens affected maternal IgY transfer to egg yolks. In Experiment 2, the same effects were tested but a low density grower diet was used from 4-18 weeks. The grower diet had 9% less energy and 7% less protein than in experiment 1. Liver wt was increased in SK and L-carnitine supplemented birds up to 20 weeks. By 40 weeks, ED birds had higher liver weights than SK. Liver fat was generally higher in SK birds than ED during rearing. SK feeding increased IVL but unlike Experiment 1, L-carnitine did not. H/L ratio was elevated in SK up to 20 weeks of age after which no differences occurred. L-carnitine did not affect H/L. In conclusion, feeding regimens and L-carnitine can alter hepatic lipid synthesis. Feeding regimens like SK, incorporating lengthy periods without feed can result in elevated H/L ratios but birds are generally able to adapt to such regimens over time.

Single-Chain Antibody Fragments from a Display Library Derived from Chickens Immunized with a Mixture of Parasite and Viral Antigens

Phage-displayed chicken single-chain antibody fragment libraries can provide useful diagnostic and research reagents. Using avian immunoglobulin genes simplifies the construction of such repertoires since far fewer primer sets are required to access the avian antibody repertoire than is the case with mice or humans. Libraries constructed using mRNA from an immune source are enriched in affinity-matured sequences and consequently need not be as large as "universal" non-immune repertoires to have a reasonable probability of yielding high-affinity binders. Repertoires focused on a number of defined targets can be constructed using lymphocyte mRNA from chickens immunized with a mixture of several different antigens. This approach was evaluated with the aim of economically and rapidly deriving immunodiagnostic reagents for malaria, trypanosomiasis, and malignant catarrhal fever, all of which are important to health or food security in Africa. Two chickens were each immunized with a mixture comprised of recombinantly expressed histidine-rich protein, the aldolase and the lactate dehydrogenase of Plasmodium falciparum, the variant surface glycoprotein of Trypanosoma sp., and purified malignant catarrhal fever virus, a herpesvirus that causes an economically important disease of cattle and other ruminants. Immune responses to each of the individual antigens were determined by extracting egg-yolk IgY and testing for antigen-specific antibodies in ELISA. The chicken splenocytes were then recovered, RNA was extracted, and after reverse transcription, the immunoglobulin VH and VL regions were amplified by PCR and joined via a single glycyl residue for surface expression on a collection of filamentous bacteriophages. The resulting display library was then screened by panning to isolate binders. The immunized chickens did not, however, respond equally well to all the different antigens, nor was it possible to derive antibody fragments against all the targets. These limitations notwithstanding, several useful binders with the potential to be used in malaria diagnosis were obtained.

The Chicken Yolk Sac IgY Receptor, a Mammalian Mannose Receptor Family Member, Transcytoses IgY across Polarized Epithelial Cells

In mammals the transfer of passive immunity from mother to young is mediated by the MHC-related receptor FcRn, which transports maternal IgG across epithelial cell barriers. In birds, maternal IgY in egg yolk is transferred across the yolk sac to passively immunize chicks during gestation and early independent life. The chicken yolk sac IgY receptor (FcRY) is the ortholog of the mammalian phospholipase A2 receptor, a mannose receptor family member, rather than an FcRn or MHC homolog. FcRn and FcRY both exhibit ligand binding at the acidic pH of endosomes and ligand release at the slightly basic pH of blood. Here we show that FcRY expressed in polarized mammalian epithelial cells functioned in endocytosis, bidirectional transcytosis, and recycling of chicken FcY/IgY. Confocal immunofluorescence studies demonstrated that IgY binding and endocytosis occurred at acidic but not basic pH, mimicking pH-dependent uptake of IgG by FcRn. Colocalization studies showed FcRY-mediated internalization via clathrin-coated pits and transport involving early and recycling endosomes. Disruption of microtubules partially inhibited apical-to-basolateral and basolateral-to-apical transcytosis, but not recycling, suggesting the use of different trafficking machinery. Our results represent the first cell biological evidence of functional equivalence between FcRY and FcRn and provide an intriguing example of how evolution can give rise to systems in which similar biological requirements in different species are satisfied utilizing distinct protein folds.

Prevention of Salmonella Infection in Poultry by Specific Egg-Derived Antibody

Salmonella enteritidis (SE) colonizes the intestinal tract of poultry and causes food born illness in humans. Reduction of (SE) colonization in the intestinal tract of poultry reduces potential carcass contamination during slaughter. The purpose of this study was to investigate the effect of SE-specific yolk immunoglobulin (IgY) on prevention of SE colonization in orally infected broiler chickens. Commercial Single Comb White Leghorn (SCWL) hens were hyperimmunized with SE whole cell antigens. The presence of anti-Salmonella antibody, IgY and IgG in egg yolk and serum respectively, was monitored by Enzyme Linked Sorbent Assay (ELISA). Two hundred forty male `Ross 308` day old chicks were randomly assigned to 8 groups and 3 replications of 10 birds were grown for 42 days of experiment. Eight experimental groups identified with, S, P, A, SP, SA, AP, SPA, C. Four birds from four challenged groups (S), were orally inoculated with 1 mL of bacterial suspension that contained 1×106 CFU mL-1 S. enteritidis at 3 day of age. The groups that supplemented with antibody (A) received 15 mL of yolk contained antibody mixed per 3.84 mL of drinking water on day 1 and continuing for duration of the experiment. The probiotic treated groups (P) were received probiotic, 0.1% of feed and 0.5% of feed, until day 21 and 56 respectively. One group as control (C) did not received any treatment of probiotic and antibody. A-treated and A-P treated groups had significantly lower fecal shedding (p<0.01) and lower concentration of SE cecal colonization (p<0.01). These groups also had a lower isolation of SE from the liver, spleen and ileum. The use of Salmonella enteritidis-specific IgY combined with probiotic had a beneficial effect in reducing the colonization of Salmonella in market-aged broiler under the condition of this study.

Immunoglobulin glycation with fructose: A comparative study

Background Immunoglobulins undergo non-enzymatic glycation reaction with sugars both in vivo and in vitro. Effects of glycation on the ability of the antibodies to bind antigens are contradictory. Antibodies raised in various animals may also be exposed to high concentration of sugars that are added during freeze-drying/pasteurization for preservation. Methods IgG isolated from the sera of goat, human, rabbit, mouse, buffalo as well as IgY from hen egg yolk was subjected to in vitro glycation with fructose. The behavior of glycated IgG was investigated by SDS-PAGE, hyperchromicity at 280 nm, tryptophan fluorescence and new fluorescence. Results Marked variations were observed in the response of the immunoglobulins derived from various animals to incubation with fructose. Also, incubation of anti-glucoseoxidase (GOD) antibodies with fructose resulted in a rapid loss of their ability to bind the enzyme antigen as revealed by immunodiffusion and ELISA. DETAPAC and EDTA were quite protective but were unable to completely prevent the fructose-induced alterations. Conclusions Immunoglobulins derived from goat, human, rabbit, mouse, buffalo and hen egg yolk undergo remarkable structural alterations on incubation with fructose. The susceptibility of the immunoglobulins to the modification however differed remarkably. The goat IgG was most recalcitrant while hen egg yolk IgY was most susceptible to the alterations. DETAPAC or EDTA restricted the fructose-induced alterations remarkably.

Maternal Antibody Transfer from Dams to Their Egg Yolks, Egg Whites, and Chicks in Meat Lines of Chickens

Maternal antibodies are transferred from hens to the chicks via the egg. To gain insight into maternal antibody transfer and endogenous production of antibodies in broiler chicks, total IgY, IgA, IgM, as well as anti-Newcastle disease virus (NDV) and anti-infectious bronchitis (IBV) antibody levels were examined in the dams’ plasma, egg yolks, egg whites, and chicks’ plasma on d 3, 7, 14, and 21. Blood was collected from 39-wk-old breeder hens (line 1, n = 17; line 2, n = 21). Fertile eggs were used for antibody extraction from the egg yolks and egg whites (4 to 5 eggs/dam) and for hatching. Unvaccinated chicks (4 to 5 chicks/dam) were reared in a HEPA-filtered room and were bled on d 3, 7, 14 and 21. Based on ELISA methods, plasma levels of IgY and IgM were higher (P < 0.0001), and those of IgA were similar (P = 0.31), in line 2 compared with line 1. Egg yolk IgY and IgA, as well as egg white IgY, IgA, and IgM levels were higher in line 2 compared with line 1 (P < 0.0001). Independent of line of chicken, the percentage dam-to-chick (3 d) plasma transfer of IgY was estimated to be approximately 30%, with that for IgM and IgA less than 1%. Chicks synthesized IgM first, followed by IgA and IgY. Anti-NDV and anti-IBV antibodies were detected in the dams’ plasma, egg yolks, and in the chicks’ plasma on d 3 and 7, with line 2 having higher anti-IBV and lower anti-NDV levels than line 1 in all samples (P < 0.0001). In summary, IgY levels, total or antigen-specific, in the dams’ plasma or eggs were found to be a direct indicator of maternal antibody transfer to the chicks’ circulation, with an expected percentage transfer of approximately 30%. This knowledge, together with the observed time course of endogenous antibody production in broiler chicks, may find direct application in formulating strategies for protecting chicks, especially during the first few weeks of age when their immune system is not yet fully functional.

Orally administered anti-Escherichia coli O157:H7 chicken egg yolk antibodies reduce fecal shedding of the pathogen by ruminants

Spray-dried whole egg prepared from eggs laid by non-immunized hens (EG) or hens immunized with the C-terminal domain of Escherichia coli O157:H7 intimin (EG-IgY) was fed to experimentally inoculated sheep, to investigate the efficacy of orally administered polyclonal anti-E. coli O157:H7 antibodies (IgY) for reducing the duration and level of fecal shedding of E. coli O157:H7 by ruminants. Thirty Canadian Arcott ram lambs were orally inoculated on day 0 with 1010 colony-forming units (CFU) of a three-strain mixture of nalidixic acid-resistant E. coli O157:H7. On each of days 2, 3 and 4, the rams (n = 6) were fed 100 g of EG and/or EG-IgY in proportions of 100:0 (CON), 0:100 (HIGH), 50:50 (MED), or 75:25 (LOW). A fifth treatment (denoted variable, VAR) comprised feeding HIGH, MED and LOW on days 2, 3, and 4, respectively. Fecal samples collected on 19 occasions over 85 d (4 × in the first wk; 2×/wk for 3 wk; and 1×/wk for 9 wk) were assessed for E. coli O157:H7 by direct plating or enrichment and immunomagnetic separation. Throughout the 85 d, numbers of E. coli O157:H7 shed by the rams were lower (P &lt; 0.001) in HIGH and MED than in CON, and the duration of shedding was shorter (P &lt; 0.005) in HIGH than in CON. Fewer (P &lt; 0.005) samples were culture-positive in HIGH than in CON. Oral dosing of specific IgY has potential to decrease the duration and level of fecal shedding of E. coli O157:H7 by ruminants. Key words: E. coli O157:H7, egg-yolk IgY, fecal shedding, immunotherapy, ruminants, sheep

Significance of local immunity in hen reproductive organs

ABSTRACTThe current paper describes aspects of local immunity in the ovary and oviduct, and the significance of immunity to reproductive functions in hens. The immunocompetent cell populations in the ovary and oviduct change with a positive correlation to sexual activity, and gonadal steroid is one of the key factors in the increase. Local immune responses mediated by major histocompatibility complex class II and T cell subsets occur in response to infection by Salmonella enteritidis, which may contaminate eggs. In the ovary, immunocompetent cells are also suggested to play roles in the regulation of ovarian functions. Macrophages and T cells are likely to enhance the regression of atretic follicles to maintain the ovarian tissue microenvironment. Autoantibodies to ovarian tissues appeared in the hens with low egg laying frequency, suggesting that the auto‐antibodies may be one of the factors in the decline of egg production. In the oviduct, local immunity possibly has a role in the selection of sperm, though the immunoreactions may also affect sperm survival leading to the decline in fertility. The concentration of yolk IgY, which plays a role in maternal immunity transmission, significantly decreases with the aging of birds, whereas it is significantly increased by estrogen. Therefore, the immune system plays significant roles not only in defense against infection, but also in the functions of reproductive organs. Investigations on the local immune system in the reproductive organs and factors affecting it are of importance for the production of sterile eggs and improvement of reproductive functions.

Biologically Active Hen Egg Components in Human Health and Disease

It is widely recognized that eggs are more than a source of dietary nutrients, and extensive studies identifying and characterizing the biologically active components of eggs have been carried out. Numerous biological activities have now been associated with egg components, including antibacterial and antiviral activity, immunomodulatory activity, and anti-cancer activity, indicating the importance of eggs and egg components in human health, and disease prevention and treatment. The potential of some of these biologically active components has already been realized, including egg white lysozyme and avidin, and yolk IgY and lecithin, which are currently produced on an industrial scale, and have been applied for the prevention and treatment of various medical conditions. The information presented here serves to demonstrate the significant potential of biologically active egg components, for medical, nutraceutical, and food-fortification applications.

Purification of antibody Fab and F(ab ′) 2 fragments using Gradiflow technology

The Gradiflow, a preparative electrophoresis instrument designed to separate molecules on the basis of their size and charge, was used to purify antibody Fab and F(ab ′) 2 fragments. The method described is charge based, utilizing the difference in the p I between the antibody Fab/F(ab ′) 2 fragments and antibody Fc fragments that occur after enzyme digestion of whole antibody molecules. This method of purification was successful across a range of monoclonal and polyclonal antibodies. In particular, F(ab ′) 2 fragments were purified from a number of mouse monoclonal antibodies (both IgG1 and IgG2a isotypes) and Fab fragments were purified from egg yolk IgY polyclonal antibodies. This is a rapid purification method which has advantages over alternative methods that usually comprise ion exchange and gel filtration chromatography. This method may be applicable to most antibody digest preparations.

Effect of beta-carotene supplementation on plasma and yolk IgY levels induced by NDV vaccination in Japanese quail.

Newly hatched Japanese quail (Coturnix coturnix japonica) chicks were fed diets containing different levels of retinoids (vitamin A) or beta-carotene. Group A received a commercial diet containing 10,000 IU vitamin A per kilogram. The diets of Groups B, C, and D contained no vitamin A but were supplemented with 1-, 2.5-, and 5-fold retinol equivalents of beta-carotene. Each group contained 16 quails in a 1:1 sex ratio. At 8 weeks of age the quails were immunized orally with Newcastle disease virus (NDV) vaccine according to the manufacturer's recommendations. Boosters were given three times at two-week intervals. Blood samples were taken at two-week intervals until 14 weeks of age. The anti-NDV IgY titre was determined by a locally developed direct enzyme-linked immunosorbent assay (ELISA). Groups A and B showed nearly the same antibody response. This indicates that the preformed vitamin A and the equivalent beta-carotene have the same immunomodulatory effect. Groups receiving higher doses of beta-carotene (Groups C and D) exhibited significantly higher plasma IgY levels compared to Groups A and B. The results indicate that elevated doses of beta-carotene have a slight effect on the adaptive immune response in Japanese quail.

Immunoglobulin Y Levels in Egg Yolk From Three Chicken Genotypes

Laying hens are very efficient producers of antibodies and provide an interesting alternative for large-scale production of specific antibodies. These antibodies also have biochemical advantages over mammalian antibodies (e.g. rabbit antibodies) that can be used to improve immunoassays where antibodies are used. The concentration of IgY in egg yolk is an important production parameter. The purpose of this study was to investigate the genetic variation of IgY levels in egg yolk. We have compared IgY concentrations in egg yolks from two lines, selected for egg production traits at the Swedish University for Agricultural Sciences (Single Comb White Leghorn and Rhode Island Red) and a cross between the two lines (SLU-1392). Single Comb White Leghorns have the highest mean concentration of yolk IgY, 2.21 mg ml−1 compared to SLU-1392 1.95 mg ml−1 and Rhode Island Red 1.68 mg ml−1. The cross thus had an intermediate IgY concentration in relation two the two other lines. There were great differences between individual animals within each line. Our results indicate that it should be possible to increase yolk antibody production by using a high producing chicken line and by genetic selection within the line. We found three individuals with very low yolk IgY concentrations among the Rhode Island Red hens. Newly hatched chickens with limited amounts of IgY from the hen may be more susceptible to infections.

Use of egg yolk-derived immunoglobulin as an alternative to antibiotic treatment for control of Helicobacter pylori infection.

The present study evaluated the potential use of immunoglobulin prepared from the egg yolk of hens immunized with Helicobacter pylori (immunoglobulin Y [IgY]-Hp) in the treatment of H. pylori infections. The purity of our purified IgY-Hp was 91.3%, with a yield of 9.4 mg of IgY per ml of egg yolk. The titer for IgY-Hp was 16 times higher than that for IgY in egg yolk from nonimmunized hens, and IgY-Hp significantly inhibited the growth and urease activity of H. pylori in vitro. Bacterial adhesion on AGS cells was definitely reduced by preincubation of both H. pylori (10(8) CFU/ml) and 10 mg of IgY-Hp/ml. In Mongolian gerbil models, IgY-Hp decreased H. pylori-induced gastric mucosal injury as determined by the degree of lymphocyte and neutrophil infiltration. Therefore, in this experimental model, H. pylori-associated gastritis could be successfully treated by orally administered IgY-Hp. The immunological activity of IgY-Hp stayed active at 60 degrees C for 10 min, suggesting that pasteurization can be applied to sterilize the product. Fortification of food products with this immunoglobulin would significantly decrease the H. pylori infection. In conclusion, the IgY-Hp obtained from hens immunized by H. pylori could provide a novel alternative approach to treatment of H. pylori infection.