Chicken egg yolk antibodies (IgY) as non-antibiotic production enhancers for use in swine production: a review

Long-Term Oral Administration of Hyperimmune Egg-Based IgY-Rich Formulations Induces Mucosal Immune Response and Systemic Increases of Cytokines Involved in Th2- and Th17-Type Immune Responses in C57BL/6 Mice

Three hyperimmune egg-based formulations rich in immunoglobulin Y (IgY) were orally administered (daily, for up to 90 days) to C57BL/6 mice that were not microbially challenged. The serum levels of 32 cytokines were quantified every 30 days. Histopathology, hematology, and serum biochemistry investigations were also performed. As a sign of increased immune activity, lymphohistiocytic infiltrates were detected in the digestive tract and the liver after 30, 60, and 90 days of treatment. These infiltrates were also present in the lungs after 30 and 60 days, but not at 90 days. Blood analysis indicated systemic inflammation after 30 days of treatment: increases in pro-inflammatory cytokines, glycemia, total serum proteins, ALT, and ALP. After 60 and 90 days of treatment, the analyzed blood parameters showed mixed signs of both increased and decreased inflammation. The increased cytokines, which varied with formulation and time of exposure, indicated a combination of mostly Th17- and Th2-type immune responses. As the mice were healthy and housed in standardized sanitary conditions, and were not microbially challenged, the data were consistent with an interaction of IgY with the gut-associated lymphoid tissue as the main mechanism of action. This interaction generated a local immune response, which subsequently induced a systemic response.

Evaluation of specific chicken IgY antibody value developing diagnostic capture antibody ELISA kit against Foot and Mouth disease

The most preferred method for the detection of foot-and-mouth disease (FMD) viral antigen and identification of viral serotype is the enzyme-linked immunosorbent assay (ELISA). Diagnostic tests with high sensitivity are necessary both to distinguish infected vaccinated animals and execute disease control programs for the identification of the carrier animals. The current strategies for the detection of FMD virus are mainly based on the capture antibody (sandwich) ELISA test. The usage of laying pullets as an animal bioreactor for the production of specific egg yolk antibodies (IgY) has increased in recent years due to its high yield, affinity, low price, and quick production turnover. The present study aimed to produce a concentrated and purified IgY polyclonal antibody to design a capture antibody ELISA kit against the FMD virus (FMDV) serotype A. At first, laying hens were immunized with inactivated FMDV serotype virus, and then, on days 14, 21, and 28 following vaccination, the eggs and sera were collected. Afterward, the IgY polyclonal antibodies were extracted and purified from the chicken egg yolk using a polyethylene glycol 6000-ethanol precipitation procedure. Extracts were filtered, purified by ion exchange chromatography, and dialyzed. The purified IgY concentration, estimated by Bradford assay, confirmed its presence by SDS-PAGE and Western blot and also its specific immune reaction by Ouchterlony double immunodiffusion and Dot blot tests. Moreover, for achieving the optimum concentration of antigen/antibody (sera) in sandwich ELISA, a checkerboard titration test was set up based on indirect ELISA results. Eventually, 119 previously confirmed samples (including 80 positive and 39 negative) by both real-time polymerase chain reaction (quantitative PCR, qPCR) and a commercial ELISA kit were used for evaluation of the sensitivity and accuracy of our developed Capture antibody ELISA kit. In this manner, the sensitivity and specificity of our designed kit were 100% and 98%, respectively. Accordingly, the present developed capture ELISA kit based on IgY had high sensitivity and specificity for FMD virus detection and it could be used in the future for both commercial detecting and serotyping applications.

Use of Immunoglobulin Y Antibodies: Biosensor-based Diagnostic Systems and Prophylactic and Therapeutic Drug Delivery Systems for Viral Respiratory Diseases

Respiratory viruses have caused many pandemics from past to present and are among the top global public health problems due to their rate of spread. The recently experienced COVID-19 pandemic has led to an understanding of the importance of rapid diagnostic tests to prevent epidemics and the difficulties of developing new vaccines. On the other hand, the emergence of resistance to existing antiviral drugs during the treatment process poses a major problem for society and global health systems. Therefore, there is a need for new approaches for the diagnosis, prophylaxis, and treatment of existing or new types of respiratory viruses. Immunoglobulin Y antibodies (IgYs) obtained from the yolk of poultry eggs have significant advantages, such as high production volumes, low production costs, and high selectivity, which enable the development of innovative and strategic products. Especially in diagnosing respiratory viruses, antibody-based biosensors in which these antibodies are integrated have the potential to provide superiority in making rapid and accurate diagnosis as a practical diagnostic tool. This review article aims to provide information on using IgY antibodies in diagnostic, prophylactic, and therapeutic applications for respiratory viruses and to provide a perspective for future innovative applications.

Development and evaluation of polyclonal antibodies based antigen capture ELISA for detection of porcine rotavirus

Rotaviruses are rising as zoonotic viruses worldwide, causing the lethal dehydrating diarrhea in children, piglets, and other livestock of economic importance. A simple, swift, cost-effective, highly specific, and sensitive antigen-capture enzyme-linked immunosorbent assay (AC-ELISA) was developed for detection of porcine rotavirus-A (PoRVA) by employing rabbit (capture antibody) and murine polyclonal antibodies (detector antibody) produced against VP6 of PoRVA (RVA/Pig-tc/CHN/TM-a/2009/G9P23). Reactivity of the both polyclonal antibodies was confirmed by using an indirect ELISA, western-blot analysis and indirect fluorescence assay against rVP6 protein and PoRVA. The detection limit of AC-ELISA was found 50 ng/ml of PoRVA protein. The relative sensitivity and specificity of this in-house AC-ELISA were evaluated for detection of PoRVA from 295 porcine diarrhea samples, and results were compared with that of RT-PCR and TaqMan RT-qPCR. The relative sensitivity and specificity of AC-ELISA compared with those of TaqMan RT-qPCR were found as 94.4 and 99.2%, respectively, with the strong agreement (κ -0.58) between these two techniques. Furthermore, AC-ELISA could not detect any cross-reactivity with porcine epidemic diarrhea virus, transmissible gastro-enteritis virus, pseudo rabies virus and porcine circovirus-2. This in-house AC-ELISA efficiently detected PoRVA from clinical samples, which suggests that this technique can be used for large-scale surveillance and timely detection of rotavirus infection in the porcine farms.

Effects of High-Biotin Sample Interference on Antibody Concentrations in Sandwich Immunoassays

The use of antimicrobial growth promoters (AGPs) is banned because of problems associated with drug residues in animal products and increased bacterial resistance. The immunization of chickens with specific antigens is a promising strategy for generating specific antibodies that can target a wide range of antibiotic-resistant bacteria and can be used as an alternative to antibiotics. Immunoglobulin Y (IgY) antibodies in a polyclonal antibody (pAb) format, when administered orally, modulate the ruminal microbiome and maintain animal health and performance; however, there are concerns pertaining to protein impurities and biotin concentrations in the samples. Signal amplification strategies involving the noncovalent interaction of biotin with streptavidin is extensively used in diagnosis and scientific research, particularly in enzyme-linked immunosorbent assays (ELISAs). However, the high concentrations of biotin in samples, especially in those derived from rich sources such as egg yolk, can pose challenges and potentially harm the accuracy of diagnostic tests and protein concentration measurements. This study aimed to evaluate the influence of biotin on the measurement of IgY in freeze-dried egg yolk samples obtained from immunized laying hens using immunoassays with biotin-avidin/streptavidin. The detection of IgY in yolk samples using ELISA with streptavidin-biotin binding could lead to misdiagnosis due to biotin interference; the level of interference varies with the specific assay conditions and the concentration of biotin in the yolk samples. An ELISA without streptavidin-biotin binding is advisable to avoid interactions between biotin and target proteins, prevent biotin interference with the results, and achieve more reliable and accurate results.

Production of Egg Yolk Antibody (IgY) Against Vibrio Cholerae O1: Protective Effect in Mice

BACKGROUND

Cholera is an acute intestinal infection caused by Vibrio cholera (V. cholera). The development of antibodies against specific V. cholerae may have a therapeutic effect. In the present research, we investigated the protective effect of egg yolk Immunoglobulin (IgY), which was produced by immunizing hens with formaldehyde-killed V. cholerae O1 and subsequently the isolated IgY was orally administrated to the V. cholerae O1 infected mice for evaluation of its immunizing capability.

METHODS

In the current study, hens were immunized three times with formaldehyde-killed V. cholerae O1 (1.5×107 CFU/ml) and an equal volume of adjuvant. The IgY was isolated from egg yolk by polyethylene glycol method. The validity and activity of isolated IgY were confirmed with SDS-PAGE and ELISA methods, respectively. Subsequently IgY was orally administered to suckling mice following challenge with V. cholerae O1. ELISA results showed high antibody titer in the serum and egg yolk. Also, SDS-PAGE analysis showed successful purification of IgY and anti-V. cholerae IgY prevented the death of mice infected with V. cholerae O1. The anti-V. cholera IgY was administered at 2, 4, 6 hr intervals after 3 hr of inoculation of mice with V. cholerae O1.

RESULTS

Results showed that the rate of surviving mice (2 mg/ml of IgY) were 60% after 4 hr and 40% after 6 hr and the rate of surviving mice (5 mg/ml of IgY) was 70% after 4 hr and 60% after 6 hr.

CONCLUSION

The findings suggested the egg yolk-driven IgY as a natural antibacterial protein, could be effective in the prevention and treatment of cholera disease.

IgYs: on her majesty's secret service

There has been an increasing interest in using Immunoglobulin Y (IgY) antibodies as an alternative to "classical" antimicrobials. Unlike traditional antibiotics, they can be utilized on a continual basis without leading to the development of resistance. The veterinary IgY antibody market is growing because of the demand for minimal antibiotic use in animal production. IgY antibodies are not as strong as antibiotics for treating infections, but they work well as preventative agents and are natural, nontoxic, and easy to produce. They can be administered orally and are well tolerated, even by young animals. Unlike antibiotics, oral IgY supplements support the microbiome that plays a vital role in maintaining overall health, including immune system function. IgY formulations can be delivered as egg yolk powder and do not require extensive purification. Lipids in IgY supplements improve antibody stability in the digestive tract. Given this, using IgY antibodies as an alternative to antimicrobials has garnered interest. In this review, we will examine their antibacterial potential.

Can egg yolk antibodies terminate the CSBV infection in apiculture?

Chinese sacbrood virus (CSBV) is the most severe pathogen of Apis cerana, which leads to serious fatal diseases in bee colonies and eventual catastrophe for the Chinese beekeeping industry. Additionally, CSBV can potentially infect Apis mellifera by bridging the species barrier and significantly affect the productivity of the honey industry. Although several approaches, such as feeding royal jelly, traditional Chinese medicine, and double-stranded RNA treatments, have been employed to suppress CSBV infection, their practical applicabilities are constrained due to their poor effectiveness. In recent years, specific egg yolk antibodies (EYA) have been increasingly utilized in passive immunotherapy for infectious diseases without any side effects. According to both laboratory research and practical use, EYA have demonstrated superior protection for bees against CSBV infection. This review provided an in-depth analysis of the issues and drawbacks in this field in addition to provide a thorough summary of current advancements in CSBV studies. Some promising strategies for the synergistic study of EYA against CSBV, including the exploitation of novel antibody drugs, novel TCM monomer/formula determination, and development of nucleotide drugs, are also proposed in this review. Furthermore, the prospects for the future perspectives of EYA research and applications are presented. Collectively, EYA would terminate CSBV infection soon, as well as will provide scientific guidance and references to control and manage other viral infections in apiculture.

Establishment of a reverse transcription recombinase-aided amplification detection method for porcine group a rotavirus

Porcine rotavirus type A (PoRVA) is the main cause of dehydration and diarrhea in piglets, which has a great impact on the development of the pig industry worldwide. A rapid, accurate and sensitive detection method is conducive to the monitoring, control, and removal of PoRVA. In this study, a PoRVA real-time fluorescent reverse transcription recombinase-aided amplification (RT-RAA) assay was developed. Based on the PoRVA VP6 gene, specific primers and probes were designed and synthesized. The sensitivity of RT-RAA and TaqMan probe-based RT-qPCR was 7 copies per reaction and 5 copies per reaction, respectively. The sensitivity of the RT-RAA method was close to TaqMan probe-based RT-qPCR. The detection results of RT-RAA and TaqMan probe-based quantitative real-time RT-PCR methods were completely consistent in 241 clinical samples. Therefore, we successfully established a rapid and specific RT-RAA diagnostic method for PoRVA.

The production and influence of anti-Vibrio parahaemolytics IgY against experimental infection of V. parahaemolyticus in cultured Fenneropenaeus indicus

The increasing number of antibiotic-resistant bacteria emphasizes the need to find alternatives to complement antibiotics. Immunotherapy may also be used as a complementary treatment against pathogens that are difficult to treat with traditional antibiotics. Eggs are normal dietary components and there is practically no risk of toxic side effects of IgY given orally. In the present study, pathogenic Vibrio parahaemolyticus was isolated from infected shrimp and studied their virulence factors including LD₅₀ (by challenging with Fenneropenaeus indicus), proteolytic and hemolytic activities. The edible antibody IgY was raised by injecting the antigen of Extra Cellular Products (ECP) of V. parahaemolyticus to Gallus gallus domesticus during layoff period with and without the herbal immunoadjuvants, Asparagus racemosus and Glycine max (V.p wo: V. parahaemolyticus ECP without adjuvant; V.p A: V. parahaemolyticus ECP with A. racemosus and V.p G: V. parahaemolyticus ECP with G. max). Eggs were collected after five weeks of immunization and anti- V. parahaemolyticus IgY was extracted and purified. Physicochemical properties of the immunized Chickens' serum and anti- V. parahaemolyticus IgY's cross reactivity, growth inhibition assay, single radial immunodiffusion assay and bacterial agglutination were studied. The results revealed that, the serum protein parameters were significantly (P ≤ 0.001) increased in experimental groups from control group. The antibody raised with immunoadjuvants had significantly (P ≤ 0.001) higher cross reactivity, growth inhibition, single radial immunoassay and bacterial agglutination when compared with and without immunoadjuvant and control groups. Further the control and experimental anti-V. parahaemolytics IgY coated artificial diets were fed to F. indicus for 60 days. After 30 and 60 dpv (days of post vaccination), shrimps from each groups were challenged with virulent V. parahaemolyticus and studied the survival, haematological and immunological parameters. The IgY coated diets (V. p A and V.p G) fed shrimps had decreased cumulative mortality, significantly (P ≤ 0.001) improved coagulase activity, total haemocyte count and oxyhaemocyanin. The immunological parameters such as prophenoloxidase, intracellular anion production, lysozyme production and phagocytosis also improved significantly (P ≤ 0.001) in IgY treated shrimps.

Potential Substitutes of Antibiotics for Swine and Poultry Production

Early of the last century, it was detected that antibiotics added to the animal feeds at low doses and for a long time can improve technical performances such as average daily gain and gain-to-feed ratio. Since then, the antibiotics have been used worldwide as feed additives for many decades. At the end of the twentieth century, the consequences of the uses of antibiotics in animal feeds as growth promoters were informed. Since then, many research studies have been done to find other solutions to replace partly or fully to antibiotic as growth promoters (AGPs). Many achievements in finding alternatives to AGPs in which probiotics and direct-fed microorganism, prebiotics, organic acids and their salts, feed enzymes, bacteriophages, herbs, spices, and other plant extractives (phytogenics), mineral and essential oils are included.

Effect of red ginger powder (Zingiber officinale var. rubrum) as a feed additive for starter and finisher broiler chicken to increase immunoglobulin A and immunoglobulin Y expression and to prevent intestinal injury due to Salmonella enteritidis infection

Background and Aim:

Salmonellosis is an infectious disease that often occurs in chickens and is caused by Salmonella enteritidis. The use of antibiotics to prevent this disease can result in the development of resistance in pathogenic bacteria, in addition to the presence of antibiotic residues in consumed carcasses. Red ginger (Zingiber officinale var. rubrum) has active compounds that potentially act as immunomodulators which increase specific and non-specific immune responses through the induction of cytokine production. This study was conducted to determine the effects of red ginger powder mixed in feed for starter and finisher broiler chickens, based on the evaluation of the expression of immunoglobulin A (IgA), histopathologic description of the ileum and cecum, IgA, and immunoglobulin Y (IgY) expression in the spleen, and the isolation count of S. enteritidis in fresh fecal samples.

Materials and Methods:

A total of 100 starter and 100 finisher Cobb broiler chickens were divided into four groups, designated as T0, T1, T2, and T3, respectively: Group T0 was fed commercial feed with no added 2% red ginger powder or S. enteritidis induction, and served as a negative control; Group T1 was inoculated with a 0.25 mL S. enteritidis oral induction (1 × 10⁷ colony-forming unit [CFU] [0.5 McFarland standard]), and served as a positive control; Group T2 was fed with feed containing 2% red ginger powder; while Group T3 was fed with feed containing 2% red ginger powder and was orally inoculated with S. enteritidis with a dose similar to T1. The normal feed was given on the 1^st–7^th days. The mixture of 2% red ginger powder was given on the 7^th–15^th days. The S. enteritidis was induced on the 15^th day (1 × 10⁷ CFU). Necropsy was performed on the 16^th day and tissues were fixed in 10% formalin and routinely processed for histopathologic and immunohistochemical analyses. The data were analyzed using a one-way analysis of variance test, Tukey’s analysis, and the Mann–Whitney U non-parametric statistical analysis test.

Results:

The 2% red ginger powder was found to significantly (p < 0.05) increase IgA expression and additionally decrease tissue damage in the cecum and ileum. It also increased IgA and IgY expression in the spleen. In addition, a decrease was observed in the S. enteritidis number isolated from finisher fresh feces, but none was found in the isolated starter fresh feces.

Conclusion:

These findings indicate that the addition of red ginger powder to chicken feed is a potential natural immunomodulator against S. enteritidis infection.

Egg Allergy in Children and Weaning Diet

Eggs are a fundamental food in the human diet, and together with cow’s milk, they are the most common food allergen. This work highlights the main nutritional characteristics of eggs to show how their absence from a child’s diet can constitute a serious deficiency. We then analyze the risk factors that facilitate the onset of egg allergy. The third part of the paper reports possible interventions to lower the appearance of food allergy that have been occurred in trials. The last part of the paper is a synthesis of this research study that has been taken from several of the latest guidelines or from position papers.

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

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

Advances in Chicken IgY-Based Immunoassays for the Detection of Chemical and Biological Hazards in Food Samples

As antibodies are the main biological binder for hazards in food samples, their performance directly determines the sensitivity, specificity, and reproducibility of the developed immunoassay. The overwhelmingly used mammalian-derived antibodies usually suffer from complicated preparation, high cost, frequent bleeding of animals, and sometimes low titer and affinity. Chicken yolk antibody (IgY) has recently attracted considerable attention in the bioanalytical field owing to its advantages in productivity, animal welfare, comparable affinity, and high specificity. However, a broad understanding of the application of IgY-based immunoassay for the detection of chemical and biological hazards in food samples remains limited. Here, we briefly summarized the diversity, structure, and production of IgY including polyclonal and monoclonal formats. Then, a comprehensive overview of the principles, designs, and applications of IgY-based immunoassays for these hazards was reviewed and discussed, including food-borne pathogens, food allergens, veterinary drugs, pesticides, toxins, endocrine disrupting chemicals, etc. Thus, the trend of IgY-based immunoassays is expected, and more IgY types, higher sensitivity, and diversification of recognition-to-signal manners are necessary in the future.

Human allergy to cats: A review for veterinarians on prevalence, causes, symptoms and control

PRACTICAL RELEVANCE

Human allergy to cats affects a substantial and growing proportion of the global population, and cat allergy is regarded as the third most common cause of human respiratory allergies, and the second most common indoor cause. Veterinarians will frequently encounter owners who are cat-allergic, and having an understanding of this disease and the methods available to help control the allergy will assist them in giving appropriate advice, alongside human healthcare professionals.

AIM

The aim of this review is to summarise currently available data on the prevalence, causes, symptoms and control of human allergy to cats. In terms of managing cat allergy, the emphasis is on reviewing current and emerging modalities to reduce environmental exposure to cat allergens rather than on pharmacotherapy or immunotherapy, as it is in these areas in particular that the veterinarian may be able to offer help and advice to complement that of human healthcare professionals.

EVIDENCE BASE

The information in this review is drawn from the current and historical literature on human allergy to cats, and approaches to reduce exposure to cat allergens and manage symptoms of cat allergy.

Effects of Dietary Probiotic (Bacillus subtilis) Supplementation on Carcass Traits, Meat Quality, Amino Acid, and Fatty Acid Profile of Broiler Chickens

The aim of the present study was to evaluate the effects of dietary supplementation with or without Bacillus subtilis (B. subtilis) on carcass traits, meat quality, amino acids, and fatty acids of broiler chickens. In total, 160 1-day-old Arbor Acres male broiler chicks were divided into two groups with eight replicates of 10 chicks each. Chickens received basal diets without (CN group) or with 500 mg/kg B. subtilis (BS group) for 42 days. Eight chickens from each group were slaughtered at the end of the trial, and carcass traits, meat quality, chemical composition, amino acid, and fatty acid profile of meat were measured. The results showed that the breast muscle (%) was higher in BS than in CN (p < 0.05), while abdominal fat decreased (p < 0.05). The pH_24h of thigh muscle was increased (p < 0.05) when supplemented with BS; however, drip loss, cooking loss of breast muscle, and shear force of thigh muscle decreased (p < 0.05). Lysine (Lys), methionine (Met), glutamic acid (Glu), and total essential amino acid (EAA) in breast muscle and Glu in thigh muscle were greater in BS than in CN (p < 0.05). C16:1, C18:1n9c, and MUFA in breast muscle and thigh muscle were greater in BS than in CN (p < 0.05). In conclusion, dietary supplementation with B. subtilis could improve the carcass traits and meat quality of broilers, which is beneficial for the consumers due to the improved fatty acid profile and amino acid composition.

Potential Therapeutic Effects of Egg Yolk Antibody (IgY) in Helicobacter pylori Infections─A Review

Currently, the infection with Helicobacter pylori affects about half of the world's population, and the most common therapy to treat H. pylori is the first line clarithromycin-based triple therapy or the quadruple therapy. However, drug resistance, eradication in a low level, high rate of reinfection, and gastrointestinal side effects among the causative organisms for H. pylori infection pose a critical challenge to the global health care community. Therefore, new approaches to treat H. pylori infections are urgently needed. Chicken egg yolk constituting a source of immunoglobulin Y (IgY) has attracted noticeable attention for its advantages of cost-effective extraction, minimization of animal harm and suffering, and induction of no specific resistance and is, therefore, being regarded as an alternative therapy for H. pylori infection. This review is intended to summarize various H. pylori antigens for IgY preparation in terms of their application, mechanism, and limitations.

Tecnología IgY: Estrategia en el tratamiento de enfermedades infecciosas humanas

La aparición de microorganismos resistentes a antibióticos, el descubrimiento de nuevos agentes patógenos con potencial pandémico y el aumento de una población inmunocomprometida han dejado casi obsoleta la terapia antimicrobiana, terapia comúnmente usada para tratar enfermedades infecciosas. Por otro lado, las investigaciones acerca del uso del anticuerpo IgY para desarrollar inmunidad pasiva han demostrado el potencial que tiene la tecnología IgY para tratar enfermedades infecciosas víricas y bacterianas. Donde los anticuerpos IgY de aves se destacan por su alta especificidad, rendimiento y escalabilidad de producción a menor costo, con relación a los anticuerpos IgG de mamíferos. El objetivo de esta revisión es determinar la importancia del uso de los anticuerpos IgY como tratamiento terapéutico y profiláctico frente a los patógenos causantes de infecciones virales y bacterianas en humanos, mediante la recopilación de ensayos clínicos, productos comerciales y patentes registradas en el período de 2010-2021. Finalmente, con este estudio se estableció que la tecnología IgY es una herramienta biotecnológica versátil y eficaz para tratar y prevenir enfermedades infecciosas, al reducir los síntomas y la carga del patógeno.

Inhalation monoclonal antibody therapy: a new way to treat and manage respiratory infections

The route of administration of a therapeutic agent has a substantial impact on its success. Therapeutic antibodies are usually administered systemically, either directly by intravenous route, or indirectly by intramuscular or subcutaneous injection. However, treatment of diseases contained within a specific tissue necessitates a better alternate route of administration for targeting localised infections. Inhalation is a promising non-invasive strategy for antibody delivery to treat respiratory maladies because it provides higher concentrations of antibody in the respiratory airways overcoming the constraints of entry through systemic circulation and uncertainity in the amount reaching the target tissue. The nasal drug delivery route is one of the extensively researched modes of administration, and nasal sprays for molecular drugs are deemed successful and are presently commercially marketed. This review highlights the current state and future prospects of inhaled therapies, with an emphasis on the use of monoclonal antibodies for the treatment of respiratory infections, as well as an overview of their importance, practical challenges, and clinical trial outcomes.Key points• Immunologic strategies for preventing mucosal transmission of respiratory pathogens.• Mucosal-mediated immunoprophylaxis could play a major role in COVID-19 prevention.• Applications of monoclonal antibodies in passive immunisation.

Immunotherapeutic Efficacy of IgY Antibodies Targeting the Full-Length Spike Protein in an Animal Model of Middle East Respiratory Syndrome Coronavirus Infection

Identified in 2012, the Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe and often fatal acute respiratory illness in humans. No approved prophylactic or therapeutic interventions are currently available. In this study, we developed chicken egg yolk antibodies (IgY Abs) specific to the MERS-CoV spike (S) protein and evaluated their neutralizing efficiency against MERS-CoV infection. S-specific IgY Abs were produced by injecting chickens with the purified recombinant S protein of MERS-CoV at a high titer (4.4 mg/mL per egg yolk) at week 7 post immunization. Western blotting and immune-dot blot assays demonstrated specific binding to the MERS-CoV S protein. In vitro neutralization of the generated IgY Abs against MERS-CoV was evaluated and showed a 50% neutralizing concentration of 51.42 μg/mL. In vivo testing using a human-transgenic mouse model showed a reduction of viral antigen positive cells in treated mice, compared to the adjuvant-only controls. Moreover, the lung cells of the treated mice showed significantly reduced inflammation, compared to the controls. Our results show efficient neutralization of MERS-CoV infection both in vitro and in vivo using S-specific IgY Abs. Clinical trials are needed to evaluate the efficiency of the IgY Abs in camels and humans.

Immunotherapeutic Efficacy of IgY Antibodies Targeting the Full-Length Spike Protein in an Animal Model of Middle East Respiratory Syndrome Coronavirus Infection

Identified in 2012, the Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe and often fatal acute respiratory illness in humans. No approved prophylactic or therapeutic interventions are currently available. In this study, we developed chicken egg yolk antibodies (IgY Abs) specific to the MERS-CoV spike (S) protein and evaluated their neutralizing efficiency against MERS-CoV infection. S-specific IgY Abs were produced by injecting chickens with the purified recombinant S protein of MERS-CoV at a high titer (4.4 mg/mL per egg yolk) at week 7 post immunization. Western blotting and immune-dot blot assays demonstrated specific binding to the MERS-CoV S protein. In vitro neutralization of the generated IgY Abs against MERS-CoV was evaluated and showed a 50% neutralizing concentration of 51.42 μg/mL. In vivo testing using a human-transgenic mouse model showed a reduction of viral antigen positive cells in treated mice, compared to the adjuvant-only controls. Moreover, the lung cells of the treated mice showed significantly reduced inflammation, compared to the controls. Our results show efficient neutralization of MERS-CoV infection both in vitro and in vivo using S-specific IgY Abs. Clinical trials are needed to evaluate the efficiency of the IgY Abs in camels and humans.

Effect of Replacing in-Feed Antibiotic Growth Promoters with a Combination of Egg Immunoglobulins and Phytomolecules on the Performance, Serum Immunity, and Intestinal Health of Weaned Pigs Challenged with Escherichia coli K88

Simple Summary

Post-weaning diarrhea (PWD) in pigs caused by Escherichia coli (E. coli) is a global problem which results in substantial economic losses, due to decreased performance and a high incidence of mortality and morbidity. Due to the banning of antibiotic growth promoters (AGPs) by many countries, it would be valuable to find environmentally friendly and non-antibiotic alternatives to AGPs and to evaluate their effectiveness. Both immunoglobulins and phytomolecules are separately reported as benefiting animal growth, but the efficiency of combinations of immunoglobulins and phytomolecules as AGP alternatives is largely unknown. In this study, the results showed that a mixture of immunoglobulin and phytomolecule administration had positive effects on feed efficiency, diarrhea reduction, intestinal morphology, and coliform control. Combinations of immunoglobulins and phytomolecules can be used as a potential alternative to AGPs in weanling piglets.

Abstract

The study was conducted to investigate the effects of replacing antibiotic growth promoters (AGPs) with an egg immunoglobulin (IgY) combined with phytomolecules (PM) on the growth rate, serum immunity, and intestinal health of weaned pigs challenged with Escherichia coli K88 (E. coli K88). A total of 192 piglets were weaned at 28 days old with an average weight of 7.29 (± 0.04) kg. They were randomly divided into four treatments containing eight replicates with six piglets per replicate. The treatment groups were NC and PC fed a basal diet, AGP fed a basal diet supplemented with 75 mg/kg chlortetracycline, 50 mg/kg oxytetracycline calcium, and 40 mg/kg zinc bacitracin, IPM fed a basal diet supplemented with IgY at dose of 2.5 g/kg and 1.0 g/kg and PM at dose of 300 mg/kg and 150 mg/kg during days 1 to 17 and 18 to 42, respectively. On days 7 to 9 of the experiment, piglets in the PC, AGP, and IPM groups were orally challenged with 20 mL E. coli K88 (10⁹ CFU/mL), while piglets in the NC group were challenged with 20 mL medium without E. coli K88. The E. coli K88 challenge model was successful as the incidence of post-weaning diarrhea (PWD) of piglets challenged with E. coli K88 was significantly higher than that of those unchallenged piglets during the challenge time (days 7 to 9) and days 1 to 7 of post-challenge (p < 0.05). A diet with combinations of IgY and PM and AGPs significantly decreased the incidence of PWD during the challenge time and days 1 to 7 of post-challenge (p < 0.05) compared to the PC group and significantly improved the ratio of feed to weight gain (F:G) during days 1 to 17 of the experiment compared to the NC and PC groups (p < 0.05). In comparison with the PC group, piglets in the IPM group had significantly higher serum levels of IgA, IgG, and IgM (p < 0.05), but lower serum IL-1β on day 17 of experiement (p < 0.05). Besides, diet supplementation with AGP significantly decreased serum IL-1β, IL-6, and TNF-α on days 17 and 42 (p < 0.05) with comparison to the PC group. Piglets in the IPM group showed a significantly lower level of fecal coliforms (p < 0.05), but a higher villus height of jejunum and ileum and higher ratio of villus height to crypt depth of duodenum and jejunum (p < 0.05) than those piglets in the PC group. In summary, diet supplementation with a mixture of IgY and PM decreased the incidence of PWD and coliforms, increased feed conversion ratio, and improved intestinal histology and immune function.

Chicken Egg Yolk Antibody (IgY) Protects Mice Against Enterotoxigenic Escherichia coli Infection Through Improving Intestinal Health and Immune Response

Chicken egg yolk antibody (IgY), considered as a potential substitute for antibiotics, has been used for preventing pathogens infection in food, human and animals. This study investigated effects of IgY on growth, adhesion inhibitory and morphology of enterotoxigenic Escherichia coli (ETEC) K88 in vitro, and evaluated the protective effects of IgY on intestinal health and immune response of mice infected with ETEC in vivo. Sixty pathogen-free C57BL/6J (4-6 weeks of age) mice were divided into six treatments: control (neither IgY nor ETEC infection), ETEC infection, ETEC-infected mice treated with 250 μL of high-dose (32 mg/mL), medium-dose (16 mg/mL) or low-dose (8 mg/mL) anti-ETEC IgY, or ETEC-infected mice treated with 250 μL of non-specific IgY (16 mg/mL). Anti-ETEC IgY inhibited ETEC growth, reduced adherence of ETEC to intestinal epithelial cells J2 and damaged the morphology and integrity of ETEC cell. Oral administration of anti-ETEC IgY effectively ameliorated ETEC-induced clinical signs, reduced ETEC colonization and intestinal permeability, alleviated inflammatory response through reducing the production and expression of proinflammatory cytokines, improved intestinal morphology, and inhibited excessive activation of the mucosal immune response of challenged mice. The overall protective effects of high-dose and medium-dose anti-ETEC IgY against ETEC infection were more effective. These results suggest that anti-ETEC IgY may function as a promising novel prophylactic agent against enteric pathogens infection.

Towards Zero Zinc Oxide: Feeding Strategies to Manage Post-Weaning Diarrhea in Piglets

Simple Summary

Zinc oxide (ZnO) supplementation at pharmacological doses in post-weaning piglets is a consolidated practice that allows efficient control of post-weaning diarrhea (PWD), a condition exacerbated by Escherichia coli F4 (K88) infections. Far from being completely elucidated, the multifactorial ZnO mechanism of action is in all likelihood exerted at the gastrointestinal level. However, increasing environmental concerns are arising from prolonged ZnO use. This article reviews the utilization of ZnO in piglets, the biological rationale behind its powerful activity, and the emerging threats that are leading towards a significant reduction in its use. Finally, a wide analysis of the strengths and weaknesses of innovative alternative strategies to manage PWD at the nutritional level is given.

Abstract

Zinc oxide (ZnO) at pharmacological doses is extensively employed in the pig industry as an effective tool to manage post-weaning diarrhea (PWD), a condition that causes huge economic losses because of its impact on the most pivotal phase of a piglet’s production cycle. In a multifactorial way, ZnO exerts a variety of positive effects along the entire gastrointestinal tract by targeting intestinal architecture, digestive secretions, antioxidant systems, and immune cells. ZnO also has a moderate antibacterial effect against Escherichia coli F4 (K88), the main causative agent of PWD. However, the environmental impact of ZnO and new emerging threats are posing serious questions to the sustainability of its extensive utilization. To work towards a future free from pharmacological ZnO, novel nutritional approaches are necessary, and many strategies have been investigated. This review article provides a comprehensive framework for ZnO utilization and its broad mode of action. Moreover, all the risks related to pharmacological ZnO levels are presented; we focus on European institutions’ decisions subsequently. The identification of a novel, complete solution against PWD should be accompanied by the adoption of holistic strategies, thereby combining good management practices to feeding approaches capable of mitigating Escherichia coli F4 (K88) infections and/or lowering ZnO utilization. Promising results can be obtained by adjusting diet composition or employing organic acids, natural identical compounds, polyphenol-rich extracts, prebiotics, and probiotics.

Immunosecurity: immunomodulants enhance immune responses in chickens

The global population has increased with swift urbanization in developing countries, and it is likely to result in a high demand for animal-derived protein-rich foods. Animal farming has been constantly affected by various stressful conditions, which can be categorized into physical, environmental, nutritional, and biological factors. Such conditions could be exacerbated by banning on the use of antibiotics as a growth promoter together with a pandemic situation including, but not limited to, African swine fever, avian influenza, and foot-and-mouth disease. To alleviate these pervasive tension, various immunomodulants have been suggested as alternatives for antibiotics. Various studies have investigated how stressors (i.e., imbalanced nutrition, dysbiosis, and disease) could negatively affect nutritional physiology in chickens. Importantly, the immune system is critical for host protective activity against pathogens, but at the same time excessive immune responses negatively affect its productivity. Yet, comprehensive review articles addressing the impact of such stress factors on the immune system of chickens are scarce. In this review, we categorize these stressors and their effects on the immune system of chickens and attempt to provide immunomodulants which can be a solution to the aforementioned problems facing the chicken industry.

Effects of α-glyceryl monolaurate on growth, immune function, volatile fatty acids, and gut microbiota in broiler chickens

This study was conducted to determine the effects of dietary addition of α-glyceryl monolaurate (α-GML) on growth performance, immune function, volatile fatty acids production and cecal microbiota in broiler chickens. A total of 480 1-day-old yellow-feathered broilers were randomly assigned in equal numbers to 4 dietary treatments: basal diet (NCO) or supplementations with 30 mg/kg bacitracin (ANT), 500 mg/kg α-GML, or 1,000 mg/kg α-GML (GML2). And, each treatment contained 8 replicates with 15 chickens per replicate. After supplementation with α-GML, the total BW gain and average daily weight gain of broilers increased significantly (P < 0.05) compared with the broilers on the NCO diet. Moreover, compared with the NCO group, higher levels of immune globulin M and immune globulin Y were observed in both GML groups and the ANT group. Concentrations of acetate, propionate, butyrate, valerate, and isovalerate in GML2 were significantly higher (P < 0.05) than those in the NCO group on day 28. However, acetate, propionate, valerate, and isovalerate concentrations were reduced to significantly (P < 0.05) lower than those in the NCO group on day 56. The abundance and diversity of microbiota were found to be improved in broilers that were supplemented with GML, using operational taxonomic unit and diversity analyses. Furthermore, the GML treatments increased favorable microbiota, particularly acid-producing bacteria, on day 28 and, also, reduced opportunistic pathogens, such as Alistipes tidjanibacter and Bacteroides dorei by day 56. These results suggest that α-GML supplementation modulates cecal microbiota and broiler immunity and improves volatile fatty acid levels during the early growth stages of broilers.

Anti-S1 MERS-COV IgY Specific Antibodies Decreases Lung Inflammation and Viral Antigen Positive Cells in the Human Transgenic Mouse Model

The Middle East respiratory syndrome coronavirus (MERS-CoV) was identified in 2012 and causes severe and often fatal acute respiratory illness in humans. No approved prophylactic and therapeutic interventions are currently available. In this study, we have developed egg yolk antibodies (immunoglobulin Y (IgY)) specific for MERS-CoV spike protein (S1) in order to evaluate their neutralizing efficiency against MERS-CoV infection. S1-specific immunoglobulins were produced by injecting chickens with purified recombinant S1 protein of MERS-CoV at a high titer (5.7 mg/mL egg yolk) at week 7 post immunization. Western blotting and immune-dot blot assays demonstrated that the IgY antibody specifically bound to the MERS-CoV S1 protein. Anti-S1 antibodies were also able to recognize MERS-COV inside cells, as demonstrated by an immunofluorescence assay. Plaque reduction and microneutralization assays showed the neutralization of MERS-COV in Vero cells by anti-S1 IgY antibodies and non-significantly reduced virus titers in the lungs of MERS-CoV-infected mice during early infection, with a nonsignificant decrease in weight loss. However, a statistically significant (p = 0.0196) quantitative reduction in viral antigen expression and marked reduction in inflammation were observed in lung tissue. Collectively, our data suggest that the anti-MERS-CoV S1 IgY could serve as a potential candidate for the passive treatment of MERS-CoV infection.

Anti-S1 MERS-COV IgY Specific Antibodies Decreases Lung Inflammation and Viral Antigen Positive Cells in the Human Transgenic Mouse Model

The Middle East respiratory syndrome coronavirus (MERS-CoV) was identified in 2012 and causes severe and often fatal acute respiratory illness in humans. No approved prophylactic and therapeutic interventions are currently available. In this study, we have developed egg yolk antibodies (immunoglobulin Y (IgY)) specific for MERS-CoV spike protein (S1) in order to evaluate their neutralizing efficiency against MERS-CoV infection. S1-specific immunoglobulins were produced by injecting chickens with purified recombinant S1 protein of MERS-CoV at a high titer (5.7 mg/mL egg yolk) at week 7 post immunization. Western blotting and immune-dot blot assays demonstrated that the IgY antibody specifically bound to the MERS-CoV S1 protein. Anti-S1 antibodies were also able to recognize MERS-COV inside cells, as demonstrated by an immunofluorescence assay. Plaque reduction and microneutralization assays showed the neutralization of MERS-COV in Vero cells by anti-S1 IgY antibodies and non-significantly reduced virus titers in the lungs of MERS-CoV-infected mice during early infection, with a nonsignificant decrease in weight loss. However, a statistically significant (p = 0.0196) quantitative reduction in viral antigen expression and marked reduction in inflammation were observed in lung tissue. Collectively, our data suggest that the anti-MERS-CoV S1 IgY could serve as a potential candidate for the passive treatment of MERS-CoV infection.

The impact of porcine spray-dried plasma protein and dried egg protein harvested from hyper-immunized hens, provided in the presence or absence of subtherapeutic levels of antibiotics in the feed, on growth and indicators of intestinal function and physiology of nursery pigs

The objective of this experiment was to compare the effects of spray-dried plasma protein (SDPP) and dried egg protein (DEP), without (AB-) or with (AB+) in-feed antibiotics, on growth performance and markers of intestinal health in nursery pigs raised in commercial conditions. This 42-d experiment utilized 1,230 pigs (4.93 ± 0.04 kg body weight; approximately 15-18 d of age). Pigs were randomly assigned to one of six dietary treatments that were arranged as a 2 × 3 factorial of in-feed antibiotics (AB- vs. AB+) and a specialty protein additive (none [CON], porcine SDPP, or DEP). Diets were fed in four phases with phases 3 and 4 as a common diet across all treatments. Specialty protein additives were fed in phases 1 (0-13 d; 3% SDPP, and 0.20% DEP) and 2 (13-26 d; 2% SDPP, and 0.10% DEP). Antibiotics were fed in phases 1-3 (662 mg chlortetracycline [CTC]/kg, 28 mg carbadox/kg, and 441 mg CTC/kg, respectively). Ileal tissue and blood samples were collected from 48 pigs (8 per treatment) on d 20. Data were analyzed using PROC MIXED of SAS (9.4) with pen as the experimental unit; protein additives, antibiotics, and their interaction were fixed effects and block was a random effect. The pigs experienced naturally occurring health challenges in weeks 2 and 4. In the AB- diets, SDPP and DEP increased average daily gain (ADG; P = 0.036) and average daily feed intake (ADFI; P = 0.040) compared to CON; in the AB+ diets, neither SDPP nor DEP increased ADG or ADFI compared to CON but SDPP did increase these parameters over DEP. The SDPP and DEP diets decreased the number of individual medical treatments compared to CON (P = 0.001). The AB+ increased ileal mucosal interleukin (IL)-1 receptor antagonist (P = 0.017). Feeding DEP reduced the concentration of mucosal IL-1β compared to CON, but not SDPP (P = 0.022). There was a trend for SDPP and DEP to increase villus height:crypt depth compared to CON (P = 0.066). Neither antibiotics or protein additive affected serum malondialdehyde concentration or ileal mRNA abundance of claudin-3 or 4, occludin, or zonula occludens-1 (P > 0.10). In conclusion, SDPP and DEP improved growth performance of weaned pigs in the absence of antibiotics but neither improved growth compared to CON when feeding standard antibiotic levels. The specialty proteins had a positive effect on health; specialty proteins and antibiotics were able to modulate some markers of intestinal inflammation and morphology.

Immunotherapy with IgY Antibodies toward Outer Membrane Protein F Protects Burned Mice against Pseudomonas aeruginosa Infection

Burn patients with multidrug-resistant Pseudomonas aeruginosa infections commonly suffer from high morbidity and mortality, which present a major challenge to healthcare systems throughout the world. Outer membrane protein F (OprF), as a main outer membrane porin, is required for full virulence expression of P. aeruginosa. The aim of this study was to evaluate the protective efficacy of egg yolk-specific antibody (IgY) raised against recombinant OprF (r-OprF) protein in a murine burn model of infection. The hens were immunized with r-OprF, and anti-r-OprF IgY was purified using salt precipitation. Groups of mice were injected with different regimens of anti-OprF IgY or control IgY (C-IgY). Infections were caused by subcutaneous injection of P. aeruginosa strain PAO1 at the burn site. Mice were monitored for mortality for 5 days. The functional activity of anti-OprF IgY was determined by in vitro invasion assays. Immunotherapy with anti-OprF IgY resulted in a significant improvement in the survival of mice infected by P. aeruginosa from 25% to 87.5% compared with the C-IgY and PBS. The anti-OprF IgY decreased the invasion of P. aeruginosa PAO1 into the A549. Passive immunization with anti-OprF IgY led to an efficacious protection against P. aeruginosa burn infection in the burn model.

IgY - turning the page toward passive immunization in COVID-19 infection (Review)

The world is facing one of the major outbreaks of viral infection of the modern history, however, as vaccine development workflow is still tedious and can not control the infection spreading, researchers are turning to passive immunization as a good and quick alternative to treat and contain the spreading. Within passive immunization domain, raising specific immunoglobulin (Ig)Y against acute respiratory tract infection has been developing for more than 20 years. Far from being an obsolete chapter we will revise the IgY-technology as a new frontier for research and clinic. A wide range of IgY applications has been effectively confirmed in both human and animal health. The molecular particularities of IgY give them functional advantages recommending them as good candidates in this endeavor. Obtaining specific IgY is sustained by reliable and nature friendly methodology as an alternative for mammalian antibodies. The aria of application is continuously enlarging from bacterial and viral infections to tumor biology. Specific anti-viral IgY were previously tested in several designs, thus its worth pointing out that in the actual COVID-19 pandemic context, respiratory infections need an enlarged arsenal of therapeutic approaches and clearly the roles of IgY should be exploited in depth.

Use of polyclonal IgY antibodies to detect serum immune complexes in patients with active hookworm infection

Definitive diagnosis of hookworm infection is usually based on the microscopic detection of eggs in a stool sample; however, several cases display a low or irregular egg output. Serodiagnosis can be a useful tool to identify these cases, but conventional tests do not differentiate past from active infections. The aim of this study was to obtain and apply egg yolk polyclonal immunoglobulin (IgY) antibodies to detect immune complexes (ICs) in serum samples from patients infected with hookworm. Hens were immunized with Ancylostoma ceylanicum saline extract, their eggs were collected and then IgY antibodies were extracted and purified. Antibody purity was tested by 12% sodium dodecyl sulphate polyacrylamide gel electrophoresis and specificity was assessed by immunoblotting and immunofluorescence. IgY production was evaluated by kinetics enzyme-linked immunosorbent assay (ELISA). Sandwich ELISA tested the ability of IgY to detect ICs in serum samples, from which diagnostic parameters were calculated. Antibody responses increased steadily from day 7 to 42. In the immunoblotting assay, IgY recognized two protein complexes. The immunofluorescence assay showed no staining in control samples. The sandwich ELISA presented a very high diagnostic value, with a sensitivity of 90% and a specificity of 86.7%. Our pioneer strategy highlights the potential use of egg yolk IgY as a diagnostic test to detect active hookworm infection.

Anti-PcrV IgY antibodies protect against Pseudomonas aeruginosa infection in both acute pneumonia and burn wound models

Pseudomonas aeruginosa is a common nosocomial pathogen in burn patients, and rapidly acquires antibiotic resistance; thus, developing an effective therapeutic approach is the most promising strategy for combating infection. Type III secretion system (T3SS) translocates bacterial toxins into the cytosol of the targeted eukaryotic cells, which plays important roles in the virulence of P. aeruginosa infections in both acute pneumonia and burn wound models. The PcrV protein, a T3SS translocating protein, is required for T3SS function and is a well-validated target in animal models of immunoprophylactic strategies targeting P. aeruginosa. In the present study, we evaluated the protective efficacy of chicken egg yolk antibodies (IgY) raised against recombinant PcrV (r-PcrV) in both acute pneumonia and burn wound models. R-PcrV protein was generated by expressing the pcrV gene (cloned in pET-28a vector) in E. coli BL-21. Anti-PcrV IgY was obtained by immunization of hen. Anti-PcrV IgY induced greater protection in P. aeruginosamurine acute pneumonia and burn wound models than control IgY (C-IgY) and PBS groups. Anti-PcrV IgY improved opsonophagocytic killing and inhibition of bacterial invasion of host cells. Taken together, our data provide evidence that anti-PcrV IgY can be a promising therapeutic candidate for combating P. aeruginosa infections.

Effect of chicken egg yolk immunoglobulins on serum biochemical profiles and intestinal bacterial populations in early-weaned piglets

This study was conducted to test the hypothesis that dietary supplementation with anti-E. coli, chicken egg yolk immunoglobulins (IgY), may affect early weaned piglet (EWP) intestinal functions and enteric micro-organisms. One hundred and forty-eight ([Landrace × Yorkshire] × Duroc) piglets, weaned at age day 21, were randomly assigned to receive one of three diets for 14 days. Treatment group one (control group) was fed the base diet. Treatment group two (antibiotics group) was fed the base diet which was supplemented with 100 ppm colistin sulphate and 15 ppm enramycin; treatment group three (IgY group) was fed the base diet which was supplemented with 500 mg/kg anti-E. coli IgY. The study evaluated the effects on EWPs of IgY on growth, serum biochemical, inflammatory profiles and also digestion content intestinal bacterial populations. Results showed no significant difference in diarrhoea rates between IgY-fed EWPs and antibiotic-treated EWPs. Serum biochemical analysis showed that EWPs fed an IgY-containing diet had both lower (p < 0.05) cholesterol and low-density lipoprotein compared to antibiotic-treated EWPs. Escherichia coli populations measured in IgY-fed EWP ileal contents, compared to the control group, were significantly reduced (p < 0.05). Enterococcus, Lactobacillus, Clostridium and Bifidobacterium populations were unaffected by the IgY treatment. Larger (p < 0.05) Enterococcus populations and lower (p < 0.05) expression levels of heat-stable enterotoxin b (STb) were observed in IgY-fed EWP caecal digesta compared to the control group. Enteric Lactobacillus significantly decreased (p < 0.05) in EWPs fed antibiotics while it was unaffected by IgY treatment. Dietary supplementation with anti-E. coli IgY has the potential to suppress enteric E. coli growth, but not Lactobacillus, Clostridium and Bifidobacterium. This promotes and maintains a healthy EWP intestinal environment. These findings suggest that IgY may be used as an alternative to antibiotics in EWP diets.

Application of an immunoglobulin Y-alkaline phosphatase bioconjugate as a diagnostic tool for influenza A virus

The diagnosis of influenza A virus is essential since it can be confused with influenza A like illness and lead to inaccurate drug prescription. In this study, the M2e peptide, a strategic antigen that is conserved in all virus subtypes, was used as a diagnostic marker of influenza A. For the first time, M2e-specific IgY antibody was covalently conjugated to alkaline phosphatase (ALP) enzyme in the presence of glutaraldehyde. The antibody-enzyme bioconjugate was characterized by fluorescence and Fourier-transform infrared spectroscopy. Subsequently, the diagnostic value of this bioconjugate was evaluated by direct sandwich ELISA using nasopharyngeal swab samples positive/negative for H1N1 and H3N2, which were previously analyzed by rRT-PCR for influenza. In conclusion, the M2e-specific IgY-ALP bioconjugate demonstrated positive results for Influenza A in samples that were diagnosed as Influenza A via the RT-PCR method.

Protective effect of chicken egg yolk immunoglobulins (IgY) against enterotoxigenic Escherichia coli K88 adhesion in weaned piglets

Background

Enterotoxigenic Escherichia coli K88 (E. coli K88) are considered as a major cause of diarrhea and death in newly weaned piglets. Oral passive immunization with chicken egg yolk immunoglobulins (IgY) have attracted considerable attention for treatment of gastrointestinal infection due to its high specificity. In this study it was estimated the protective effect of anti-K88 fimbriae IgY against E. coli K88 adhesion to piglet intestinal mucus in vitro and to investigate the potential use of IgY for controlling E. coli-induced diarrhea in weaned piglets in vivo.

Results

E. coli K88 was incubated with IgY for 24 h, and the bacterial growth profiles showed that specific IgY with a concentration higher than 5 mg/mL was observed to significantly inhibit the growth of E. coli K88 compared to nonspecific yolk powder in a liquid medium. Moreover, pretreatment with 50 mg/mL of IgY was found to significantly decrease the adhesion ability of E. coli K88 to porcine jejunal and ileal mucus, further supported by the observations from our immunofluorescence microscopic analysis. In vivo, administration of IgY successfully protected piglets from diarrhea caused by E. coli K88 challenge. Additionally, IgY treatment efficiently alleviated E. coli-induced intestinal inflammation in piglets as the gene expression levels of inflammatory cytokines TNF-α, IL-22, IL-6 and IL-1β in IgY-treated piglets remained unchanged after E. coli K88 infection. Furthermore, IgY significantly prevented E. coli K88 adhering to the jejunal and ileal mucosa of piglets with E. coli infection and significantly decreased E. coli and enterotoxin expression in colonic contents.

Conclusion

Outcome of the study demonstrated that IgY against the fimbrial antigen K88 was able to significantly inhibit the growth of E. coli K88, block the binding of E. coli to small intestinal mucus, and protect piglets from E. coli-induced diarrhea. These results indicate that passive immunization with IgY may be useful to prevent bacterial colonization and to control enteric diseases due to E. coli infection. The study has great clinical implication to provide alternative therapy to antibiotics in E coli induced diarrhea.

Electronic supplementary material

The online version of this article (10.1186/s12917-019-1958-x) contains supplementary material, which is available to authorized users.

Antimicrobial Stewardship in Veterinary Medicine

While antimicrobial resistance is already a public health crisis in human medicine, therapeutic failure in veterinary medicine due to antimicrobial resistance remains relatively uncommon. However, there are many pathways by which antimicrobial resistance determinants can travel between animals and humans: by close contact, through the food chain, or indirectly via the environment. Antimicrobial stewardship describes measures that can help mitigate the public health crisis and preserve the effectiveness of available antimicrobial agents. Antimicrobial stewardship programs have been principally developed, implemented, and studied in human hospitals but are beginning to be adapted for other applications in human medicine. Key learning from the experiences of antimicrobial stewardship programs in human medicine are summarized in this article-guiding the development of a stewardship framework suitable for adaptation and use in both companion animal and livestock practice. The antimicrobial stewardship program for veterinary use integrates infection prevention and control together with approaches emphasizing avoidance of antimicrobial agents. The 5R framework of continuous improvement that is described recognizes the importance of executive support; highly motivated organizations and teams (responsibility); the need to review the starting position, set objectives, and determine means of measuring progress and success; and a critical focus on reducing, replacing, and refining the use of antimicrobial agents. Significant issues that are currently the focus of intensive research include improved detection and diagnosis of infections, refined dosing regimens that are simultaneously effective while not selecting resistance, searches for alternatives to antimicrobial agents, and development of improved vaccines to enhance immunity and reduce disease.

Single Chain Fragment Variable (scFv) Antibodies Targeting the Spike Protein of Porcine Epidemic Diarrhea Virus Provide Protection against Viral Infection in Piglets

Porcine epidemic diarrhea virus (PEDV) is a highly contagious coronavirus that causes severe diarrhea and death in neonatal piglets. Passive immunization with neutralizing antibodies against PEDV is an effective prevention measure. In this study, single chain fragment variable (scFv) antibodies against PEDV were screened from the porcine scFv phage display library. After four rounds of biopanning, scFvs that showed higher affinity to the PEDV antigen were selected for further study. The scFv genes were cloned into the expression plasmid for recombinant protein expression. These scFvs were shown to inhibit PEDV infectivity by the plaque reduction neutralization assay. Immunofluorescence assay (IFA) revealed that the epitopes recognized by these scFvs were in the S1 region of the spike protein. The potential of scFvs to provide prevention against PEDV infections in piglets was further investigated. Piglets orally administered scFvs showed no to mild clinical symptoms, significantly less viral shedding, no mortality and no intestinal lesions. The field application also revealed that the survival rate of piglets was significantly increased by oral administration of scFvs. Our data support the potential role of scFvs in the prevention and treatment of PEDV infection.

How Can the Value and Use of Egg Yolk Be Increased?

The major driving force for the egg consumption in the United States over the past few decades was processed egg. However, the consumption of egg through the processed egg reached the plateau in recent years because of the imbalance in the demands between the egg white and yolk products. The consumer demands for egg white products are very high while those for the egg yolk, the co-product of dried egg white, are low because of the negative perceptions on egg yolk. Two key approaches that can be used to increase the value and use of egg yolk are: (1) developing new commodity products by fractionating egg yolk and apply them in various food processing, and (2) separating functional proteins and lipids from yolk and use them as is or further develop functional peptides and functional lipids and use them as pharmaceutical, nutraceutical, and cosmeceutical agents. These approaches can diversify the use of egg yolk, which eventually will help increase the consumption of egg. This review (1) discusses the current use of egg yolk products and the development of new functional commodity products from egg yolk, (2) review the important functional components in egg yolk and overview the current separation methods and their applications, (3) discuss the production of functional peptides and lipids using the separated egg proteins and lipids, and (4) suggest the future directions for the best use of egg yolk components. Development of scale-up production methods, which is vital for the practical applications, is discussed when appropriate.

Egg Yolk Immunoglobulin Supplementation Prevents Rat Liver from Aflatoxin B1-Induced Oxidative Damage and Genotoxicity

Egg yolk immunoglobulins (IgY), as nutraceutical supplement for therapeutic or prophylactic intervention, have been extensively studied. The effects of IgY on small molecular toxin-induced toxicity in animals are unclear. In the present study, the protection of highly purified and specific anti-AFB₁ IgY against AFB₁-induced genotoxicity and oxidative damage on the rat liver model were investigated. Our results revealed that AFB₁ induced significant oxidative damage markers, as well as AFB₁-induced protein expression in antioxidant, pro- and antiapoptosis processes in rat liver. These effects could be significantly inhibited by cogavage with anti-AFB₁ IgY in a dose-dependent manner. However, anti-AFB₁ IgY did not significantly induce hepatic CAT and SOD1. To explore mechanisms, metabolite experiments were established to evaluate the influence of anti-AFB₁ IgY on the absorption of AFB₁ in rats. Middle and high doses of anti-AFB₁ IgY reduced hepatic AFB₁-DNA adducts by 43.3% and 52.9%, AFB₁- N⁷-guanine urinary adducts by 19.6% and 34.4%, and AFB₁-albumin adducts by 10.5% and 21.1%, respectively. The feces of high dose anti-AFB₁ IgY cogavaged rats contained approximately 2-fold higher AFB₁ equivalents at 3-6 h after ingestion than AFB₁ group feces, indicating IgY inhibited AFB₁ uptake. These results had provided insight that anti-AFB₁ IgY could prevent animal organs from damage caused by AFB₁ and will be beneficial for the application of detoxification antibody as a supplement in food.

Specific egg yolk antibodies (IgY) confer protection against Acinetobacter baumannii in a murine pneumonia model

AIM

Acinetobacter baumannii, an increasingly serious health threat, is considered as one of the six most dangerous microbes of high mortality rate. However, treatment of its infections is difficult because of the lack of efficient antibiotic or commercial vaccines. Passive immunization through administration of specific antibodies such as IgY, could be an attractive practical solution.

METHODS AND RESULTS

In the current study, antigenicity of two recombinant outer membrane proteins (OmpA and Omp34) as well as inactivated whole cell of A. baumannii was assessed by ELISA. Moreover, prophylactic effects of specific IgY antibodies (avian antibody) raised against these antigens were evaluated in a murine pneumonia model. The specific IgY antibodies had various prophylactic effects in the pneumonia model. OmpA was the most potent antigen in terms of triggering antibody and conferring protection. While a synergic effect was observed in ELISA for antibodies raised against a combination of OmpA and Omp34 (which are known as Omp33-36 and Omp34 kDa), an antagonistic effect was unexpectedly seen in challenges. The reason for this phenomenon remains to be precisely addressed.

CONCLUSION

All the specific IgY antibodies could protect mice against pneumonia caused by A. baumannii.

SIGNIFICANCE AND IMPACT OF THE STUDY

The specific IgY antibodies could be employed as a pharmaceutical against pneumonia caused by A. baumannii.

IgY antibodies for the immunoprophylaxis and therapy of respiratory infections

Emergence of drug resistance among the causative organisms for respiratory tract infections represents a critical challenge to the global health care community. Further, although vaccination can prevent disease, vaccine development is impeded by several factors. Therefore, novel approaches to treat and manage respiratory infections are urgently needed. Passive immunization represents a possible alternative to meet this need. Immunoglobulin Y antibodies (IgYs) from the yolk of chicken eggs have previously been used against bacterial and viral infections in human and animals. Their advantages include lack of reaction with mammalian Fc receptors, low production cost, and ease of extraction. Compared to mammalian IgGs, they have higher target specificity and greater binding avidity. They also possess remarkable pathogen-neutralizing activity in the respiratory tract and lungs. In this review, we provide an overview of avian IgYs and describe their potential therapeutic applications for the prevention and treatment of respiratory infections.

Global restriction of using antibiotic growth promoters and alternative strategies in poultry production

A growing global concern of antibiotic use in poultry diets due to its potential adverse effects on birds and human health, food safety and the environment has led to a complete ban or restricted use in some countries, and, at the same time, expanding options for the use of alternative feed additives. Multiple, rather than a single additive may replace antibiotic growth promoters (AGPs) in poultry. Blending of feeding additives and hygienic farm management, vaccination and biosecurity may help achieve good intestinal health, stabilise enteric ecosystems and result in sustainable and cost effective production performance of birds. Moreover, controlling unsolicited ingredients at the production level must have the support of different markets responsible for the supply of safe and quality poultry products for consumers. This requires the further increase and diversification of value added poultry products and the expansion of their markets through strategic planning and gradual limitation of live bird markets. More research is warranted in order to explore suitable, reliable and cost effective alternatives to AGPs for commercial use, and strategic poultry value chain development.

Effects of specific egg yolk immunoglobulin on pan-drug-resistant Acinetobacter baumannii

With the growing emergence of pan-drug-resistant Acinetobacter baumannii (PDR-Ab) strains in clinical, new strategies for the treatment of PDR-Ab infections are urgently needed. Egg yolk immunoglobulin (IgY) as a convenient and inexpensive antibody has been widely applied to the therapy of infectious diseases. The aim of this study was to produce IgY specific to PDR-Ab and investigate its antibacterial effects in vitro and in vivo. IgYs specific to two PDR-Ab strains were produced by immunizing hens with formaldehyde inactivated PDR-Ab cells and isolated from yolks with a purity of 90% by water dilution, salt precipitations and ultrafiltration. IgYs showed high titers when subjected to an ELISA and inhibited the growth of PDR-Ab in a dose-dependent manner in liquid medium. Scanning electron microscopy assay showed structural modification and aggregation of PDR-Ab treated with specific IgYs. Freshly cultured PDR-Ab cells were nasally inhaled in BALB/c mice to induce acute pneumonia. The infected mice were intraperitoneally injected with specific IgYs using cefoperazone/sulbactam and dexamethasone as positive controls. The IgYs specific to PDR-Ab lowered the mortality of mice with PDR-Ab-induced acute pneumonia, decreased the level of TNF-α and IL-1β in serum and reduced inflammation in lung tissue. Specific IgY has the potential to be used as a new therapeutic approach for the treatment of A. baumannii-induced infections.

Anti-Vibriocholerae IgY Antibody Inhibits Mortality in Suckling Mice Model

BACKGROUND

Regarding to the importance of cholera in Iran and the potential advantages of egg yolk antibody (IgY) for immunotherapy, the aim of this study was to produce IgY antibody against V. cholerae Lipopolysaccharide (LPS) and determine its potential for V. cholerae treatment.

METHODS

LPS was prepared, and the Anti-V. cholerae LPS IgY was purified from egg yolk and serially diluted in phosphate-buffered saline (PBS), mixed with V. cholerae and then gavaged into several groups of suckling mice.

RESULTS

The yield of Anti-LPS IgY extraction was 40 mg/Egg yolk. The results demonstrated that up to approximately 75 ng of IgY can detect specifically V. cholerae. The lowest protective dose of anti-V. cholerae LPS IgY was 2.5 μg.

CONCLUSIONS

The produced anti-Vibrio LPS specific IgY showed a good reactivity with its specific antigen and it may use as a complimentary oral immunotherapy for cholera disease.

Development and Validation of Monoclonal Antibody-Based Antigen Capture ELISA for Detection of Group A Porcine Rotavirus

Porcine rotavirus-A (PoRVA) is one of the common causes of mild to severe dehydrating diarrhea, leading to losses in weaning and postweaning piglets. A rapid, highly specific, and sensitive antigen-capture enzyme-linked immunosorbent assay (AC-ELISA) was developed for detection of PoRVA, by using VP6 (a highly conserved and antigenic protein of group-A rotavirus)-directed rabbit polyclonal antibodies (capture antibody) and murine monoclonal antibodies (detector antibody). The detection limit of AC-ELISA was found to be equal to that of conventional reverse transcription-polymerase chain reaction (RT-PCR; about 10^2.5 TCID₅₀/mL). For validation of the in-house AC-ELISA, 295 porcine fecal/diarrhea samples, collected from different provinces of China, were evaluated and compared with conventional RT-PCR and TaqMan RT-quantitative PCR (qPCR). The sensitivity and specificity of this in-house AC-ELISA relative to RT-qPCR were found to be 91.67% and 100%, respectively, with the strong agreement (kappa = 0.972) between these two techniques. Total detection rate with AC-ELISA, conventional RT-PCR, and RT-qPCR were found to be 11.2%, 11.5%, and 12.2%, respectively, without any statistical significant difference. Moreover, AC-ELISA failed to detect any cross-reactivity with porcine epidemic diarrhea virus, transmissible gastroenteritis virus, pseudorabies virus, and porcine circovirus-2. These results suggested that our developed method was rapid, highly specific, and sensitive, which may help in large-scale surveillance, timely detection, and preventive control of rotavirus infection in porcine farms.

EMA and EFSA Joint Scientific Opinion on measures to reduce the need to use antimicrobial agents in animal husbandry in the European Union, and the resulting impacts on food safety (RONAFA)

EFSA and EMA have jointly reviewed measures taken in the EU to reduce the need for and use of antimicrobials in food-producing animals, and the resultant impacts on antimicrobial resistance (AMR). Reduction strategies have been implemented successfully in some Member States. Such strategies include national reduction targets, benchmarking of antimicrobial use, controls on prescribing and restrictions on use of specific critically important antimicrobials, together with improvements to animal husbandry and disease prevention and control measures. Due to the multiplicity of factors contributing to AMR, the impact of any single measure is difficult to quantify, although there is evidence of an association between reduction in antimicrobial use and reduced AMR. To minimise antimicrobial use, a multifaceted integrated approach should be implemented, adapted to local circumstances. Recommended options (non-prioritised) include: development of national strategies; harmonised systems for monitoring antimicrobial use and AMR development; establishing national targets for antimicrobial use reduction; use of on-farm health plans; increasing the responsibility of veterinarians for antimicrobial prescribing; training, education and raising public awareness; increasing the availability of rapid and reliable diagnostics; improving husbandry and management procedures for disease prevention and control; rethinking livestock production systems to reduce inherent disease risk. A limited number of studies provide robust evidence of alternatives to antimicrobials that positively influence health parameters. Possible alternatives include probiotics and prebiotics, competitive exclusion, bacteriophages, immunomodulators, organic acids and teat sealants. Development of a legislative framework that permits the use of specific products as alternatives should be considered. Further research to evaluate the potential of alternative farming systems on reducing AMR is also recommended. Animals suffering from bacterial infections should only be treated with antimicrobials based on veterinary diagnosis and prescription. Options should be reviewed to phase out most preventive use of antimicrobials and to reduce and refine metaphylaxis by applying recognised alternative measures.