Egg yolk IgY antibodies: A therapeutic intervention against group A rotavirus in calves

pH-responsive multi-network composite cellulose-based hydrogels for stable delivery of oral IgY-Fab fragments

Yolk immunoglobulin (IgY) is perfect supplement to mammalian immunoglobulin G in passive immune protection but with poor delivery stability. This work succeeded in pH-responsive oral delivery of IgY-Fab fragments with cellulose based multi-network composite hydrogels. Data displayed that the hydrogel 2 showed superior mechanical properties and load performance (encapsulation efficiency of 99.25% and loading capacity of 45.11 mg/100 mg). The stability of the released Fab was confirmed by HPLC with Fab purity up to 79.65% at the end of digestion. The FTIR spectra revealed the potential interactions between Fab and the hydrogel matrix of the formation of hydrogen bonds or electrostatic interactions between the groups of -OH, -CH2, and -COO-. The excellent rehydration of the hydrogels wouldn't be impacted by low-temperature freeze drying. In sum, this work is of great significance to the development of Fab-themed health-care food, intensive processing of poultry eggs and the economic construction of related industries.

Immune Portrayal of a New Therapy Targeting Microbiota in an Animal Model of Psoriasis

BACKGROUND

Despite all the available treatments, psoriasis remains incurable; therefore, finding personalized therapies is a continuous challenge. Psoriasis is linked to a gut microbiota imbalance, highlighting the importance of the gut-skin axis and its inflammatory mediators. Restoring this imbalance can open new perspectives in psoriasis therapy. We investigated the effect of purified IgY raised against pathological human bacteria antibiotic-resistant in induced murine psoriatic dermatitis (PSO).

METHODS

To evaluate the immune portrayal in an imiquimod experimental model, before and after IgY treatment, xMAP array and flow cytometry were used.

RESULTS

There were significant changes in IL-1α,β, IL-5, IL-6, IL-9, IL-10, IL-12 (p70), IL-13, IL-15, IL-17a, IFN-γ, TNF-α, IP-10/CXCL10, MCP-1/CCL2, MIP-1α/CCL3, MIP-1β/CCL4, MIG/CXCL9, and KC/CXCL1 serum levels. T (CD3ε+), B (CD19+) and NK (NK1.1+) cells were also quantified. In our model, TNF-α, IL-6, and IL-1β cytokines and CXCL1 chemokine have extremely high circulatory levels in the PSO group. Upon experimental therapy, the cytokine serum values were not different between IgY-treated groups and spontaneously remitted PSO.

CONCLUSIONS

Using the murine model of psoriatic dermatitis, we show that the orally purified IgY treatment can lead to an improvement in skin lesion healing along with the normalization of cellular and humoral immune parameters.

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.

Egg Yolk Antibody for Passive Immunization: Status, Challenges, and Prospects

The immunoglobulin Y (IgY) derived from hyperimmune egg yolk is a promising passive immune agent to combat microbial infections in humans and livestock. Numerous studies have been performed to develop specific egg yolk IgY for pathogen control, but with limited success. To date, the efficacy of commercial IgY products, which are all delivered through an oral route, has not been approved or endorsed by any regulatory authorities. Several challenging issues of the IgY-based passive immunization, which were not fully recognized and holistically discussed in previous publications, have impeded the development of effective egg yolk IgY products for humans and animals. This review summarizes major challenges of this technology, including in vivo stability, purification, heterologous immunogenicity, and repertoire diversity of egg yolk IgY. To tackle these challenges, potential solutions, such as encapsulation technologies to stabilize IgY, are discussed. Exploration of this technology to combat the COVID-19 pandemic is also updated in this review.

Development of an IgY-Based Treatment to Control Bovine Coronavirus Diarrhea in Dairy Calves

Bovine Coronavirus (BCoV) is a major pathogen associated with neonatal calf diarrhea. Standard practice dictates that to prevent BCoV diarrhea, dams should be immunized in the last stage of pregnancy to increase BCoV-specific antibody (Ab) titers in serum and colostrum. For the prevention to be effective, calves need to suck maternal colostrum within the first six to twelve hours of life before gut closure to ensure a good level of passive immunity. The high rate of maternal Ab transfer failure resulting from this process posed the need to develop alternative local passive immunity strategies to strengthen the prevention and treatment of BCoV diarrhea. Immunoglobulin Y technology represents a promising tool to address this gap. In this study, 200 laying hens were immunized with BCoV to obtain spray-dried egg powder enriched in specific IgY Abs to BCoV on a large production scale. To ensure batch-to-batch product consistency, a potency assay was statistically validated. With a sample size of 241, the BCoV-specific IgY ELISA showed a sensitivity and specificity of 97.7% and 98.2%, respectively. ELISA IgY Abs to BCoV correlated with virus-neutralizing Ab titers (Pearson correlation, R2 = 0.92, p < 0.001). Most importantly, a pilot efficacy study in newborn calves showed a significant delay and shorter duration of BCoV-associated diarrhea and shedding in IgY-treated colostrum-deprived calves. Calves were treated with milk supplemented with egg powder (final IgY Ab titer to BCoV ELISA = 512; VN = 32) for 14 days as a passive treatment before a challenge with BCoV and were compared to calves fed milk with no supplementation. This is the first study with proof of efficacy of a product based on egg powder manufactured at a scale that successfully prevents BCoV-associated neonatal calf diarrhea.

IgY antibodies: The promising potential to overcome antibiotic resistance

Antibiotic resistant bacteria are a growing threat to global health security. Whilst the emergence of antimicrobial resistance (AMR) is a natural phenomenon, it is also driven by antibiotic exposure in health care, agriculture, and the environment. Antibiotic pressure and inappropriate use of antibiotics are important factors which drive resistance. Apart from their use to treat bacterial infections in humans, antibiotics also play an important role in animal husbandry. With limited antibiotic options, alternate strategies are required to overcome AMR. Passive immunization through oral, nasal and topical administration of egg yolk-derived IgY antibodies from immunized chickens were recently shown to be effective for treating bacterial infections in animals and humans. Immunization of chickens with specific antigens offers the possibility of creating specific antibodies targeting a wide range of antibiotic-resistant bacteria. In this review, we describe the growing global problem of antimicrobial resistance and highlight the promising potential of the use of egg yolk IgY antibodies for the treatment of bacterial infections, particularly those listed in the World Health Organization priority list.

Preclinical Assessment of IgY Antibodies Against Recombinant SARS-CoV-2 RBD Protein for Prophylaxis and Post-Infection Treatment of COVID-19

Within the framework of the current COVID-19 pandemic, there is a race against time to find therapies for the outbreak to be controlled. Since vaccines are still tedious to develop and partially available for low-income countries, passive immunity based on egg-yolk antibodies (IgY) is presented as a suitable approach to preclude potential death of infected patients, based on its high specificity/avidity/production yield, cost-effective manufacture, and ease of administration. In the present study, IgY antibodies against a recombinant RBD protein of SARS-CoV-2 were produced in specific-pathogen-free chickens and purified from eggs using a biocompatible method. In vitro immunoreactivity was tested, finding high recognition and neutralization values. Safety was also demonstrated prior to efficacy evaluation, in which body weight, kinematics, and histopathological assessments of hamsters challenged with SARS-CoV-2 were performed, showing a protective effect administering IgY intranasally both as a prophylactic treatment or a post-infection treatment. The results of this study showed that intranasally delivered IgY has the potential to both aid in prevention and in overcoming COVID-19 infection, which should be very useful to control the advance of the current pandemic and the associated mortality.

Developing a Biosensor-Based Immunoassay to Detect HPV E6 Oncoprotein in the Saliva Rinse Fluid of Oral Cancer Patients

Transmission of Human papillomavirus (HPVs) is faithfully associated with carcinogenesis of oral cavity and oropharyngeal cancers. Therefore, clinical researchers may need to generate customized antibodies for the upcoming ELISA-based analysis to discover rare but valuable biomarkers. The aim of study was to develop and generate a biosensor-based immunoassay for early screening HPV-related oral cancer via saliva rinse fluid analysis. A peptide fragment of high-risk HPV subtype 16/18 protein, E6 protein (HP-1 protein sequence 48–66), was designed and synthesized, followed by the generation of polyclonal antibodies (anti-HP1 IgY) in our university-based laboratories. The titer and specificity of antibodies were determined by enzyme-linked immunosorbent assay (ELISA), and the Surface Plasmon Resonance (SPR) biosensor-based method was developed. Kinetic analyses by SPR confirmed that this designed peptide showed a high affinity with its generated polyclonal antibodies. Saliva fluid samples of thirty oral cancer patients and 13 healthy subjects were analyzed. SPR indicated that 26.8% of oral cancer patients had higher resonance unit (ΔRU) values than normal subjects. In conclusion, we developed a biosensor-based immunoassay to detect HPV E6 oncoprotein in the saliva rinse fluid for early screening and discrimination of HPV-related oral cancer patients.

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.

Exploring the potential usefulness of IgY for antiviral therapy: A current review

Immunoglobulin yolk (IgY) is therapeutic antibodies presented in yolk eggs of birds, reptiles, and amphibians. These proteins produced by the immune system of the animal, are capable of neutralizing antigenic molecules, including viral antigens, fulfilling a role in the body defense. The specificity of these antibodies and the facility for their production, make these molecules capable of being used as tools for diagnosis and immunotherapy. Regarding this last aspect, it is common knowledge that the field of virology, is racing against time in the development of new drugs and vaccines to try to contain pandemics and local epidemics and, in counterproposal, avian antibodies are neutralizing molecules that can help in the control and spread of disease. These molecules have been explored for years and currently chicken eggs are produced in large quantities from the animal's immunization against a specific pathogen. Thus, on this subject, this review made a survey of these researches and presents a summary of all the successful cases and perspectives in the use of IgYs as tools for viral immunization.

Bovine Immunology: Implications for Dairy Cattle

The growing world population (7.8 billion) exerts an increased pressure on the cattle industry amongst others. Intensification and expansion of milk and beef production inevitably leads to increased risk of infectious disease spread and exacerbation. This indicates that improved understanding of cattle immune function is needed to provide optimal tools to combat the existing and future pathogens and improve food security. While dairy and beef cattle production is easily the world's most important agricultural industry, there are few current comprehensive reviews of bovine immunobiology. High-yielding dairy cattle and their calves are more vulnerable to various diseases leading to shorter life expectancy and reduced environmental fitness. In this manuscript, we seek to fill this paucity of knowledge and provide an up-to-date overview of immune function in cattle emphasizing the unresolved challenges and most urgent needs in rearing dairy calves. We will also discuss how the combination of available preventative and treatment strategies and herd management practices can maintain optimal health in dairy cows during the transition (periparturient) period and in neonatal calves.

Immunoglobulin Y for Potential Diagnostic and Therapeutic Applications in Infectious Diseases

Antiviral, antibacterial, and antiparasitic drugs and vaccines are essential to maintaining the health of humans and animals. Yet, their production can be slow and expensive, and efficacy lost once pathogens mount resistance. Chicken immunoglobulin Y (IgY) is a highly conserved homolog of human immunoglobulin G (IgG) that has shown benefits and a favorable safety profile, primarily in animal models of human infectious diseases. IgY is fast-acting, easy to produce, and low cost. IgY antibodies can readily be generated in large quantities with minimal environmental harm or infrastructure investment by using egg-laying hens. We summarize a variety of IgY uses, focusing on their potential for the detection, prevention, and treatment of human and animal infections.

A new passive immune strategy based on IgY antibodies as a key element to control neonatal calf diarrhea in dairy farms

Background

Neonatal diarrhea remains one of the main causes of morbi-mortality in dairy calves under artificial rearing. It is often caused by infectious agents of viral, bacterial, or parasitic origin. Cows vaccination and colostrum intake by calves during the first 6 h of life are critical strategies to prevent severe diarrhea but these are still insufficient. Here we report the field evaluation of a product based on IgY antibodies against group A rotavirus (RVA), coronavirus (CoV), enterotoxigenic Escherichia coli, and Salmonella sp. This product, named IgY DNT, has been designed as a complementary passive immunization strategy to prevent neonatal calf diarrhea. The quality of the product depends on the titers of specific IgY antibodies to each antigen evaluated by ELISA. In the case of the viral antigens, ELISA antibody (Ab) titers are correlated with protection against infection in calves experimentally challenged with RVA and CoV (Bok M, et al., Passive immunity to control bovine coronavirus diarrhea in a dairy herd in Argentina, 2017), (Vega C, et al., Vet Immunol Immunopathol, 142:156–69, 2011), (Vega C, et al., Res Vet Sci, 103:1–10, 2015). To evaluate the efficiency in dairy farms, thirty newborn Holstein calves were randomly assigned to IgY DNT or control groups and treatment initiated after colostrum intake and gut closure. Calves in the IgY DNT group received 20 g of the oral passive treatment in 2 L of milk twice a day during the first 2 weeks of life. Animals were followed until 3 weeks of age and diarrhea due to natural exposure to infectious agents was recorded during all the experimental time.

Results

Results demonstrate that the oral administration of IgY DNT during the first 2 weeks of life to newborn calves caused a delay in diarrhea onset and significantly reduced its severity and duration compared with untreated calves. Animals treated with IgY DNT showed a trend towards a delay in RVA infection with significantly shorter duration and virus shedding compared to control calves.

Conclusions

This indicates that IgY DNT is an effective product to complement current preventive strategies against neonatal calf diarrhea in dairy farms. Furthermore, to our knowledge, this is the only biological product available for the prevention of virus-associated neonatal calf diarrhea.

Efficacy of the spray-drying treatment to inactivate the bovine leukemia virus in bovine colostrum

Previous studies have shown the presence of bovine leukemia virus (BLV) in colostrum and milk of naturally infected cows. The relationship between virus or provirus and specific antibodies in these secretions is particular to each infected cow and will probably determine whether the consumption of colostrum or milk from these naturally infected dams provides an infective or a protective effect in recipient calves. Our recent findings suggest that this issue is a key point in BLV transmission in very young calves. Based on this, the aim of the present study was to determine the effect of the spray-drying treatment of colostrum on BLV infectivity. The treatment was done on scale-down conditions, using fresh colostrum from BLV-negative cows spiked with infective BLV. Residual infectivity was tested in susceptible lambs. Lambs inoculated with colostrum spiked with BLV-infected cells or cell-free BLV showed evidence of infection 60 d after inoculation, whereas none of the lambs inoculated with spray-dried colostrum showed evidence of infection 60 d after inoculation. These results provide direct evidence that the experimental spray-drying process used in this study was effective in inactivating infectious BLV in colostrum. These findings suggest that the risk for BLV transmission could be reduced if milk and colostrum were treated by spray-drying prior to consumption in dairy facilities. The effect of spray-drying on the functional properties and stability of the antibodies present in colostrum under long-term storage should be further investigated.

Egg yolk antibodies (IgY) and their applications in human and veterinary health: A review

Egg yolk constitutes a relevant alternative source of antibodies. It presents some advantages over mammalian serum immunoglobulins regarding productivity, animal welfare and specificity. The main immunoglobulin present in avian blood (IgY) is transmitted to their offspring and accumulates in egg yolks, which enables the non-invasive harvesting of high amounts of antibodies. Moreover, due to structural differences and phylogenetic distance, IgY is more suitable for diagnostic purposes than mammalian antibodies, since it does not react with certain components of the human immune system and displays greater avidity for mammalian conserved proteins. IgY has been extensively used in health researches, as both therapeutic and diagnostic tool. This article aims to review its applications in both human and veterinary health.

Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). Although efficient eradication programs have been successfully implemented in most European countries and Oceania, BLV infection rates are still high worldwide. BLV naturally infects cattle, inducing a persistent infection with diverse clinical outcomes. The virus infects lymphocytes and integrates a DNA intermediate as a provirus into the genome of the cells. Therefore, exposure to biological fluids contaminated with infected lymphocytes potentially spreads the virus. Vertical transmission may occur in utero or during delivery, and about 10% of calves born to BLV-infected dams are already infected at birth. Most frequently, transmission from dams to their offspring occurs through the ingestion of infected colostrum or milk. Therefore, although EBL is not a disease specific to the neonatal period, during this period the calves are at special risk of becoming infected, especially in dairy farms, where they ingest colostrum and/or raw milk either naturally or artificially. Calves infected during the first week of life could play an active role in early propagation of BLV to susceptible animals. This review discusses the main factors that contribute to neonatal BLV infection in dairy herds, as well as different approaches and management practices that could be implemented to reduce the risk of BLV transmission during this period, aiming to decrease BLV infection in dairy herds.

Chicken Egg Yolk Antibodies (IgY) for Prophylaxis and Treatment of Rotavirus Diarrhea in Human and Animal Neonates: A Concise Review

The rotavirus-induced diarrhea of human and animal neonates is a major public health concern worldwide. Until recently, no effective therapy is available to specifically inactivate the rotavirion particles within the gut. Passive immunotherapy by oral administration of chicken egg yolk antibody (IgY) has emerged of late as a fresh alternative strategy to control infectious diseases of the alimentary tract and has been applied in the treatment of diarrhea due to rotavirus infection. The purpose of this concise review is to evaluate evidence on the properties and performance of anti-rotavirus immunoglobulin Y (IgY) for prevention and treatment of rotavirus diarrhea in human and animal neonates. A survey of relevant anti-rotavirus IgY basic studies and clinical trials among neonatal animals (since 1994-2015) and humans (since 1982-2015) have been reviewed and briefly summarized. Our analysis of a number of rotavirus investigations involving animal and human clinical trials revealed that anti-rotavirus IgY significantly reduced the severity of clinical manifestation of diarrhea among IgY-treated subjects relative to a corresponding control or placebo group. The accumulated information as a whole depicts oral IgY to be a safe and efficacious option for treatment of rotavirus diarrhea in neonates. There is however a clear need for more randomized, placebo controlled and double-blind trials with bigger sample size to further solidify and confirm claims of efficacy and safety in controlling diarrhea caused by rotavirus infection especially among human infants with health issues such as low birth weights or compromised immunity in whom it is most needed.

Detection of kanamycin and gentamicin residues in animal-derived food using IgY antibody based ic-ELISA and FPIA

Our aim in this study is to show that IgY antibody based immunoassays could be used to detect antibiotic residues in animal-derived food. Briefly, full antigens of gentamicin (Gent) and kanamycin (Kana) were used to immunize the laying chickens to prepare IgY antibodies. Then, these antibodies were evaluated by FPIA and ic-ELISA to detect Gent/Kana in animal-derived samples. The IC₅₀ of FPIA and ic-ELISA based anti-Gent IgY were 7.70±0.6μg/mL and 0.32±0.06μg/mL, respectively. The IC₅₀ of FPIA and ic-ELISA based anti-Kana IgY were 7.97±0.9μg/mL and 0.15±0.01μg/mL. The limits of detection (LOD, IC₁₀) for FPIA based anti-Gent/Kana IgY were 0.17 and 0.007μg/mL, respectively. The LOD for ic-ELISA were both 0.001μg/mL. These results indicated that the ic-ELISA might more suitable for antibiotic residues detection than FPIA.

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.

Serum interleukin-6 as a prognostic marker in neonatal calf diarrhea

Neonatal calf diarrhea is still one of the most important diseases in calf rearing, and severe diarrhea has a marked effect on animal welfare. Furthermore, significant economic losses can result from this disease due to high mortality rates, high medical costs, and low weight gain. To avoid a fatal outcome of the disease, it is crucial that vulnerable calves are identified as early as possible. Interleukin-6 is described as an early and reliable prognostic marker in several diseases. In this study, 20 scouring calves were tested by ELISA for their IL-6 serum concentrations. Samples were collected twice, at the beginning of diarrhea and 7 to 10 d later. Regarding the clinical outcome after 7 to 10 d, calves were classified as recovered or nonrecovered. A receiver operating characteristic analysis was conducted to determine the prognostic value of IL-6 for the progress of clinical symptoms. At the beginning of diarrhea, the IL-6 concentration was significantly higher in nonrecovering calves compared with those that recover 7 to 10 d after the onset of diarrhea. Interleukin-6 proved to be a useful additional parameter in the clinical examination. High initial IL-6 values can support the decision for closer monitoring and an adapted therapeutic strategy for the respective calves. This may help to prevent unnecessary animal suffering and reduce economic losses.