Immune Response In Chickens Research Articles

Identification of immunogenic antigens and evaluation of vaccine candidates against Clostridium perfringens

Necrotic enteritis (NE) caused by Clostridium perfringens (C. perfringens) has resulted in significant losses for the poultry industry worldwide. Currently, there is no widely promoted vaccine for NE. In this study, immunoprecipitation (IP) was employed to isolate immunogenic proteins of C. perfringens, and 118 potential candidate antigens were identified through liquid chromatography-mass spectrometry/mass spectrometry (LC–MS/MS). From these, three candidate antigen proteins were selected based on their predicted antigenicity, hydrophilicity, stability, and transmembrane signalling properties: ArcB (an ornithine aminotransferase), TmpC (a probable membrane lipoprotein), and EntB (a possible enterotoxin). These three proteins were successfully produced in large quantities using Escherichia coli (E. coli), with confirmed good solubility. Both in vitro and in vivo research demonstrated that these antigens possess strong immunogenicity, eliciting robust antigen-specific humoral and cellular immune responses in chickens and mitigating NE symptoms caused by C. perfringens. The candidate antigens identified through immunoproteomics hold potential as subunit vaccines against C. perfringens infection.

Broadly cross-reactive immune responses in chickens immunized with chimeric virus-like particles of nodavirus displaying the M2e originated from avian and human influenza A viruses

Avian influenza A viruses (IAVs) pose a persistent threat to poultry industry worldwide, despite the presence of vaccines. Additionally, reverse-zoonosis transmission potentially introduces human-originated IAVs into poultry and complicates the efforts to control the spread of influenza. Current avian influenza vaccines are primarily based upon the rapidly mutating hemagglutinin (HA) and neuraminidase (NA) glycoproteins, which limit their efficacy against diverse strains of IAVs. Hence, the highly conserved ectodomains of matrix 2 protein (M2e) of IAVs are widely studied as alternatives to the HA and NA. However, the differences in the M2e amino acid sequences between avian and human IAVs generate antibodies that do not cross-react reciprocally with IAVs from other origins. To broaden and enhance the immunogenicity of M2e, we fused two copies each of the M2e derived from avian and human IAVs at the C-terminal end of the Macrobrachium rosenbergii nodavirus (MrNV) capsid protein (NvC). Transmission electron microscopic and dynamic light scattering analyses revealed that the chimeric protein self-assembled into virus-like particles (VLPs). Immunization of chickens with the chimeric VLPs demonstrated a robust induction of broadly reactive immune responses against both the M2e of avian and human IAVs. Additionally, the chimeric VLPs elicited the production of cytotoxic T lymphocytes (CTL), macrophages, as well as a well-balanced Th1 and Th2 population, indicating their potential in activating cell-mediated immune responses in chickens. Furthermore, the chimeric VLPs triggered the production of both Th1- and Th2-cytokines, attesting their potential in mounting a robust and balanced immune response in avian species. This study demonstrated the potential of these chimeric VLPs in stimulating and broadening cross-reactive immune responses in chickens against both avian and human IAVs.

Identification and Functional Analysis of Novel Long Intergenic RNA in Chicken Macrophages Infected with Avian Pathogenic Escherichia coli.

Avian pathogenic E. coli (APEC), a widespread bacterium, results in serious economic losses to the poultry industry annually, and it poses a threat to human health due to the contaminated retail poultry meat and eggs. Recently, it has been demonstrated that long non-coding RNAs played important roles in regulating gene expression and the animal immune response. This study aimed to systematically explore the function of the novel long intergenic non-coding transcript, lincRNA-73240, upon APEC infection. A bioinformatics analysis indicated that lincRNA-73240 had no coding ability and a relative stable secondary structure with multiple hairpin rings. Moreover, the RT-qPCR results showed that lincRNA-73240 was highly expressed in lungs, heart, liver, spleen, cecum tonsils, thymus, ileum, bursa of Fabricius, harderian gland, and muscles in comparison to the cerebrum. Additionally, overexpression of lincRNA-73240 can promote the expression levels of inflammation, apoptosis, autophagy, and oxidative stress-related genes, as well as the production of reactive oxygen species (ROS), malondialdehyde (MDA), and nitric oxide (NO) upon APEC infection, which lead to cellular injury and apoptosis. These findings collectively establish a foundation for the study of the biological function of chicken lincRNA-73240 and provide a theoretical basis for further research on the molecular mechanisms of the chicken immune response.

Evaluation of the immune responses of biological adjuvant bivalent vaccine with three different insertion modes for ND and IBD

ABSTRACT Infectious bursal disease (IBD) is a widespread problem in the poultry industry, and vaccination is the primary preventive method. However, moderately virulent vaccines may damage the bursa, necessitating the development of a safe and effective vaccine. The Newcastle disease virus (NDV) has been explored as a vector for vaccine development. In this study, reverse genetic technology was used to obtain three recombinant viruses, namely, rClone30-VP2L (P/M)-chGM-CSF (NP), rClone30-chGM-CSF (P/M)-VP2L (NP), and rClone30-VP2L-chGM-CSF (P/M). Animal experiments showed that the three biological adjuvant bivalent vaccines effectively increased anti-NDV and anti-infectious bursal disease virus (IBDV) titres, enhancing both humoral and cellular immune responses in chickens without leading to any harm. Amongst the three biological adjuvant bivalent vaccines, the rClone30-chGM-CSF (P/M)-VP2L (NP) group had higher levels of anti-NDV antibodies at 14 days after the first immunization and stimulated a greater humoral immune response in 7–10 days. While, the rClone30-VP2L (P/M)-chGM-CSF (NP) group was the most effective in producing a higher level of IBDV antibody response. In conclusion, these three vaccines can induce immune responses more rapidly and effectively, streamline production processes, be cost-effective, and provide a new avenue for the development of Newcastle disease (ND) and IBD bivalent vaccines

PTEN regulated by gga-miR-20a-5p is involved in chicken macrophages inflammatory response to APEC infection via autophagy

Colibacillosis, a bacterial disease caused by avian pathogenic E. coli (APEC), is a prevalent condition in the poultry industry, resulting in substantial economic losses annually. Previously, we identified PTEN as a crucial candidate gene that may play a significant role in chicken's immune response to APEC infection. Bioinformatics analysis indicated that the PTEN protein was unstable, hydrophilic and nuclear localization, with multiple putative phosphorylation sites and a high degree of similarity to duck and goose PTEN. Moreover, PTEN exhibited high expression levels in various tissues such as the stomach, cecum, small intestine, spleen, thymus, harderian gland, muscle, cerebrum, cerebellum, lung, and liver in comparison to heart tissue. Overexpression of PTEN resulted in a significant promotion of the expression level of pro-apoptosis genes and inflammatory mediators, as well as the production of NO, with or without APEC infection, which led to cellular injury. Furthermore, overexpression of PTEN was found to regulate the expression levels of autophagy related genes, regardless of APEC infection. Additionally, PTEN was a target gene of gga-miR-20a-5p and regulated by gga-miR-20a-5p upon APEC infection. Taken together, these findings establish a foundation for investigating the biological function of chicken PTEN, providing a potential target for future treatments against APEC infection as well as the breeding of genetically resistant poultry.

Glutamine in ovo - Effects on the development and health of the gastrointestinal tract, antioxidant status and immune response in chickens

Glutamine in ovo - Effects on the development and health of the gastrointestinal tract, antioxidant status and immune response in chickens

A Marek's Disease Virus Messenger RNA-Based Vaccine Modulates Local and Systemic Immune Responses in Chickens.

Marek's disease (MD), caused by the Marek's disease virus, is a lymphoproliferative disease in chickens that can be controlled by vaccination. However, the current vaccines can limit tumor growth and death but not virus replication and transmission. The present study aimed to evaluate host responses following intramuscular injection of an mRNA vaccine encoding gB and pp38 proteins of the MDV within the first 36 h. The vaccine was injected in low and high doses using prime and prime-boost strategies. The expression of type I and II interferons (IFNs), a panel of interferon-stimulated genes, and two key antiviral cytokines, IL-1β and IL-2, were measured in spleen and lungs after vaccination. The transcriptional analysis of the above genes showed significant increases in the expression of MDA5, Myd88, IFN-α, IFN-β, IFN-γ, IRF7, OAS, Mx1, and IL-2 in both the spleen and lungs within the first 36 h of immunization. Secondary immunization increased expression of all the above genes in the lungs. In contrast, only IFN-γ, MDA5, MyD88, Mx1, and OAS showed significant upregulation in the spleen after the secondary immunization. This study shows that two doses of the MDV mRNA vaccine encoding gB and pp38 antigens activate innate and adaptive responses and induce an antiviral state in chickens.

A Whole Blood Method for Assessing the Innate Immune Response in Chickens

Innate immunity is considered the first line of immune defense and is typically an unmeasured response. Here we report a method for evaluating the innate immune response in chickens by using whole blood which has been activated by lipopolysaccharide (LPS) to induce IL-6 release by innate immune cells. It was found that a 24-h LPS activation time interval was the optimum time interval for inducing the IL-6 response. An activation index, defined as the PBS activated control response subtracted from the LPS activated response and then divided by the PBS activated control response and expressed as a percentage, was useful for demonstrating and comparing the magnitude of the innate immune response. Results indicated that there was wide variation between the IL-6 response between individual birds although statistically significant results were obtained for all individual birds at the 24-h activation time interval. The activation indices from all birds were greatest at the 24-h activation time interval. Statistically significant results were achieved when all the data from all birds at the 24-h activation time interval were combined. The cells responsible for the IL-6 response were identified as the peripheral blood monocytes.

Transcriptomic analysis uncovers a biphasic response to precocious Eimeria acervulina infection in chicken duodenal tissue

Live anticoccidial vaccines, either formulated with unattenuated or attenuated Eimeria parasites, are powerful stimulators of chicken intestinal immunity. Little is known about the dynamics of gene expression and the corresponding biological processes of chicken responses against infection with precocious line (PL) of Eimeria parasites. In the present study, we performed a time-series transcriptomic analysis of chicken duodenum across 15 time points from 6 to 156 hours post-infection (p.i.) with PL of E. acervulina. A high-quality profile showing two distinct changes in chicken duodenum mRNA expression was generated during the infection of Eimeria. Early response revealed that activation of the chicken immune response was detectable from 6 h.p.i., prominent genes triggered during the initiation of asexual and sexual parasite growth encompass immune regulatory effects, such as interferon gamma (IFN-γ), interferon regulatory factor 1 (IRF1), and interleukin-10 (IL10). The late response was identified significantly associating with maintaining cellular structure and activating lipid metabolic pathways. These analyses provide a detailed depiction of the biological response landscape in chickens infected by the PL of E. acervulina, contributing significant insights for the investigation of the host-parasite interactions and the management of parasitic diseases.

Feeding a Novel Mannan-Rich Yeast Carbohydrate Product Improves Production Performance and Humoral Immunity of Broiler Chickens.

The current study examined the benefits of a novel mannan-rich yeast carbohydrate product (YM) on broiler chicken growth performance and immune response against sheep red blood cells (SRBCs). A total of 144 newly hatched male Cornish cross broiler chicks were randomly assigned to four treatments with 12 cages per treatment and three birds per cage. The treatments were (1) control, basal diet; (2) YCW, basal diet + 1 g/kg yeast cell wall; (3) YM1, basal diet + 0.5 g/kg of a novel yeast mannan-rich product (YM); and (4) YM2, basal diet + 1 g/kg YM. Growth performance was measured at 14, 28, and 35 days of age (d). At 26 and 27 d, nine birds per treatment were immunized intravenously with SRBCs, and antibody responses against SRBCs were analyzed through a hemagglutination assay 7 days post-inoculation. Supplementing YM tended to improve broiler chicken weight gain from 29 to 35 d (p = 0.053). An improvement in the feed conversion ratio (FCR) was observed in the birds fed YM diets during 29-35 d and over the entire experimental period (0-35 d; p < 0.05). Furthermore, birds fed YM2 diets had more robust antibody responses against SRBCs than the control birds (p = 0.033). In conclusion, dietary supplementation of YM improved broiler chicken growth performance and antibody response against SRBCs.

FdeC expression regulates motility and adhesion of the avian pathogenic Escherichia coli strain IMT5155

Adaptation of avian pathogenic E. coli (APEC) to changing host environments including virulence factors expression is vital for disease progression. FdeC is an autotransporter adhesin that plays a role in uropathogenic Escherichia coli (UPEC) adhesion to epithelial cells. Expression of fdeC is known to be regulated by environmental conditions in UPEC and Shiga toxin-producing E. coli (STEC). The observation in a previous study that an APEC strain IMT5155 in which the fdeC gene was disrupted by a transposon insertion resulted in elevated adhesion to chicken intestinal cells prompted us to further explore the role of fdeC in infection. We found that the fdeC gene prevalence and FdeC variant prevalence differed between APEC and nonpathogenic E. coli genomes. Expression of the fdeC gene was induced at host body temperature, an infection relevant condition. Disruption of fdeC resulted in greater adhesion to CHIC-8E11 cells and increased motility at 42 °C compared to wild type (WT) and higher expression of multiple transporter proteins that increased inorganic ion export. Increased motility may be related to increased inorganic ion export since this resulted in downregulation of YbjN, a protein known to supress motility. Inactivation of fdeC in APEC strain IMT5155 resulted in a weaker immune response in chickens compared to WT in experimental infections. Our findings suggest that FdeC is upregulated in the host and contributes to interactions with the host by down-modulating motility during colonization. A thorough understanding of the regulation and function of FdeC could provide novel insights into E. coli pathogenesis.

A low-endotoxic Salmonella enterica Gallinarum serovar delivers infectious bronchitis virus immunogens via a dual-promoter vector system that drives protective immune responses through MHC class-I and -II activation in chickens

An effective vaccine strategy is indispensable against infectious bronchitis virus (IBV) and fowl typhoid (FT), both of which threaten the poultry industry. This study demonstrates a vector system, pJHL270, designed to express antigens in prokaryotic and eukaryotic cells. The vector system stimulates immune responses via synchronized antigen presentation to MHC class-I and -II molecules to produce balanced Th1/Th2 responses. The vaccine antigens were crafted by selecting the consensus sequence of the N-terminal domain of the spike protein (S1-NTD) and a conserved immunogenic region of the nucleocapsid protein (N321-406 aa) from IBV strains circulating in South Korea. The vaccine antigen was cloned and transformed into a live-attenuated Salmonella Gallinarum (SG) strain, JOL2854 (∆lon, ∆cpxR, ∆rfaL, ∆pagL, ∆asd). Western blot analysis confirmed concurrent antigen expression in Salmonella and eukaryotic cells. Oral immunization with the SG-based IBV vaccine construct JOL2918 induced IBV antigen and Salmonella-specific humoral and cell-mediated immune responses in chickens. PBMCs collected from immunized chickens revealed that MHC class-I and -II expression had increased 3.3-fold and 2.5-fold, respectively, confirming MHC activation via bilateral antigen expression and presentation. Immunization induced neutralizing antibodies (NAbs) and reduced the viral load by 2-fold and 2.5-fold in the trachea and lungs, respectively. The immunized chickens exhibited multifaceted humoral, mucosal, and cell-mediated responses via parallel MHC class-I and -II activation as proof of a balanced Th1/Th2 immune response. The level of NAbs, viral load, and gross and histological analyses provide clear evidence that the construct provides protection against IBV and FT.

MiR-214-PTEN pathway is a potential mechanism for stress-induced immunosuppression affecting chicken immune response to avian influenza virus vaccine

Stress-induced immunosuppression (SIIS) is one of common problems in the intensive poultry industry, affecting the effect of vaccine immunization and leading to high incidences of diseases. In this study, the expression characteristics and regulatory mechanisms of miR-214 in the processes of SIIS and its influence on the immune response to avian influenza virus (AIV) vaccine in chicken were explored. The qRT-PCR results showed that serum circulating miR-214 was significantly differentially expressed (especially on 2, 5, and 28 days post immunization (dpi)) in the processes, so had the potential as a molecular marker. MiR-214 expressions from multiple tissues were closely associated with the changes in circulating miR-214 expression levels. MiR-214-PTEN regulatory network was a potential key regulatory mechanism for the heart, bursa of Fabricius, and glandular stomach to participate in the process of SIIS affecting AIV immune response. This study can provide references for further understanding of stress affecting immune response.

Treatment of chickens with lactobacilli prior to challenge with Clostridium perfringens modifies innate responses and gut morphology

Necrotic enteritis caused by Clostridium perfringens (CP), is a common enteric disease of poultry that has been previously controlled by in-feed antibiotics. However, due to the rapid emergence of antimicrobial resistance, alternatives to antibiotics such as probiotics have received considerable attention because of their immunomodulatory and intestinal health benefits. The present study investigated the effects of probiotic lactobacilli on gut histomorphology and intestinal innate responses in chickens. Day-old male broiler chickens were treated with 1 × 107 or 1 × 108 colony-forming units (CFU) of a lactobacilli cocktail on days 1, 7, 14, and 20 post-hatch, while control groups were not treated with lactobacilli. On day 21, birds in all groups (except the negative control) were challenged with 3 × 108 CFU of CP for 3 days. Intestinal tissue samples were collected before and after the CP challenge to assess gene expression and for histomorphological analysis. Lactobacilli treatment at a dose of 1 × 108 CFU conferred partial protection against NE by lowering lesion scores, increasing villus height in the ileum and reducing crypt depth in the jejunum. In addition, 1 × 108 CFU of lactobacilli enhanced the expression of Toll-like receptor (TLR) 2, interferon-gamma (IFN-γ), interleukin (IL)-10, IL-12, and IL-13 in both the jejunum and ileum at different timepoints and subsequently decreased the expression of transforming growth factor beta (TGF-β) and IL-1β post-CP challenge. In conclusion, the results indicate that treatment with lactobacilli mitigated NE in a dose-dependent manner via improvement of intestinal morphology and modulation of innate immune response in chickens.

A preliminary study of the immunogenic response of plant-derived multi-epitopic peptide vaccine candidate of Mycoplasma gallisepticum in chickens.

Mycoplasma gallisepticum (MG) is responsible for chronic respiratory disease in avian species, characterized by symptoms like respiratory rales and coughing. Existing vaccines for MG have limited efficacy and require multiple doses. Certain MG cytoadherence proteins (GapA, CrmA, PlpA, and Hlp3) play a crucial role in the pathogen's respiratory tract colonization and infection. Plant-based proteins and therapeutics have gained attention due to their safety and efficiency. In this study, we designed a 21.4-kDa multi-epitope peptide vaccine (MEPV) using immunogenic segments from cytoadherence proteins. The MEPV's effectiveness was verified through computational simulations. We then cloned the MEPV, introduced it into the plant expression vector pSiM24-eGFP, and expressed it in Nicotiana benthamiana leaves. The plant-produced MEPV proved to be immunogenic when administered intramuscularly to chickens. It significantly boosted the production of immunoglobulin Y (IgY)-neutralizing antibodies against cytoadherence protein epitopes in immunized chickens compared to that in the control group. This preliminary investigation demonstrates that the plant-derived MEPV is effective in triggering an immune response in chickens. To establish an efficient poultry health management system and ensure the sustainability of the poultry industry, further research is needed to develop avian vaccines using plant biotechnology.

Multivalent DNA vaccine expressing the glycoproteins and tegument protein of infectious laryngotracheitis virus elicits robust humoral and cellular immune response in chickens

Multivalent DNA vaccine expressing the glycoproteins and tegument protein of infectious laryngotracheitis virus elicits robust humoral and cellular immune response in chickens

Silica-Calcite Sedimentary Rock (Opoka) Enhances the Immunological Status and Improves the Growth Rate in Broilers Exposed to Ochratoxin A in Feed.

Mycotoxins, such as Ochratoxin A (OTA), originating from fungi like Aspergillus and Penicillium, represent serious health hazards to poultry. The use of mycotoxin-adsorbing feed additives can reduce these risks. Opoka, a porous transitional rock, shows promise as one of these additives. This study is the first to examine the effect of Opoka administered with OTA on zootechnical parameters and the immune response of chickens. A 42-day investigation examined the impact of 1% of Opoka supplementation in feed on OTA-challenged broiler chickens. Seventy-two chickens were allocated into three groups of twenty-four individuals each: a control group, an OTA-exposed (2 mg/kg feed) group, and an OTA (2 mg/kg feed) plus 1% of Opoka group. Growth and blood parameters were monitored at predetermined intervals, and comprehensive biochemical, hematological, and cytometric analyses were conducted. The study showed that OTA exposure had a negative impact on chicken weight gain. However, adding Opoka to the diet improved weight gain, indicating its potential as a protective agent. Chickens fed with Opoka also had an increased white blood cell count, which suggests an improved immune response and elevated glucose and cholesterol concentrations. These findings indicate that Opoka may be useful in mitigating health complications caused by OTA exposure in broilers.

Yolkin, a Polypeptide Complex from Egg Yolk, Affects Cytokine Levels and Leukocyte Populations in Broiler Chicken Blood and Lymphoid Organs after In Ovo Administration.

Yolkin is a polypeptide complex isolated from hen egg yolk that exhibits immunomodulating properties. The aim of the present study was to determine whether in-ovo-delivered yolkin affects leukocyte populations and cytokine levels in broiler chickens. The experiment was carried out on eggs from Ross 308 broiler breeder birds. Yolkin was administered in ovo on the 18th day of incubation, once, at the following three doses: 1, 10, or 100 µg/egg. The immunological parameters were assessed in 1-, 7-, 14-, 21-, 28-, 35-, and 42-day-old birds kept under farming conditions and routinely vaccinated. The leukocyte populations were determined in the thymus, spleen, and blood. The cytokine (IL-1β, IL-2, IL-6, and IL-10) levels were determined in the plasma of the broiler chickens. Each experimental group included eight birds. The most pronounced effect of yolkin was an increase in the population of T cells, both CD4+ and CD8+, mainly in the blood. This effect on the lymphocyte subsets may be valuable regarding chicken immune responses, mainly against T-dependent antigens, during infection or after vaccination.

Chicken miR-148a-3p regulates immune responses against AIV by targeting the MAPK signalling pathway and IFN-γ

MicroRNAs are involved in the immune systems of host animals and play essential roles in several immune-related pathways. In the current study, we investigated the systemic biological function of the chicken miRNA gga-miR-148a-3p on immune responses in chicken lines resistant and susceptible to HPAIV-H5N1. We found that gga-miR-148a expression in the lung tissue of H5N1-resistant chickens was significantly downregulated during HPAIV-H5N1 infection. Overexpression of gga-miR-148a and a reporter construct with wild type or mutant IFN-γ, MAPK11, and TGF-β2 3′ untranslated region (3′ UTR)-luciferase in chicken fibroblasts showed that gga-miR-148a acted as a direct translational repressor of IFN-γ, MAPK11, and TGF-β2 by targeting their 3′ UTRs. Furthermore, miR-148a directly and negatively influenced the expression of signalling molecules related to the MAPK signalling pathway, including MAPK11, TGF-β2, and Jun, and regulated antiviral responses through interferon-stimulated genes and MHC class I and class II genes by targeting IFN-γ. Downstream of the MAPK signalling pathway, several proinflammatory cytokines such as IL-1β, IFN-γ, IL-6, TNF-α, IFN-β, and interferon-stimulated genes were downregulated by the overexpression of gga-miR-148a. Our data suggest that gga-miR-148a-3p is an important regulator of the MAPK signalling pathway and antiviral response. These findings improve our understanding of the biological functions of gga-miR-148a-3p, the mechanisms underlying the MAPK signalling pathway, and the antiviral response to HPAIV-H5N1 infection in chickens as well as the role of gga-miR-148a-3p in improving the overall performance of chicken immune responses for breeding disease-resistant chickens.

The efficacy of some probiotics and prebiotics on the prevalence of E. coli and the immune response of chickens

The present study aimed to investigate the efficacy of probiotics and prebiotics in controlling Escherichia coli (E. coli) spp. isolated from chicken. A total of 230 birds representing 19 different commercial breeds were taken from various points. Birds were monitored for postmortem and clinical investigation. Aseptically collected liver samples, lungs, kidneys, hearts, and yolk sacs were then subjected to bacterial isolation and identification. E. coli were observed in 9 pooled samples from 120 examined with an incidence of 7.5%. Nine farms were E. coli-positive, with an incidence of farm infection of 47.3%. The 9 suspected isolates of E. coli were profiled by morphological and microbiological identification of the colony, motility, and gram reaction. The serogroup analysis showed 9 different E. coli for which 3 other groups were identified: 2 E. coli O78, 3 E. coli O111, and 4 untyped groups. Nine isolates of E. coli were subjected to PCR. Molecular detection of 9 strains was conducted to find the virulence genes of E. coli strains (8 STX1, 4 STX2, and 9 EAE). Probiotics and prebiotics significantly increased the total erythrocytic and leukocytic counts throughout the experiment. The phagocytic percentage's main values at 14 d were 47 and 30%, respectively. An increase in the humoral immunity against Newcastle disease (ND) was noticed after ND vaccination. The geometric mean (HI) was 5.9 and 4.2 for probiotic and prebiotic, respectively. It could be concluded that probiotics and prebiotics could stimulate a nonspecific immune response against experimental infection with a virulent strain of E. coli spp.