Infectious Bronchitis Virus Antibodies Research Articles

Seroprevalence and molecular characterisation of infectious bronchitis virus (IBV) in broiler farms in Sabah, Malaysia.

Infectious bronchitis virus (IBV) is classified as a highly contagious viral agent that causes acute respiratory, reproductive and renal system pathology in affected poultry farms. Molecular and serological investigations are crucial for the accurate diagnosis and management of IBV. The purpose of this study was to determine the seroprevalence of IBV and to characterise the circulating IBV in poultry farms in Sabah Province, Malaysia. To determine IBV antibodies, a total of 138 blood samples and 50 organ samples were collected from 10 commercial broiler flocks in 3 different farms by using the enzyme-linked immunosorbent assay (ELISA) (IDEXX Kit) and reverse transcription-polymerase chain reaction (RT-PCR) followed by sequencing. A total of 94.2% (130/138) of the samples were seropositive for IBV in the vaccinated flock, and 38% (52/138) of the birds was the IBV titre for infection. The selected seropositive samples for IBV were confirmed by RT-PCR, with 22% (11/50) being IBV positive amplified and sequenced by targeted highly conserved partial nucleocapsid (N) genes. Subsequently, phylogenetic analysis constructed using amplified sequences again exposed the presence of Connecticut, Massachusetts, and Chinese QX variants circulating in poultry farms in Sabah, Malaysia. The unexpectedly increasing mean titres in serology indicated that post infection of IBV and highly prevalent IBV in selected farms in this study. The sequencing and phylogenetic analysis revealed the presence of multiple IBV variants circulating in Malaysian chicken farms in Sabah, which further monitoring of genetic variation are needed to better understand the genetic diversity.

A novel S2-derived peptide-based ELISA for broad detection of antibody against infectious bronchitis virus

Avian infectious bronchitis (IB) is a highly contagious disease caused by infectious bronchitis virus (IBV). Vaccination is an effective approach for controlling IBV. Therefore, reliable immune monitoring for IB is critical for poultry. In this study, a novel peptide derived from S2 protein was used to develop an enzyme-linked immunosorbent assay (ELISA) for the detection of broadly cross-reactive antibodies against IBV. The peptide-based ELISA (pELISA) showed good specificity and sensitivity in detecting IBV antibodies against different serotypes. A semilogarithmic regression method for determining IBV antibody titers was also established. Antibody titers detected by pELISA and calculated with this equation were statistically similar to those evaluated by indirect fluorescence assay (IFA). Moreover, the comparison analysis showed a 96.07% compatibility between the pELISA and IDEXX ELISA. All these data demonstrate that the pELISA generated here can be as a rapid and reliable serological surveillance tool for monitoring IBV infection or vaccination.

Seroprevalence of Infectious Bronchitis Virus in Broiler and Layer Farms of Central Ethiopia.

Background Infectious bronchitis virus (IBV) is a highly contagious viral disease of chicken typically affecting the reproductive and respiratory tract and results in possible economic causes from its serious infectious and transmission characteristics. Methods A cross-sectional study was carried on serum samples of chickens selected from six (two commercial and four small holder) farms and two types of production (broiler and layer) to detect seroprevalence of IBV and its associated risk factors in Bishoftu and Holeta areas of central Ethiopia from June 2021 to September 2021. A total of 354 blood samples were collected and subjected to indirect ELISA test by IBV antibody test kit ((ProFLOK IBV), from ProFLOK Laboratories Inc., (USA)) to detect specific antibodies against IBV. Results Overall, 97.46% seroprevalence was identified. From 230 and 124 samples collected from commercial and smallholder poultry farms, 226 (98.26%) and 119 (95.98%) positive results were obtained, respectively. Among the production types of chickens, high seroprevalence (99.31%) was found in layer poultry, and lower seroprevalence (96.17%) was found in the case of broiler chicken. Significant association was observed among different associated risk factors particularly age, sex, breed, and production types of chickens. From the tested chickens, all age groups, species, and farm types have high seroprevalence of IBV. The prevalence of IBV was highly significant (p ≤ 0.01) in the study site. The risk factors indicated could have increased infection prevalence, pathogens' economic impact, and disease occurrence. Conclusion IBD is complicating factor affecting poultry production systems in the area. Vaccine and biosecurity measures are recommended for the control of IBV. Furtherly, identification and characterization (by using RT-PCR) of persistent serotype of IBV circulating in the field are recommended.

Multiple antigenic peptide-based flow through dot-blot assay for simultaneous antibody detection of infectious bronchitis virus and Newcastle disease virus

The present study describes the development of a novel affordable and rapid visual dot-blot assay using synthetic multiple antigenic peptides (MAP) for simultaneous detection of antibodies to infectious bronchitis virus (IBV) and Newcastle disease virus (NDV). Antibody detection efficiencies of MAP peptides namely, NP1 MAP (Nucleoprotein IBV) and HN MAP (Haemagglutinin-neuraminidase NDV) were studied in solid-phase indirect peptide ELISA. In comparison with the commercial kit, the NP1 MAP showed 89.20% diagnostic sensitivity (DSn) and 85.90% diagnostic specificity (DSp) at 19.45% ROC cut-off. Similarly, HN MAP was evaluated and showed 89.70% DSn and 92.90% DSp at 19.90 % ROC cut-off. The peptides after evaluating their ELISA performance were further used to device a flow-through dot-blot assay (FT-DBA) for simultaneous detection of IBV and NDV antibodies. The kappa value for IBV by FT-DBA in comparison to commercial ELISA was 0.64 whereas for NDV, FT-DBA gave a kappa value of 0.68 in comparison to commercial ELISA indicating substantial agreement between the assays. In essence, the divergent MAP based diagnostic design could provide an alternative for antibody detection of IBV and NDV. Further, the FT-DBA approach could be used for low cost, rapid and pen-side detection of IBV and NDV antibodies simultaneously.

Development and application of a novel triplex protein microarray method for rapid detection of antibodies against avian influenza virus, Newcastle disease virus, and avian infectious bronchitis virus.

Avian influenza virus (AIV), Newcastle disease virus (NDV), and avian infectious bronchitis virus (IBV) inflict immense damage on the global poultry industry annually. Serological diagnostic methods are fundamental for the effective control and prevention of outbreaks caused by these viruses. In this study, a novel triplex protein microarray assay was developed and validated for the rapid and simultaneous visualized detection of antibodies against AIV, NDV, and IBV in chicken sera. The AIV nuclear protein (NP), NDV phosphoprotein (P), and IBV nonstructural protein 5 (nsp5) were produced in a prokaryotic expression system, purified, and immobilized onto an initiator integrated poly(dimethylsiloxane) (iPDMS) film as probes to detect antibodies against these viruses in chicken sera. After optimization of the reaction conditions, no cross-reactivity was detected with infectious bursal disease virus, avian leukosis virus subgroup J and chicken anemia virus antisera. The lowest detectable antibody titers in this assay corresponded to hemagglutination inhibition (HI) titers of 24 and 21 for AIV and NDV, respectively, and to an IDEXX antibody titer of 103 for IBV, using the HI assay and IDEXX commercial ELISA kit as the reference methods. When156 serum samples were tested using the new assay, the HI test and the IBV IDEXX ELISA kit, the assay showed 96.8% (151/156), 97.4% (152/156) and 99.4% (155/156) diagnostic accuracy for detection of AIV, NDV and IBV antibody, respectively. The current study suggests that the newly developed triplex microarray is rapid, sensitive, and specific, providing a viable alternative assay for AIV, NDV, and IBV antibody screening in epidemiological investigations and vaccination evaluations.

A Peptide-Based Enzyme-Linked Immunosorbent Assay for Detecting Antibodies Against Avian Infectious Bronchitis Virus.

Infectious bronchitis virus (IBV) causes substantial loss to the poultry industry despite extensive vaccination. Assessing the antibody response is important for the development and evaluation of effective vaccines. We have developed an enzyme-linked immunosorbent assay (ELISA) for the detection of IBV-specific antibodies, using a synthetic peptide based on a conserved sequence in the IBV spike protein. This peptide-based ELISA (pELISA) specifically detects antibodies to different genotypes of IBV but not antibodies against other common chicken viruses. This assay could detect IBV-specific antibody response on as early as day 7 postinfection. In the testing with field serum samples collected from chickens administered with IBV vaccines, the sensitivity, specificity, and accuracy of pELISA were 98.30, 94.12, and 98.8%, respectively, relative to indirect immunofluorescence assay. Our data demonstrate that the pELISA is of value for the detection of IBV antibody and the evaluation of IBV vaccines.

A bio-safe multiple antigenic peptide (MAP) enzyme-linked immunoassay for the detection of antibodies to infectious bronchitis virus in chickens.

The objective of the study was to develop a bio-safe synthetic peptide ELISA for the detection of antibodies against the infectious bronchitis virus (IBV) using a novel multiple antigenic peptide approach (MAP). After initial ELISA optimization, diagnostic sensitivity (DSn) and specificity (DSp) for the linear peptides were determined using receiver operator curve (ROC) analysis. The peptide IBVP1 showed 90.44% DSn and 88.64% DSp at ROC cut off 22.8% while IBVP2 showed 88.24% DSn and 85.23% DSp at ROC cut off 23.05%. The multimerization of linear peptides to MAP design resulted in the improvement of the diagnostic efficiency up to 94.85% DSn and 92.05% DSp for IBVM1 with 19.95% cut off. A similar improvement in the performance was also observed with 92.65% DSn and 90.91% DSp for IBVM2 at 20.72% cut off. All the peptides were tested for diagnostic specificity and did not show the cross-reactivity with Newcastle disease virus and infectious bursal disease virus positive serum samples. In addition, repeatability testing for all linear and multimeric peptide showed that the coefficient of variation for intra-assay was within the expected limits, ranging from 2.4 to 10.4% and inter-assay coefficient of variation was ranging from 5.56 to 14.3%. In a nutshell, the present study used predicted B cell epitope, the synthetic peptide in linear and multimeric design for IBV antibody detection. The study also highlights peptide antigen with modified scaffold design could be a safe alternative to whole virion-based ELISA for IBV antibody detection.

Construction and Immunogenicity of Novel Chimeric Virus-Like Particles Bearing Antigens of Infectious Bronchitis Virus and Newcastle Disease Virus.

Infectious bronchitis virus (IBV) and Newcastle disease virus (NDV) are two poultry pathogens seriously affecting the poultry industry. Here, IBV S1 and the ectodomain of NDV F proteins were separately linked with the trans-membrane and carboxy-terminal domain of IBV S protein (STMCT), composing rS and rF; thus, a novel chimeric infectious bronchitis-Newcastle disease (IB-ND) virus-like particles (VLPs) vaccine containing the rS, rF, and IBV M protein was constructed. Under the transmission electron microscope (TEM), VLPs possessing similar morphology to natural IBV were observed. To evaluate the immunogenicity of chimeric IB-ND VLPs, specific pathogen-free (SPF) chickens were immunized with three increasing doses (50, 75, and 100 μg protein of VLPs). Results of ELISAs detecting IBV and NDV specific antibodies and IL-4 and IFN-γ T cell cytokines indicated that vaccination with chimeric IB-ND VLPs could efficiently induce humoral and cellular immune responses. In the challenge study, chimeric IB-ND VLPs (100 μg protein) provided 100% protection against IBV or NDV virulent challenge from death, and viral RNA levels in tissues and swabs were greatly reduced. Collectively, chimeric IB-ND VLPs are highly immunogenic and could provide complete protection from an IBV or NDV virulent challenge. Chimeric IB-ND VLPs are an appealing vaccine candidate and a promising vaccine platform bearing multivalent antigens.

Early Vaccination of Chickens Induces Suboptimal Immunity Against Infectious Bronchitis Virus

Infectious bronchitis virus (IBV) is highly prevalent in broiler chickens despite extensive vaccination commonly conducted early after hatch. The effects of early vaccination on immune responses were further investigated in chickens primed at increasing ages, followed by booster vaccination with an attenuated Arkansas (Ark) Delmarva Poultry Industry-type vaccine. Results show that vaccination on day 1 of age elicits significantly lower systemic and mucosal antibody responses compared with vaccination at later time points in the life of the chicken. The increase of IBV antibodies in serum from secondary responses after booster vaccination was more dramatic and significantly higher when measured by an Ark spike subunit 1 protein ELISA compared with measuring by non-Ark serotype whole-virus ELISA, which underlines the immunogenic importance of the virus spike at inducing antibodies. However, the levels achieved following boosting did not differ significantly between ages of priming. Thus, it seems that the booster vaccination mitigated the differences detected after prime immunization. In contrast to the continued rise of systemic antibodies after booster vaccination, the levels of mucosal IBV-specific immunoglobulin A decreased after booster vaccination. The recruitment or expansion of cluster of differentiation (CD)4+, CD8+, and CD4+/CD8+ T-cell populations in different immune effector sites was increased with age, but remained unaltered by IBV vaccination. In contrast, peripheral blood CD4+ cells showed a significant increase in IBV-vaccinated chickens compared with nonvaccinated age-matched controls both after primary and booster immunization. The results of the current study confirm that IBV vaccination on the day of hatch induces suboptimal IBV immune responses both in the systemic and mucosal compartments. This routine practice may be contributing to the immunologic escape of the virus and increased persistence of vaccine virus in vaccinated chickens. However, booster vaccination seems to overcome poor initial responses.

Effects of dietary yeast nucleotides supplementation on intestinal barrier function, intestinal microbiota, and humoral immunity in specific pathogen-free chickens.

Yeast nucleotides are a fine functional additive in human and animals. The effects of dietary yeast nucleotides supplementation on intestinal development, expression of intestinal barrier-related genes, intestinal microbiota, and infectious bronchitis virus (IBV) antibody titer of specific pathogen-free (SPF) chickens were investigated. A total of 60 1-d-old chickens were divided into 4 groups, each of which included 3 replicates of 5 chickens. Group 1 served as a control that was fed a basal diet. Groups 2 to 4 were fed the basal diet supplemented with 0.1%, 0.3% and 0.5% yeast nucleotides, respectively. All chickens were inoculated intranasally with inactivated IBV vaccine at day 1 and day 10. At day 17, the intestinal development, expression of intestinal barrier-related genes and microbiota were evaluated. There was a significant increased ileal villus height and villus height to crypt depth ratio in group 2 (P < 0.05). Moreover, group 4 exhibited higher expression of zonula occludens-1 (ZO-1) and Occludin gene in ileum (P < 0.05), whereas groups 2 and 3 exhibited higher expression of Mucin 2 (MUC2) and trefoil factor 2 (TFF2) gene (P < 0.05), group 2 showed lower expression of IFN-α gene (P < 0.05). Dietary yeast nucleotides increased intestinal bacterial diversity (P < 0.05), and the abundance of Lactobacillus (P < 0.05). At day 10, 17, 24, 31, 38, and 45, the serum IBV antibody titers were tested. Group 2 exhibited higher IBV antibody titer at day 17 (P < 0.05), furthermore, groups 2 to 4 reached the effective levels 1 wk earlier than control group. In conclusion, dietary yeast nucleotides supplementation can help birds to mount a faster and stronger antibody response to IBV vaccine. In addition, dietary yeast nucleotides supplementation can also promote the intestinal development and barrier-related genes expression, and diversity and richness of intestinal microbiota.

Development of a sensitive and specific xMAP assay for detection of antibodies against infectious laryngotracheitis and bronchitis viruses

BackgroundA serological method to simultaneously detect antibodies against infectious laryngotracheitis virus (ILTV) and infectious bronchitis virus (IBV) is imperative for the differential diagnosis and evaluation of antibodies titers after vaccination.MethodThe microspheres coated with purified recombinant glycoprotein D (gD) of ILTV or nucleocapsid (N) protein of IBV were incubated with serum samples. The simultaneous quantification of ILTV and IBV antibodies were achieved through the interrogation of microspheres by Luminex 200 detection system. .ResultsThis xMAP detection demonstrated no nonspecific reactions with avian influenza virus (AIV), avian leukosis virus (ALV), newcastle disease virus (NDV), and Marek’s disease virus (MDV). The results also demonstrated that the xMAP assay was four times more sensitive than the enzyme-linked immunosorbent assay (ELISA) for ILTV detection and two times more sensitive for IBV detection. A total of 90 chicken serum samples from a chicken farm were tested by xMAP and ELISA assays. The results showed that the coincidence rates were 84.44 and 100% for ILTV and IBV detection, respectively.ConclusionThis study exhibited an opportunity for the differential diagnosis through simultaneous detection of multiplex antibodies in serum and can be used for the multiplex antibodies evaluation after vaccination.

Evaluation of the prevalence of viral bronchitis infection in broiler chicken by using ELISA Technique

The study was conducted to evaluate the seroprevalence of Infectious Bronchitis virus (IBV) in broiler chickens farms in Kirkuk Governorate. The technique has been used in the study, Enzyme Linked Immunosorbent Assay (ELISA). Nine hundred serum samples were collected from (10) broilers farms, During the period from April 2016 to May 2016, including (90) samples from (1) symptomatic, non-vaccinated broilers farms. (90) samples from one asymptomatic, vaccinated broilers farm, and another (630) samples from one asymptomatic, non-vaccinated broilers farm, the remaining (90) samples from one symptomatic, vaccinated broilers farms, and were tested for the presence of IBV antibodies by ELISA kit. One hundred and ninety six serum samples were positive ( %65.3 ) : 78/90 (86.6%) samples were symptomatic, non-vaccinated, another 63/90 (70%) were asymptomatic, vaccinated broilers farm, and 432/630 (68.5%) were asymptomatic, non-vaccinated broiler farm, the remaining 15/90 (16.6%) were symptomatic, vaccinated broilers farm. The remaining samples (312) were negative by ELISA.

EVALUATION OF THE IMMUNE RESPONSE OF SOME CHICKEN FARMS TO INFECTIOUS BRONCHITIS VIRUS IN AL-AHSA PROVINCE IN SAUDI ARABIA

Infectious bronchitis virus (IBV) still to pose great economic losses among chickens of all ages in many parts in the world. Despite the massive application of IBV vaccines in many countries including Saudi Arabia, several outbreaks are still frequently reported. One of the important challenges that hampered the selection of the right vaccine candidates is the identification of the local circulating strain in a certain area. IBV is recently reported in many chickens flocks in the Eastern region of the Kingdom. The major goals of our study were to evaluate the immune status of some chicken farms in Al-Ahsa to IBV. To achieve this goal, total of (368) serum samples- from chicken farms from Al-Ahsa region were collected. Our results showing high seroprevelance of IBV in the non-IBV vaccinated chicken farms suggesting their exposure to the natural IBV infection. Meanwhile, we were able to detect a high IBV antibody titers in vaccinated chicken farms suggesting the used vaccines induced detectable IBV antibodies. This suggesting the circulation of novel IBV strains in these chicken farms. The overall results confirm the circulating of novel IBV strains in chicken farms in Al-Ahsa region. Further studies are needed to do molecular characterization of these IBV strains

Development and application of nsp5-ELISA for the detection of antibody to infectious bronchitis virus

Infectious bronchitis virus (IBV) continues to be one of the most important poultry pathogens worldwide. The current commercially available enzyme-linked immunosorbent assay (ELISA) kits for IBV specific antibody detection are mostly based on the whole virion, and few serological tests based on nonstructural proteins of IBV have been developed. Herein, an alternative indirect ELISA for detection of IBV antibody was developed with IBV nonstructural protein 5 (nsp5) produced by Escherichia coli. Using an indirect immunofluorescence assay (IFA) and a commercial ELISA kit as reference, we optimized the nsp5-ELISA and determined its cut-off as 0.12. The diagnostic sensitivity (DSN), specificity (DSP) and accuracy of the nsp5-ELISA were 93.11%, 95.38% and 93.33%, respectively, compared with IFA in 660 field serum samples, and were 98.11%, 95.00% and 97.62%, respectively, compared with the commercial IBV ELISA kit (IDEXX) in 126 field sera samples. Furthermore, a time course of IBV specific antibody level detected by nsp5-ELISA following IBV infection and vaccination is consistent with that of IBV antibody detected by the commercial ELISA kit. The results presented in this study indicate that nsp5-ELISA has the potential to serve as a rapid, reliable and cost-effective method for IBV antibody detection. This study is the first to report the development of an nsp-based ELISA to detect an antibody to IBV.

Serological Evidence of Infectious Bronchitis Virus among Some Poultry Species in Maiduguri, Nigeria

A sero-prevalence study of Infectious Bronchitis Virus (IBV) among some species of poultry (village chickens, broilers, layers, turkeys, ducks and geese) in Maiduguri Metropolis was conducted using Enzyme linked immunosorbent assay. An overall prevalence of 26.6% was observed in the study. The species distribution of the positive samples showed 5/18 (27.8%) broilers, 9/48 (18.8%) village chicken, 12/40 (30%) turkeys, 4/29 (13.8%) ducks, 6/23 (26.1%) geese and 14/30 (46.7%) layers were sero-positive for IBV antibodies. The sex distribution of the IBV positive samples revealed significant difference (p

Molecular and serological study by using ELISA and rRT-PCR techniques to detect avian infectious bronchitis virus in chickens in Middle Euphrates

The study was conducted to detect Infectious Bronchitis Virus (IBV) in commercial chicken farms of Middle Euphrates, the technique have been used throughout the study protocol, Enzyme Linked Immunosorbent Assay (ELISA), Real Time Reverse Transcription Polymerase Chain Reaction (RT-PCR) and histopathological study. (172) serum samples were collected from clinically infected vaccinated broiler farm and (29) serum samples were collected from clinically infected non-vaccinated broiler farm, and screened for the presence of IBV antibodies by ELISA.75serum samples from 172 samples were positive ,(43.6%) distributed as followed 43 (61.4%) from Hella, 23 (36.5%) from Najaf and 9 (23.07%) from Diwaneyah ,29 serum samples collected from clinically infected non-vaccinated broiler flocks, were 5 (17.2%) serum positive samples for IBV. (75) tissue samples from clinically infected vaccinated broilers distributed were submitted for rRT-PCR technique, the results were as followed42 (56%) have been detected IBV, while 30 (71.4%) was positive in ELISA, and (15) samples from clinically infected non-vaccinated broilers showed 8 (53.3%) IBV were detectable while 5 (62.5%) was positive in ELISA. Also the research include study the histopathological changes of trachea, lung and kidney of infected birds which were positive for rRT-PCR.

Immunoglobulin A as an early humoral responder after mucosal avian coronavirus vaccination.

Infectious bronchitis virus (IBV) is a highly contagious coronavirus prevalent in all countries with an extensive poultry industry and continues to cause economic losses. IBV strains of the Ark serotype are highly prevalent in the Southeastern United States despite extensive vaccination. One explanation for this observation is the high genetic variability of IBV. In addition, IBV Ark-type vaccines may induce suboptimal mucosal immune responses, contributing to the prevalence and persistence of the Ark serotype. To test this hypothesis, chickens were ocularly vaccinated with a commercially available live attenuated IBV Ark-Delmarva Poultry Industry vaccine strain and both mucosal and systemic antibody responses were measured. The highest immunoglobulin A (IgA) spot-forming cell (SFC) response was observed in the Harderian glands (HG) and to a lesser extent in the spleen and conjunctiva-associated lymphoid tissues, while a limited IgG SFC response was observed in either the mucosal or systemic immune compartment. Interestingly, the peak IgA SFC response occurred 2 days earlier in spleen than in the head-associated lymphoid tissues despite ocular vaccination. Furthermore, IgA IBV-specific antibody levels significantly increased over controls 3 days earlier in tears and 4 days earlier in plasma than did IgG antibodies. IgA antibody levels were higher than IgG antibody levels throughout the primary response in tears and were similar in magnitude in plasma. In addition, a very early increase in IgA antibodies on day 3 postvaccination was observed in tears; such a response was not observed in plasma. This early increase is consistent with a mucosal T-independent IgA response to IBV. In the secondary response the IBV antibody levels significantly increased over controls starting on day 1 after boosting, and the IgG antibody levels were higher than the IgA antibody levels in both tears and plasma. In summary, ocular vaccination induced higher IgA antibodies in the primary IBV response, while the memory response is dominated by IgG antibodies. Thus, lower mucosal IgA antibody levels are observed upon secondary exposure to IBV, which may contribute to vulnerability of host epithelial cells to infection by IBV and persistence of the Ark serotype.

English

Infectious bronchitis (IB) is one of the devastating chicken viral diseases that causes significant financial loses to chicken industry worldwide. In this study, highly purified recombinant nucleocapsid protein (rNP) of IB virus (IBV) was used to develop an in-house enzyme linked immunosorbent assay (iELISA) for the detection of IB. The iELISA was optimized to achieve maximum sensitivity and specificity. All tested broiler chicken farms were positive for IBV antibody in a commercial ELISA kit (cELISA) and the optimized iELISA. Thirty three (33) specific pathogen free (SPF) chickens and 20 broiler chickens held in a restricted environment tested negative for IBV antibody in both ELISA. The above results suggest that the iELISA is a sensitive and specific test for the detection of antibody to IBV in chicken flocks. &nbsp; Key words:&nbsp;Enzyme linked immunosorbent assay (ELISA), infectious bronchitis (IB), recombinant nucleocapsid protein (rNP).

Ameliorative effect of a microbial feed additive on infectious bronchitis virus antibody titer and stress index in broiler chicks fed deoxynivalenol

Although acute mycotoxicoses are rare in poultry production, chronic exposure to low levels of mycotoxins is responsible for reduced productivity and increased susceptibility to infectious diseases. Deoxynivalenol (DON) is known to modulate immune function, but only a few studies have investigated the effect of DON on the vaccinal immune response. In addition, the effects of Mycofix select (Biomin GmbH, Herzogenburg, Austria) supplementation to DON-contaminated broiler diets have not yet been demonstrated. Therefore, an experiment with 1-d-old male broilers (Ross 308) was carried out to examine the effects of feeding DON-contaminated low-protein grower diets on performance, serum biochemical parameters, lymphoid organ weight, and antibody titers to infectious bronchitis vaccination in serum and to evaluate the effects of Mycofix select dietary supplementation in either the presence or absence of DON in broilers. In total, thirty-two 1-d-old broiler chicks were randomly assigned to 1 of the 4 dietary treatments for 5 wk. The dietary treatments were 1) control; 2) artificially contaminated diets with 10 mg of DON/kg of diet; 3) DON-contaminated diets supplemented with Mycofix select; and 4) control diet supplemented with Mycofix select. Feeding of contaminated diets decreased (P = 0.000) the feed intake, BW (P = 0.001), BW gain (P = 0.044), and feed efficiency during the grower phase. Deoxynivalenol affected the blood biochemistry, whereas plasma total protein and uric acid concentrations in birds fed contaminated grains were decreased compared with those of the controls. Moreover, in birds fed contaminated feeds, there was a tendency to reduce triglycerides in the plasma (P = 0.090), suggesting that DON in the diets affected protein and lipid metabolism in broiler chickens. The feeding of contaminated diets altered the immune response in broilers by reducing the total lymphocyte count. Similarly, the antibody response against infectious bronchitis vaccination antigens was decreased (P = 0.003) after feeding contaminated diets, compared with the controls. Moreover, contamination of the broiler diet with DON increased the heteropil:lymphocyte ratio (stress index), suggesting that DON elevated the physiological stress responses of broilers. However, feeding of DON-containing diets did not alter the other plasma constituents, including activities of enzymes. Mycofix select addition to the DON-contaminated feed led to normal immunological and physiological functions in broilers that were comparable with those of the control group, indicating that the addition of the additive to the DON-contaminated feed of the broilers effectively alleviated the alterations caused by DON. It was concluded that broiler performance and some blood and immunological parameters were adversely affected by feeding diets contaminated with the Fusarium mycotoxin DON. However, the dietary Mycofix select supplementation as a detoxifying agent was successful in overcoming the mycotoxin-related effects.

Effects of Chinese herbal formula Maxing Shigan powder on IgA secreting cells in chicken bronchus

In this paper the effects of a Chinese formula Maxing Shigan powder were investigated on IgA-secreting cells of chicken bronchus. The herbal powder was dissolved in water at three dosages, 0.5, 1 and 1.5 g/L. Each dosage was given to 15-day-old chickens which were challenged with infectious bronchitis virus (IBV) by artificial infection for 3 days. Then thetherapeutic effects were detected. The chickens were sacrificed at 18, 21, 24, 27 and 30 days old. The changes of IgA-secreting cells per unit area of bronchus were measured by immunohistochemistry. The IBV antibody titers in serum were determined by ELISA. The results of the therapeutic effects showed that Maxing Shigan powder can significantly reduce the mortality and enhance the recovery rate. Positive expression rate of bronchial IgA-secreting cells and higher IBV antibody titers were observed in the herbal treated groups. The results suggest that Maxing Shigan powder can protect the mucosa of IBV chickens, promote IgA secreting cells recruitment in the mucosa and secretion of the IBV antibody so as to lower the mortality and elevate the recovery rate of the IBV infected chickens. Key words: Maxing Shigan powder, infectious bronchitis virus, IgA secreting cells, antibody.In this paper the effects of a Chinese formula Maxing Shigan powder were investigated on IgA-secreting cells of chicken bronchus. The herbal powder was dissolved in water at three dosages, 0.5, 1 and 1.5 g/L. Each dosage was given to 15-day-old chickens which were challenged with infectious bronchitis virus (IBV) by artificial infection for 3 days. Then thetherapeutic effects were detected. The chickens were sacrificed at 18, 21, 24, 27 and 30 days old. The changes of IgA-secreting cells per unit area of bronchus were measured by immunohistochemistry. The IBV antibody titers in serum were determined by ELISA. The results of the therapeutic effects showed that Maxing Shigan powder can significantly reduce the mortality and enhance the recovery rate. Positive expression rate of bronchial IgA-secreting cells and higher IBV antibody titers were observed in the herbal treated groups. The results suggest that Maxing Shigan powder can protect the mucosa of IBV chickens, promote IgA secreting cells recruitment in the mucosa and secretion of the IBV antibody so as to lower the mortality and elevate the recovery rate of the IBV infected chickens. Key words: Maxing Shigan powder, infectious bronchitis virus, IgA secreting cells, antibody.