Newcastle Disease Vaccine Research Articles

Determination of immunogenicity of an inactivated ND-vaccine developed experimentally with Newcastle disease virus (Genotype VII.2) local isolates of Bangladesh

BackgroundNewcastle disease virus (NDV) genotype VII severely affects poultry, causing respiratory and neurological symptoms with a high rate of morbidity and mortality. The research aimed to develop an inactivated ND vaccine using local isolates (Genotype VII.2) and assess its immunogenicity compared to other commercial live ND vaccines.MethodsAn inactivated vaccine using a candidate NDV (GenBank: OR924274.1) was developed according to WOAH guidelines following inactivation, sterility, purity, and safety tests. The birds were vaccinated through subcutaneous (SC) and intramuscular (IM) routes using three doses (0.25, 0.5, and 1.0 ml/bird). Immunogenicity and protective potentiality of the experimentally developed inactivated ND vaccine and live commercial ND vaccine (intra-ocularly/IO) were compared by challenge studies using three vaccination schedules: killed-followed-killed, live-followed-killed, and live-followed-live.ResultsThe birds vaccinated with 1.0 ml/bird SC showed higher antibody titers compared to those of IM-vaccinated groups. Birds vaccinated with the live-followed-killed commercial ND vaccines had slightly higher antibody titers compared to those vaccinated with killed-followed-killed and live-followed-live vaccines. Birds vaccinated with the killed-followed-killed ND vaccine showed a higher protection rate (100%) compared to live-followed-killed (83±5.77%) and live-followed-live (57±5.77%) vaccines. Birds vaccinated with killed-followed-killed group showed a slower decline rate of antibody titers than other groups. This regimen provided significantly better immunity, highlighting its potential in controlling ND outbreaks in Bangladesh's poultry.ConclusionThe study found that the inactivated ND vaccine, developed with the locally circulating isolate of genotype-VII.2 of NDV, might play an important role in effective control and management of ND in the commercial poultry population in Bangladesh.

Development and Evaluation of a Novel Chimeric Genotype VII Newcastle Disease Vaccine: Overcoming Maternal Antibody Interference and Spray Administration

Newcastle disease virus (NDV) poses a significant threat to the poultry industry, with the emergence of genotype VII NDV leading to extensive outbreaks and economic losses. Vaccination is the primary means of controlling NDV, but the presence of maternal antibodies (MDAs) can interfere with the immunological effect of live virus vaccines. Thus, we constructed a chimeric NDV live virus vaccine, LX-OAI4S, by replacing the extracellular regions of the F and HN genes of the NDV LX strain with the corresponding regions of the A-VII vaccine strain. The chimeric vaccine LX-OAI4S demonstrated high genetic stability, good safety, and strong reproductive capacity in chicken embryos. The LX-OAI4S vaccine induced rapid antibody production in specific pathogen-free (SPF) and commercial chickens via the intranasal and intraocular (IN/IO) routes, with hemagglutination inhibition (HI) antibody titers reaching 4.71 ± 1.03 log2 at 7 days post-vaccination (dpv), significantly higher than those of the two classical vaccine strains La Sota and VG/GA. The LX-OAI4S vaccine group provided effective protection against the challenge of genotype VII NDV virulent strain JS2/06 and inhibited viral shedding. When administered via spray, the LX-OAI4S vaccine elicited high systemic immunity against NDV in both SPF and commercial chickens, effectively protecting against clinical disease and reducing viral shedding. The chickens were exposed to high-dose vaccine for spray vaccination, and no adverse reactions were observed after vaccination. Despite the presence of anti-NDV MDAs in chickens, the NDV-specific antibody titers were significantly greater in the vaccinated groups than in the unvaccinated group. The vaccine exhibited high immunogenicity and the potential to overcome maternal antibody interference. The LX-OAI4S vaccine is a promising candidate for an ND vaccine. Its administration via spray can effectively prevent the occurrence of ND, making it a valuable tool for the poultry industry.

Multi-Epitopic Peptide Vaccine Against Newcastle Disease Virus: Molecular Dynamics Simulation and Experimental Validation

Background: Newcastle disease virus (NDV) is a highly contagious and economically devastating pathogen affecting poultry worldwide, leading to significant losses in the poultry industry. Despite existing vaccines, outbreaks continue to occur, highlighting the need for more effective vaccination strategies. Developing a multi-epitopic peptide vaccine offers a promising approach to enhance protection against NDV. Objectives: Here, we aimed to design and evaluate a multi-epitopic vaccine against NDV using molecular dynamics (MD) simulation. Methodology: We retrieved NDV sequences for the fusion (F) protein and hemagglutinin–neuraminidase (HN) protein. Subsequently, B-cell and T-cell epitopes were predicted. The top potential epitopes were utilized to design the vaccine construct, which was subsequently docked against chicken TLR4 and MHC1 receptors to assess the immunological response. The resulting docked complex underwent a 1 microsecond (1000 ns) MD simulation. For experimental evaluation, the vaccine’s efficacy was assessed in mice and chickens using a controlled study design, where animals were randomly divided into groups receiving either a local ND vaccine or the peptide vaccine or a control treatment. Results: The 40 amino acid peptide vaccine demonstrated strong binding affinity and stability within the TLR4 and MHC1 receptor–peptide complexes. The root mean square deviation of peptide vaccine and TLR4 receptor showed rapid stabilization after an initial repositioning. The root mean square fluctuation revealed relatively low fluctuations (below 3 Å) for the TLR4 receptor, while the peptide exhibited higher fluctuations. The overall binding energy of the peptide vaccine with TLR4 and MHC1 receptors amounted to −15.7 kcal·mol−1 and −36.8 kcal·mol−1, respectively. For experimental evaluations in mice and chicken, the peptide vaccine was synthesized using services of GeneScript Biotech® (Singapore) PTE Limited. Experimental evaluations showed a significant immune response in both mice and chickens, with the vaccine eliciting robust antibody production, as evidenced by increasing HI titers over time. Statistical analysis was performed using an independent t-test with Type-II error to compare the groups, calculating the p-values to determine the significance of the immune response between different groups. Conclusions: Multi-epitopic peptide vaccine has demonstrated a good immunological response in natural hosts.

Association of Major Histocompatibility Complex Polymorphism With Acute Phase Response in Broiler Chicken.

Stress associated with changes in host immunity occurs in response to altered environmental conditions, endogenous imbalances, infectious agents and harmful stimuli. The importance of genetic diversity in chickens has increased due to individual immune differences towards resistance and susceptibility to various stimuli. This study aimed to investigate the association of major histocompatibility complex (MHC) polymorphism with acute phase response (APR) in Ross 308 broiler chickens. The allelic diversity of the LEI0258 microsatellite marker was determined in 120 Ross broilers. In addition, acute phase proteins (APPs), including serum amyloid A (SAA) and alpha-1-acid glycoprotein (AGP), were analysed as markers of the APR. Furthermore, leukocyte count and the heterophil/lymphocyte ratio (H/L ratio) were examined. The antibody response to the Newcastle disease vaccine (NDV) was also measured to assess humoral mediated immunity. Lastly, the correlation between immune responses and MHC alleles was investigated to identify the most effective alleles in a stress-related situation. A total of six alleles, ranging from 195 to 448bp, were identified. Association study revealed a significant influence of MHC alleles on APPs in Ross population (p<0.05). Notably, Allele 448 had a significant correlation with SAA concentration and the H/L ratio. Allele 207 displayed a positive association with AGP concentration, whereas Allele 195 showed a negative association. Furthermore, a significant association was observed between Allele 448 and basopenia, as well as between Allele 195 and monocytosis. Results confirmed the significance of MHC as a candidate gene marker for immune responses, which supports its use for vaccine design, genetic improvement of disease-resistant traits and resource conservation in commercial broiler chickens.

Effect of Probiotic, Prebiotic and/or Fosfomycin in Control of Drug-Sensitive and Drug-Resistant E. coli O78 Infection in Broiler Chicken and Antibody to ND Vaccines

Effect of Probiotic, Prebiotic and/or Fosfomycin in Control of Drug-Sensitive and Drug-Resistant E. coli O78 Infection in Broiler Chicken and Antibody to ND Vaccines

Evaluation of the Efficacy of Three Newcastle Disease Vaccines Produced at the National Veterinary Institute, Bishoftu, Ethiopia, at Different Temperature Storage Conditions

Evaluation of the Efficacy of Three Newcastle Disease Vaccines Produced at the National Veterinary Institute, Bishoftu, Ethiopia, at Different Temperature Storage Conditions

Clarification of a unique mucosal vaccination route for improved systemic and mucosal immune response in broiler

There are often outbreaks of infectious diseases on farms, which not only disrupt production but also cause significant economic losses. Vaccines are given to prevent the spread of these infectious diseases, but they produce only systemic antibodies or antibodies in the mucosa of a particular system. So, a new mucosal vaccination route is needed where the vaccine will produce antibodies in the systemic circulation as well as in the mucosa of many systems. In our study, the cloaca was targeted because it is associated with the mucosa of many systems. Whole-mount and routine histological staining show both lymphatic nodules and diffuse lymphatic tissues in the lamina propria of cloaca. These lymphatic tissues are made up of Bu-1+ B-cells, CD3+ T-cells, and KUL01+ macrophages and monocytes. So, this is a new mucosa-associated lymphoid tissue, named cloaca-associated lymphoid tissue (CALT). The CALT contains antigen-presenting cells (dendritic cells, macrophages, B cells, MHC II molecules, and T cells) and is equipped with blood vessels and high endothelial venules, which indicate its functional status. More antibodies were produced in the treatment group compared to the vehicle control group after administration of the infectious bursal disease (IBD) and the Newcastle disease (ND) vaccine through cloaca. In addition, the cloaca-associated route produces a higher number of antibodies than the other traditional routes, which reveals the uniqueness of this route. Cloacal-vaccinated chickens showed less damage to the follicle and epithelium of the bursa of Fabricius compared to other groups, indicating its lower cytotoxic effect. Therefore, the cloaca-associated mucosal vaccination route produces more antibodies than other mucosal vaccination routes, which will protect the chickens on the farm to a greater extent.

Production of Single Cell Protein (SCP) from the Peel Waste of Pea, Potato, and Banana by Aspergillus Flavus NRRL 21882 as an Efficient Organic Poultry Supplement.

Food protein deficit has become a major issue worldwide, particularly in underdeveloped countries. Scientists are searching for a variety of less expensive solutions to this issue. One of these less expensive methods is to create single cell protein as a substrate from leftover fruit and vegetable waste, which is typically thrown away. In this regard, the fungal strain Aspergillus flavus (NRRL 21882) was used for the synthesis of SCP (single cell protein) from the waste of banana, potato, and pea. In this manner, 30 samples were collected from the whole substrate with a share of 10 samples each from banana, potato, and pea peels, which were in turn dried and powdered finely. The fermentation process was done by the process of solid state fermentation. Aspergillus flavus (NRRL 21882) generated the highest percentage, i.e. 60.67%, of crude protein from the pea peels. The composition of amino acids in crude proteins was also investigated. The findings demonstrated that the highest percentage of aspartic acid (13.34 ± 0.80%) and glutamic acid (14.92 ± 0.69%) was found in A. flavus single cell protein produced from pea peels. Soybean was supplemented with single cell protein in the boilers' diet. Compared to all treated groups, there was a substantial (p ≤ 0.05) increase in the level of antibody titer against the Newcastle disease vaccine. The supplementation of single cell protein with soybean meal had no effect on the levels of liver enzymes. The liver enzymes found in all four groups (A, B, C, and D) were within normal limits. None of the examined groups experienced any change in the feed conversion ratio, with all groups exhibiting an average FCR of 1.6. The current study concludes that broiler health and immunity is increased by supplementing poultry feed with single cell protein.

Advancements in Newcastle Disease Vaccination: Evaluating Traditional and Thermostable Vaccines for Enhanced Control and Efficacy

Newcastle disease (ND) is a critical viral disease in poultry, affecting various avian species worldwide and causing substantial economic losses annually in commercial and backyard poultry operations. Despite its global prevalence, ND can be controlled through proper vaccination and biosecurity management. Over the past 60-65 years, both live attenuated and inactivated ND virus vaccines have been extensively used to mitigate the economic impact of ND. Although live vaccines demonstrate high efficacy against the disease, achieving comprehensive control of ND outbreaks and their financial consequences remains challenging. The primary limitation of most commercially available live vaccines is their heat sensitivity, necessitating a cold chain for quality maintenance, which poses difficulties in village conditions or remote areas of developing tropical countries. This review discusses various methods of ND vaccine administration, their efficacy, and immunogenicity, focusing on the efficacy and stability of thermostable ND vaccines. A thorough understanding of these factors is essential for the long-term control and eradication of ND.

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

Immune Responses in the Harderian Gland After Newcastle Disease Vaccination in Chickens with Maternal Antibodies.

Immune responses in the Harderian gland (HG) were characterized after Newcastle disease virus (NDV) LaSota ocular vaccination in antibody-naïve specific-pathogen-free (SPF) chickens and in chickens of commercial origin with NDV maternally derived antibodies (MDA). Ocular LaSota vaccination of 13-day-old white leghorn SPF chickens elicited serum antibody levels that consistently increased 15 days postvaccination, while the specific IgA response in lacrimal fluids was already detectable 10 days after vaccination. Eleven days postvaccination, the relative abundance of B cells, as well as T-helper cells (CD4+) and cytotoxic T cells (CD8+), in HGs was significantly increased, achieving maximum frequencies 16 days postvaccination. In a second experiment, chickens with MDA originating from NDV-vaccinated commercial white leghorn layer breeders, as well as white leghorn SPF chickens, were vaccinated with NDV LaSota. The LaSota virus successfully replicated in periocular tissues and in the trachea both in commercial and control SPF chickens after vaccination at 2 or 15 days of age (DOA). Vaccination at 2 DOA did not induce a serum NDV antibody response in chickens of commercial origin. In contrast, seroconversion was elicited in commercial chickens upon vaccination at 15 DOA, likely associated with waning of MDA. Unlike systemic IgG responses, vaccination at 2 or 15 DOA elicited strong specific IgA responses in lacrimal fluids in commercial chickens. The IgA response was highest 9 days after vaccination and showed a tendency to decline 15 days postvaccination. Commercial chickens vaccinated at 2 DOA showed increased B cells in HG 10 and 16 days postvaccination. The expansion of B cells in the HG in these chickens is consistent with increased IgA levels detected in lacrimal fluids. In contrast, control SPF chickens showed a more limited B-cell expansion in HG and lower IgA levels. Vaccination at 15 DOA also triggered a greater increase of B cells in HGs in commercial chickens than in control SPF chickens. The B-cell response was accompanied by T-helper (CD4+) cell expansion, occurring both in commercial and control SPF chickens. These cells expanded to a lesser extent when vaccination was performed at 2 DOA compared with vaccination at 15 DOA. CD8+ showed significant expansion irrespective of vaccination day and without differences detected between control SPF chickens and chickens with MDA. We conclude that NDV LaSota elicits vigorous humoral and cell immune responses in the HG. Furthermore, unlike the interference shown by MDA on vaccine-induced serum antibody responses, MDA do not interfere with the mucosal immune response of the HG.

Clinical and Serological Observation of the Newcastle Disease on Commercial Meat Chicken Flocks in Basrah Province, South of Iraq

The current study was conducting to observed Newcastle Disease (ND) in Basrah and evaluated the competence of vaccination schedules used in commercial meat chicken farms. Monitoring of ND was dependent on 20 poultry houses located in Al Zubair, Al Mudaina, Al Qurnah, Garmat Ali Safwan, and Aluhais. The Incidence was recorded based on the clinical history of the disease in the poultry house, clinical signs, and post-mortem findings. ELISA test was estimated to detect Ab titer against ND, including maternal immunity and immune state after vaccination. The results indicated that the Incidence of ND was 80%. ND was not recorded in 20% of poultry houses. Results of the ELISA test showed differences of Ab against ND at different ages of birds, especially at a late stage. Ab titers were very low. The mean of maternal-derived antibodies was 6000 in Belgian, 308 Rose and 2000 for Iranian 501 coop. On the other hand, ND vaccines, available in local markets, showed a good quality (Ma5 + Clone 30) compared with different types, especially ( lasota + IB) Henkar.

Evaluation of the Most Potent of Three Vaccines in Controlling Newcastle Disease in Pullets using different Vaccination Regimen

Newcastle disease continues to pose serious public health and economic challenges to both small holder and commercial poultry worldwide. The aim of this study was to evaluate the most potent vaccine used in the control of Newcastle disease in pullets using different vaccination regimens. Two hundred- and twenty-five-day-old Isa brown pullets were purchased from a reputable hatchery at Ibadan, Nigeria. The chicks were divided into five groups of 45 chicks each. Groups A, B and C were divided into subgroups 1, 2 and 3 consisting of 15 chicks each. Group D was the negative control group which was neither vaccinated nor challenged while group E was the positive control group which was not vaccinated but challenged with Newcastle disease virus (Kudu 113, genotype XVII). The vaccines (La Sota, VG/GA and La Sota clone) were reconstituted as follows: each 1, 000 dose vial of vaccine was reconstituted with 5 ml of water; 0.1 ml of the dissolved vaccine was diluted in 300 ml of clean drinking water and administered to the birds via the oral route. Blood sampling was carried out using standard procedure and ELISA was carried out according to manufacturer’s instruction. There was presence of high maternally derived ND antibodies in the experimental chicks (12,627±1,806 - 17,722±1,607). The La Sota clone vaccine produced more antibodies (3,508±975) which was significantly different (p&lt; 0.05) compared to VG/GA (737±439.77) vaccines. La Sota clone was able to confer 100% protection (p&lt; 0.05) against Newcastle disease with no morbidity and mortality (0%). Vaccination at week 2 was the most effective (p&lt; 0.05) for La Sota and La Sota clone strains but least for VG/GA strain of Newcastle disease vaccines.

Thermostable vacuum foam dried Newcastle disease vaccine: Process optimization and pilot-scale study

Vacuum foam drying (VFD) has been shown to improve the thermostability and long-term shelf life of Newcastle Disease Virus (NDV). This study optimized the VFD process to improve the shelf life of NDV at laboratory-scale and then tested the optimized conditions at pilot-scale. The optimal NDV to T5 formulation ratio was determined to be 1:1 or 3:2. Using the 1:1 virus to formulation ratio, the optimal filling volumes were determined to be 13–17% of the vial capacity. The optimized VFD process conditions were determined to be at a shelf temperature of 25℃ with a minimum overall drying time of 44 h. The vaccine samples prepared using these optimized conditions at laboratory-scale exhibited virus titer losses of ≤ 1.0 log10 with residual moisture content (RMC) below 3%. Furthermore, these samples were transported for 97 days around China at ambient temperature without significant titer loss, thus demonstrating the thermostability of the NDV-VFD vaccine. Pilot-scale testing of the NDV-VFD vaccine at optimized conditions showed promising results for up-scaling the process as the RMC was below 3%. However, the virus titer loss was slightly above 1.0 log10 (approximately 1.1 log10). Therefore, the NDV-VFD process requires further optimization at pilot scale to obtain a titer loss of ≤ 1.0 log10. Results from this study provide important guidance for possible industrialization of NDV-VFD vaccine in the future.Key points• The process optimization and scale-up test of thermostable NDV vaccine prepared through VFD is reported for the first time in this study.• The live attenuated NDV-VFD vaccine maintained thermostability for 97 days during long distance transportation in summer without cold chain conditions.• The optimized NDV-VFD vaccine preparations evaluated at pilot-scale maintained acceptable levels of infectivity after preservation at 37℃ for 90 days, which demonstrated the feasibility of the vaccine for industrialization.

HAEMATOLOGICAL PROFILE OF LAYING HENS AFTER NEWCASTLE DISEASE VACCINATION

Newcastle disease (ND) is a viral disease that can cause high mortality in chickens. Hundreds of chickens died due to ND disease. Morbidity and mortality due to ND disease is very large. Viral diseases cannot be treated with antibiotics. Therefore prevention can only be done by vaccination. However, vaccination failure often occurs, it has been proven that there are still many reports of ND cases. Thus, to find out early before sick chickens are attacked by ND, this research aims to determine the hematological profile including: RBC, Hb, HCT, MCH, MCHC, MCH, PLT, WBC, Eosinophils, Monocytes, Neutrophils and Lymphocytes. The research method was a field survey with purposive sampling with blood sampling as a repeat period. The research sample consisted of 40 laying hens, 30 of which were vaccinated with the active ND vaccine of the Lasota strain and 10 without vaccination. Blood samples were taken with anticoagulation four times, namely once pre-vaccination and three times post-vaccination. The data obtained were analyzed by means of variance followed by the Duncan test using SPSS version 25. The results of the study stated that RBC, Hb, HCT, MCV, Neutrophils and Lymphocytes were significantly different (P&lt;0.05). Meanwhile MCV, MCHC, PLT, WBC, Eosinophils and Monocytes were not significantly different (P&gt;0.05).

Long-Term Protection against Virulent Newcastle Disease Virus (NDV) in Chickens Immunized with a Single Dose of Recombinant Turkey Herpesvirus Expressing NDV F Protein.

Newcastle disease (ND) is a significant infectious disease in poultry, causing substantial economic losses in developing countries. To control ND, chickens must be vaccinated multiple times a year. In order to develop an improved vaccine that provides long-term protection, the F gene from genotype VII NDV was inserted into the herpesvirus of turkey (HVT) vaccine virus using CRISPR/Cas9-mediated NHEJ repair and Cre/LoxP technology. The immunogenicity and protective efficacy of the resulting recombinant vaccines were evaluated through antibody assays and virus challenge experiments. Two recombinant vaccines, rHVT-005/006-F and rHVT-US2-F, were generated, both exhibiting growth rates comparable with those of HVT in vitro and consistently expressing the F protein. One-day-old specific pathogen-free (SPF) chickens immunized with 2000 PFU/bird of either rHVT-005/006-F or rHVT-US2-F developed robust humoral immunity and were completely protected against challenge with the NDV F48E8 strain at 4 weeks post-vaccination (wpv). Furthermore, a single dose of these vaccines provided sustained protection for at least 52 wpv. Our study identifies rHVT-005/006-F and rHVT-US2-F as promising ND vaccine candidates, offering long-term protection with a single administration. Moreover, HVT-005/006 demonstrates promise for accommodating additional foreign genes, facilitating the construction of multiplex vaccines.

Changes in the Transcriptome Profile in Young Chickens after Infection with LaSota Newcastle Disease Virus.

Understanding gene expression changes in chicks after vaccination against Newcastle Disease (ND) can reveal vaccine biomarkers. There are limited data on chicks' early immune response after ND vaccination. Two trials focused on this knowledge gap. In experiment one, 42 13-day-old specific-pathogen-free (SPF) chicks were used. Harderian glands (Hgs) and tracheas (Tcs) from five birds per group were sampled at 12, 24, and 48 h post-vaccination (hpv) to evaluate the gene transcription levels by RNA sequencing (RNA-seq) and RT-qPCR. The results of RNA-seq were compared by glmFTest, while results of RT-qPCR were compared by t-test. With RNA-seq, a significant up-regulation of interferon-related genes along with JAK-STAT signaling pathway regulation was observed in the Hgs at 24 hpv. None of the differentially expressed genes (DEGs) identified by RNA-seq were positive for RT-qPCR. Experiment 2 used 112 SPF and commercial chickens that were 1 day old and 14 days old. Only the commercial birds had maternal antibodies for Newcastle Disease virus (NDV). By RNA-seq, 20 core DEGs associated with innate immunity and viral genome replication inhibition were identified. Genes previously unlinked to NDV response, such as USP41, were identified. This research present genes with potential as immunity biomarkers for vaccines, yet further investigation is needed to correlate the core gene expression with viral shedding post-vaccination.

Effect of different levels of single cell protein and probiotic microorganisms on performance, immunological responses, and intestinal histology in laying hens

AbstractAn experiment was conducted to evaluate the effects of single‐cell protein (SCP), as a valuable by‐product and substitute for soybean meal, and multistrain probiotics on the performance, blood biochemistry, intestinal histomorphology, ileal microbiota, and immune responses in laying hens. Leghorn laying hens were randomly assigned to nine experimental treatments with eight replicates of five birds each. Dietary treatments consisted of three levels of replacement of soybean meal with SCP (0.0%, 30%, and 60%) and three levels of probiotics (0.0, 50, 100 mg/kg) offered through 70 days of main recording. The result indicated that replacing 30% soybean meal with SCP in the diet significantly increased the eggshell weight, thickness, and strength; however, hens receiving 60% SCP replacement showed lower productive performance. During the second 35‐d trial, hens receiving at least 50 mg/kg probiotics produced higher eggshell weight, thickness, and strength than the control hens. Remarkable lower levels of serum cholesterol content were observed in the SCP and probiotic‐supplemented diets. The significant reduction in the ileal pH, Escherichia coli and Clostridium spp. enumerations and a remarkable increase in Lactobacillus count was observed after feeding incremental levels of probiotics. The highest villus height to crypt depth ratio, antibody titer against sheep red blood cells (in secondary response) and Newcastle disease vaccine, as well as egg production and egg mass, were found in the hens that received 30% SCP replacement in combination with 50 or 100 mg/kg probiotic (SCP × Probiotic). The present study concluded that feeding SCP, as a cheap protein alternative source, along with probiotics while reducing production costs can support productive performance via modulating the intestinal microbiomes and health indices and fortifying the immune system in laying hens.

Effects of astragalus extract, levamisole and ascorbic acid on humoral immunity in chickens vaccinated with newcastle disease vaccines

This study was designed to assess the effects of Astragalus extract, levamisole and ascorbic acid on the humoral immune response of chickens vaccinated with live and inactivated Newcastle Disease (ND) vaccines. Sixty day-old Cobb500 broiler chicks were used for the study. At day old, the maternally derived antibodies (MDA) to ND virus was determined and the chicks were then housed in a bio-secured pen with water and feed given ad-lib. On the sixth day, the MDA decay was determined thereafter, the chicks were shared into 4 treatment groups. Group A (Astragalus extract); Group B (levamisole); Group C (ascorbic acid) and Group D (Control) of 15 chicks each. Response to ND vaccinations was determined through bleeding to obtain sera for haemagglutination inhibition test at 7 and 14 days except for the second booster with inactivated Komarov vaccine where it was done at 7, 14 and 21 days post vaccination respectively. Antibody titres in the chicks 7 days post first dose of vaccination with La Sota was high in all the treatment groups above the control with 100 % of the chicks having protective antibody titre of ≥4 log2 until day 30 when the antibody titres in all the groups dropped drastically following the second dose of live La Sota vaccination as the first booster vaccine. However, following the second booster with inactivated Komarov the antibody titres increased in all the treatment groups in comparison to the control especially in groups B and C with GMTs of 5.8 ± 0.19 log2 and 6.1 ± 0.27 log2 respectively. We observed that ascorbic acid and Levamisole may have humoral immuno-stimulating effects on vaccinated chickens through yet to be fully explored mechanism. It is recommended that ascorbic acid or levamisole could be used during vaccinations as immuno-stimulating agents to enhance humoral antibody response in vaccinated flocks.

Evaluation of the Newcastle disease virus genotype VII–mismatched vaccines in SPF chickens: A challenge efficacy study

Newcastle disease virus (NDV) strains, while falling under a single serotype, are classified into distinct genotypes. Genotype VII virulent NDVs pose a significant threat to poultry due to their association with high mortality rates and economic losses. This study aimed to evaluate the efficacy of three commercial live vaccines based on genotype II against genotype VII virulent NDV (vNDV) in specific pathogen-free (SPF) chickens. Forty one-day-old chickens were randomly divided into four groups (n = 10) and inoculated with one dose of each ND pneumotropic vaccine—B1, Clone.12IR, and La Sota—or received phosphate-buffered saline (PBS) as a control at eight days of age via eye drop. At 28 days of age (20th post-vaccination days), chickens were intramuscularly challenged with genotype VII virulent NDV (≥ 105 LD50). Serum samples were collected at 28 days of age (challenge day), 7 and 14 post-challenge days to measure NDV antibodies via the hemagglutination inhibition (HI) test. Cloacal and oropharyngeal swabs were taken on the 3rd, 5th, 7th, and 10th post-challenge days to evaluate virus shedding. Vaccinated groups exhibited significantly higher antibody titers and greater protection levels compared to the control group (P≤ 0.001). While HI antibody titer was not different at 28 and 35 days of age between vaccinated chickens, the Clone.12IR groups showed higher HI antibody titer compared to B1 at day 42 of age (9.43 vs. 7.42; P≤ 0.002). La Sota and Clone.12IR vaccines demonstrated superior protection against mortality compared to the B1 vaccine (90 %, 80% vs. 60 %, respectively) with 6.0 and 2.67 odds ratio of survivability. All three mismatched vaccines effectively curbed the shedding of virulent genotype VII NDV, with 0 % to 11 % positive cloacal samples up to the 3rd post-challenge day. These findings demonstrate that in the experimental setting, the administration of mismatched ND vaccines, particularly La Sota and Clone.12IR, confer protection against genotype VII virulent NDV and control viral shedding, which can help to develop effective vaccination strategies to mitigate the impact of vNDV outbreaks in the poultry farms.