Newcastle Disease Vaccine Research Articles

Effect of different vitamin E sources on growth performance, nutrient utilization, anti-oxidant status and carcass characteristics in broiler chicken

This study aimed to compare the efficacy of supplementation with a synthetic (DL-α-tocopherol acetate) or herbal source of vitamin E on performance of broiler chicken during a 35-days feeding trial. Day-old broiler chicks (180) were randomly assigned to one of four treatment groups, each with three replicates. T1 (control) received a basal diet, Group T2 received a basal diet with synthetic vitamin E @ 100 g/quintal of feed, Group T3 received a basal diet with herbal vitamin E @ 100 g/quintal of feed and Group T4 received a basal diet with synthetic vitamin E @ 50 g/ quintal of feed + herbal vitamin E @ 50 g/quintal of feed. Supplementation of herbal vitamin E enhanced growth performance traits (average weight gain, feed intake, feed conversion ratio and economics of broiler production), retention of nutrients (dry matter, nitrogen, and ether extract), haematological parameters (Hb, PCV, and TEC) and serum total cholesterol in broiler chicks. Antioxidant status revealed significant increase in GSH but not SOD and CAT. A marked increase in the antibody titer against Newcastle Disease vaccine was recorded in the herbal vitamin E supplemented group. The carcass quality was statistically similar among different dietary treatments, however, lowest abdominal fat and meat cholesterol were recorded in the group supplemented with herbal vitamin E. The study depicts that dietary supplementation of synthetic or herbal vitamin E and their combination @ 100 g/quintal of feed improved the growth performance, antioxidant status and carcass quality of broiler chickens; and that herbal vitamin E was economical and more effective as compared to the synthetic vitamin E in improving the performance of broiler chickens.

Lactobacillus plantarum GX17 benefits growth performance and improves functions of intestinal barrier/intestinal flora among yellow-feathered broilers.

Lactobacillus plantarum has recently been found to be a natural source feed additive bacteria with great advantages in food safety and animal welfare. Discovering novel strains with commercial application potentiation could benefit the local poultry industry, and in particular support Chinese farmers. In this study, we tested a recently isolated novel strain of Lactobacillus plantarum GX17 as a feed additive on the growth performance and intestinal barrier functions of 1-day-old Chinese yellow-feather chicks. As good as other commercial probiotics, feeding with Lactobacillus plantarum GX17 showed significant improvements in humoral immune responses and enhanced the immune effect after vaccination for either the Newcastle disease vaccine or the avian influenza vaccine. This study also found that feeding with Lactobacillus plantarum GX17 improved the feed-to-weight ratio and caused a significant increase of the villus length to crypt depth ratio. Furthermore, Lactobacillus plantarum GX17 significantly up-regulated the mRNA expression of CLDN, MUC2, and TLR2, all of which are jejunum-associated barrier genes, indicating an improvement of the intestinal barrier functions by enhancing the tight junction between epithelia cells. These results are comparable to the effects of feeding the commercial complex probiotics that improve the expression levels of CLDN, ocludin, MUC2, TLR2, and TLR4. In terms of maintaining intestinal health, commercial complex probiotics increased the relative abundance of Parabacteroides and Romboutsia, while Lactobacillus plantarum GX17 increased the relative abundance of Pseudoflavonifractor. Our data suggest that Lactobacillus plantarum GX17 could enhance the intestinal absorption of nutrients and therefore improve the growth performance of Chinese yellow-feather chicks. In conclusion, compared with the commercial complex probiotics, Lactobacillus plantarum GX17 has more positive effects on the growth performance and intestinal barrier function of yellow-feather chickens, and can be used as a feed additive.

Poultry health constraints in smallholder village poultry systems in Northern Ghana and Central Tanzania.

Smallholder poultry production is a major contributor to food security and rural livelihoods in low-and middle-income countries. However, infectious diseases limit improvements to smallholder poultry production and performance of the sector in general. Infectious diseases of poultry, especially viral diseases, have major impacts on the health and productivity of flocks and account for significant morbidities and mortalities of birds each year. This study utilized participatory epidemiology approaches to better understand the poultry health constraints and challenges faced by smallholder poultry producers in village poultry systems in Northern Ghana and Central Tanzania. The results show dominance of small-scale semi-intensive and extensive scavenging poultry production systems in the study areas. Newcastle disease ranked as the highest cause of morbidity and mortality in chickens in the two countries. The disease occurred mainly during the months coinciding with the dry season in both countries. Other health challenges among poultry flocks included worm infestation, fowl pox, coryza, and coccidiosis. Producers, especially in rural locations, had poor access to veterinary services and critical inputs necessary for poultry production. In the Northern region of Ghana, producers lacked definitive diagnoses for sick poultry due to a shortage of veterinary personnel and diagnostic laboratories. These challenges point to the need for increased investment in poultry disease control and prevention programs, particularly in rural areas. Interventions focused on expansion of veterinary and agricultural extension services and diagnostic laboratory capacity in rural areas and increased gender-sensitive training to enhance smallholder knowledge in poultry husbandry and disease prevention measures will support the development of the smallholder village poultry systems. Tapping into the diverse genetic reservoir of local chicken ecotypes with enhanced resistance to Newcastle disease through genomic selection, coupled with models for enhancing ND vaccination supply and use in the rural areas are potential future avenues for addressing ND constraints to production.

Immunomodulatory effects of aqueous extracts of Azadirachta indica and Piper Guineense on Newcastle disease vaccination in cockrels

The increased incidence of Newcastle disease (ND) outbreaks in the country even amongst vaccinated flocks, has given rise to the search for other means of boosting the immune system besides vaccination alone. A lot of plants have been shown to possess antimicrobial, antipyretic and anticoccidial effects. This study was designed to evaluate the immunomodulatory effect of the aqueous extracts of the leaves of Piper guineense and Azadirachta indica (Neem) on immune response to Newcastle vaccination in birds. A total of 110 cockrels were used in this study (30 for acute toxicity test and 80 for immuonomodulatory effects of extracts). The 80 cockerels were divided into four groups (A, B, C and D), each consisting 20 birds. Group A and B were treated with 100mg/kg of the aqueous extracts of Azadirachta indica and Piper guineense respectively for the first three weeks. All the birds in groups A to C were vaccinated with Newcastle disease vaccine Lasota (NDV-L) at day 21, while Group D was given distilled water only. Blood samples were taken from all groups on day 1, 7, 14 and 21 post-vaccination. Serum antibody level against ND virus were measured by HI test and antibody titre was found to be significantly (p≤0.05) higher in the group treated with Azadirachta indica but low in those treated with Piper guineense. There was no significant (p≥0.05) difference in the immune response seen in Group A compared to the positive control (Group C), but significantly (p≤0.05) higher compared to the negative control (Group D). It was therefore concluded that the aqueous extract of Azadirachta indica may enhance immunomodulatory effects against Newcastle disease virus, unlike that of Piper guineense.

Pig mange in Ossha Umuahia Southern Nigeiria – A case report

The increased incidence of Newcastle disease (ND) outbreaks in the country even amongst vaccinated flocks, has given rise to the search for other means of boosting the immune system besides vaccination alone. A lot of plants have been shown to possess antimicrobial, antipyretic and anticoccidial effects. This study was designed to evaluate the immunomodulatory effect of the aqueous extracts of the leaves of Piper guineense and Azadirachta indica (Neem) on immune response to Newcastle vaccination in birds. A total of 110 cockrels were used in this study (30 for acute toxicity test and 80 for immuonomodulatory effects of extracts). The 80 cockerels were divided into four groups (A, B, C and D), each consisting 20 birds. Group A and B were treated with 100mg/kg of the aqueous extracts of Azadirachta indica and Piper guineense respectively for the first three weeks. All the birds in groups A to C were vaccinated with Newcastle disease vaccine Lasota (NDV-L) at day 21, while Group D was given distilled water only. Blood samples were taken from all groups on day 1, 7, 14 and 21 post-vaccination. Serum antibody level against ND virus were measured by HI test and antibody titre was found to be significantly (p≤0.05) higher in the group treated with Azadirachta indica but low in those treated with Piper guineense. There was no significant (p≥0.05) difference in the immune response seen in Group A compared to the positive control (Group C), but significantly (p≤0.05) higher compared to the negative control (Group D). It was therefore concluded that the aqueous extract of Azadirachta indica may enhance immunomodulatory effects against Newcastle disease virus, unlike that of Piper guineense.

EVALUTION OF THE BEST VACCINAL ROUTES AGAINST NEWCASTLE IN THE PRODUCTION STAGE OF LAYING HENS

Newcastle disease (ND) is a paramyxovirus-based infectious, highly contagious, and pathogenic avian viral disease. Despite the widespread use of ND vaccinations, ND remains a danger to poultry breeders worldwide. The specific goal of this study was to identify the best vaccination route against ND in the layer hens at production stage following oily vaccine. One hundred chickens at 30 weeks of age were collected from layer flocks (ISSA brown) and randomly divided into four groups. The groups received the following vaccinations: G1: Chicks were vaccinated two doses against ND by (La Sota strain) through drinking water at (30 and 40) weeks. G2: Chicks were vaccinated two doses against ND by (La Sota strain) through cross spray at (30 and 40) weeks. G3: Chicks were vaccinated two doses against ND by (La Sota strain) through intraocular at (30 and 40) weeks. G4: Chicks were not vaccinated and consider as control group. All groups challenge with virulent Newcastle virus isolates in a dose ELD50 105 at 50 weeks. To measure the (IgG, IgA, and IFN-γ) against ND, blood samples were taken at 35, 45, and 55 weeks of age. According to the results of this experiment, the third group, followed by the second group, produced the highest mean (IgG, IgA, and IFN-γ) titres among the vaccinated groups, while the first group produced the lowest titres when compared to the control negative (fourth) group, which recorded the lowest immune response and highly decrease in eggs production. The results were showed that intraocular vaccination with a live vaccine provides layer hens with a higher level of homogenous protection against vvNDV than spraying or drinking water vaccination.

Study of Synergistic Effects of Herbal Meniran (Phyllanthus Niruri L) and Sambiloto (Andrographis Paniculata) as A Substitute Commercial Additive Feed to Improve Immunity Response and Free Chicken Egg Production

This study aims to look at the immune response and egg production of free-range chickens after ND vaccination by administering meniran and Sambiloto extracts. The design used was a completely randomized design. Data on egg production were analyzed using analysis of variance and data on antibody and lymphocyte titers were analyzed descriptively. The results showed that on D+7 after vaccination, there was an increase in ND antibody and lymphocyte titers and in vaccinated chickens the ND titer was in a protective condition (≥log26), whereas in non-vaccinated chickens, the ND titer and lymphocyte levels were in a less protective condition. On H+28 after the vaccine only the vaccine treatment showed a protective condition, but the administration of meniran and Sambilotol extracts was able to maintain the titer rate longer than without giving Meniran and Sambiloto extracts. Drinking water consumption (Sig.941), feed consumption (Sig.890), egg production (Sig.480) and feed conversion (sig.558) showed no difference. Based on the results of the study, the treatment of vaccines and extracts of meniran and Sambiloto gave a better immune response than without being vaccinated. Administration of meniran and Sambiloto extracts was able to maintain the level of immunity compared to no control.

Safety and Immunogenicity of ND Vaccines Used in Nepal

Viral infections, including Newcastle disease (ND), constitute a major health problem in the rapidly growing poultry industry of Nepal. Despite regular vaccination in the commercial farms, ND virus (NDV) outbreaks are frequently reported raising concern over the safety and immunogenicity of live-attenuated vaccines being used. This study was performed to compare the safety and immunogenicity of four commercially available ND vaccines in Nepal after administration at recommended (1X) and higher (10X) dose. There was no safety concern associated with the use of lentogenic live-attenuated ND vaccines even at higher dose. A varying degree of antibody response was observed at recommended and higher doses with the thermostable I-2 vaccine outperforming other groups. A higher dose did not improve antibody response except for the F1 vaccine. To prevent widespread outbreaks in future, regular molecular surveillance to identify the circulating strains of NDV together with the periodic evaluation of immunogenicity and protective efficacy of commercial vaccines is necessary in Nepal.

Evaluation of humoral immunity by IgG measurement in broilers vaccinated with life and killed Newcastle vaccine

Current research objectives evaluated the humeral immunity induced by two different vaccination methods and estimated the efficiency of the commercially available Newcastle disease (ND) vaccine. A total number of 90-day-old unvaccinated chicks were divided equally into 3 groups; each group was vaccinated with different vaccination methods, while group 3 was the unvaccinated control group. Serum was collected from all groups, and five chickens from each group were slaughtered. ELISA measured the levels of IgG; there also were higher in the vaccinated groups (G1, G2) compared with the unvaccinated group. Group 2 also had the best IgG; The higher values of lymphoid organs (Bursa of Fabricius, thymus and spleen) indices were in. While the vaccinated groups were compared to non-vaccinated groups, between vaccinated groups, there was no significant difference (P < 0.05). The best-proven vaccine program in group 2(primary vaccine at 7th day of old by the intraocular vaccine (live vaccine), then boost potion dose at 21st day of old by drinking water vaccine(live vaccine). Keywords: chicks, humeral immunity, vaccine.

A high level estimation of the net economic benefits to small-scale livestock producers arising from animal health product distribution initiatives.

A fundamental challenge for charities that facilitate distribution of animal health products to small-scale livestock producers (SSPs) in low and middle income countries (LMICs) is identifying the products and market mechanisms that provide the greatest positive impact for SSPs and estimating their associated impact. This paper describes a pragmatic approach to modeling the impact of market-led product distribution initiatives based on estimating the net economic benefit of administration of animal health products. The model estimates the economic impact of diseases at the individual animal level for poultry, small ruminants, and cattle. The economic impact of mortality and growth inhibition associated with disease are then estimated in conjunction with the losses averted or recovered by preventing or treating the disease. Economic benefit is estimated in 2014-2017 values and also adjusted to 2023 values. The flexible model structure allows for addition of new geographies, new products, and increased granularity of modeled production systems. Applied to the Global Alliance for Livestock Veterinary Medicines (GALVmed) product distribution initiatives conducted in Africa and South Asia (SA) between 2014 and 2017, the model estimates an adjusted total net economic benefit of 139.9 million USD from sales of vaccines and poultry anthelminthics in these initiatives. Within SSA, the greatest net economic benefit was realized from East Coast fever and Newcastle disease vaccines, while in SA, peste des petits ruminants and Newcastle disease vaccines had the greatest net economic benefits. This translated to an adjusted $37.97 of net economic benefit on average per SSP customer, many of whom were small poultry producers. While the model currently estimates impacts from mortality and growth inhibition in livestock, there is the potential to extend it to cover impacts of further initiatives, including interventions targeted at diseases that impact production of milk, eggs, and reproduction.

Selection of conditions for effective inactivation of Pseudopestis avium virus (Paramyxoviridae: Orthoavulovirus: Avian orthoavulovirus 1) for the production of a Newcastle disease vaccine

Newcastle disease (ND) is classified as especially dangerous pathogen. Its primary source is an infected or recovered bird. The virus shedding begins just in a day after infection, and virus remains in the body for another 2-4 months after the recovery. The complexity of the final elimination of the causative agent of the disease lies in its ability for long-term preservation in the external environment and the possibility of constant circulation in one complex between groups of birds of different sex and age. Therefore, the main element of protecting birds from ND is immunoprophylaxis that is based on vaccines containing an inactivated ND virus (NDV). The aim of the work ‒ is to optimize the parameters of inactivation of the NDV actual strain H with formaldehyde at final concentrations of 0.01, 0.025, 0.05, and 0.1% under temperature conditions of 20 2 and 37 0.5 C. We used a virus-containing suspension of the NDV strain H with an initial biological activity of 10.75 lg EID50/cm3 grown by cultivation in 10-day-old developing chick embryos. On the 16th day after the administration of the tested suspensions of NDV inactivated at different temperatures and concentrations of the inactivant , the geometric mean titers of antibodies to NDV in sera of vaccinated birds were at least 1 : 63 in the hemagglutination inhibition reaction, indicating that the studied inactivated suspensions were antigenically active. The optimal parameters of the inactivation mode (final concentration, temperature and time of inactivation) of the NDV strain H were established. The inactivation process at 37 0.5 C with inactivant concentrations of 0.01, 0.025, 0.05, and 0.1% lasts up to 72, 22, 18, and 12 hours, respectively. The inactivation process at 20 2 C with inactivant concentrations of 0.05 and 0.1% lasts up to 22 and 18 hours, respectively.

Establishment of reverse genetics for genotype VII Newcastle disease virus and altering the cell tropism by inserting TMPRSS2 into the viral genome.

Newcastle disease (ND) is the most important infectious disease in poultry, which is caused by avian orthoavulavirus type 1 (AOAV-1), previously known as Newcastle disease virus (NDV). In this study, an NDV strain SD19 (GenBank accession number OP797800) was isolated, and phylogenetic analysis suggested the virus belongs to the class II genotype VII. After generating wild-type rescued SD19 (rSD19), the attenuating strain (raSD19) was generated by mutating the F protein cleavage site. To explore the potential role of the transmembrane protease, serine S1 member 2 (TMPRSS2), the TMPRSS2 gene was inserted into the region between the P and M genes of raSD19 to generate raSD19-TMPRSS2. Besides, the coding sequence of the enhanced green fluorescent protein (EGFP) gene was inserted in the same region as a control (rSD19-EGFP and raSD19-EGFP). The Western blot, indirect immunofluorescence assay (IFA), and real-time quantitative PCR were employed to determine the replication activity of these constructs. The results reveal that all the rescued viruses can replicate in chicken embryo fibroblast (DF-1) cells; however, the proliferation of raSD19 and raSD19-EGFP needs additional trypsin. We next evaluated the virulence of these constructs, and our results reveal that the SD19, rSD19, and rSD19-EGFP are velogenic; the raSD19 and raSD19-EGFP are lentogenic; and the raSD19-TMPRSS2 are mesogenic. Moreover, due to the enzymatic hydrolysis of serine protease, the raSD19-TMPRSS2 can support itself to proliferate in the DF-1 cells without adding exogenous trypsin. These results may provide a new method for the NDV cell culture and contribute to ND's vaccine development.

Influence of Zinc and Probiotics on Productive Performance, Immune Response and Mineral Content in Muscle of Broiler Chickens

Zinc (Zn) is most commonly added to broiler chickens' feeds. It is an essential nutritional trace element for all forms of life. Probiotics are used to replenish the gastrointestinal flora and assist in maintaining a healthy digestive tract. Two hundred straight-run one-day-old broiler chicks Ross 308 were divided randomly into four equal groups of 50 chicks, each divided into two replicates containing 25 chicks. The control group (T1) was fed a basal diet without any additives, the second group (T2) fed on a basal diet containing 1.5 g/kg Zn, the third group (T3) fed on a basal diet containing 1g/kg probiotic, the fourth group(T4) fed on a basal diet have a combination of Zn 1.5g/kg + probiotic 1g/kg. The result revealed a significant increase (p≤ 0.05) in the mean body weight values, body weight gain, feed intake and feed conversion ratio in the combination group compared to the other groups. Likewise, this group showed significantly increased antibody titers against Newcastle and infections bursal disease vaccines and minerals contained in the pectoral muscle of broilers. In summary, our work recommends that a combination of Zn 1.5g/kg + probiotic 1g/kg could improve productive performance, immunity and chemical composition of minerals.

Engineered Newcastle disease virus expressing the haemagglutinin protein of H9N2 confers protection against challenge infections in chickens

The Newcastle disease (ND) and avian influenza (AI) are two crucial viral ailments of poultry birds. In field conditions, these are controlled by vaccination and biosecurity measures. The cumbersome application process, potential for reversion to the wild pathogen, and financial load on farmers are only a few drawbacks of the currently available ND and AI vaccines. There was a pressing need to develop a stable, safer, bivalent vaccine for these two diseases. Hence, this study adopts the reverse genetic technology, thereby rescuing the recombinant LaSota strain of NDV, which expresses the haemagglutinin (HA) protein of indigenously isolated H9N2 virus (rNDV-H9). The rNDV-H9 was tested in terms of pathogenicity and growth kinetics. Subsequently, the day-old broiler chicks were immunised with rNDV-H9, followed by challenge infection by virulent NDV and H9N2 viruses. The results indicate that immunisation with rNDV-H9 has reduced the shedding of challenge viruses. The clinical progression of the diseases was slowed down, and all the birds were seroconverted. Results in this study indicate that rNDV-H9 is a promising candidate for immunisation in endemic areas of ND and AI, with minimum economic pressure on farmers and reduced vaccinal stress on poultry birds.

Effects of Dietary Supplementation of Vitamin E on Growth Performance and Immune System of Broiler Chickens

As a potent antioxidant, Vitamin E may lessen the potentially harmful consequences of such oxidative stress to protect broilers against immune-pathological damage. Broiler chicken growth and viability are enhanced by Vitamin E supplementation. The present study aimed to investigate the effects of Vitamin E dietary supplementation on broiler chickens’ growth performance and health status. A total of 48 one-day-old Ross chicks were randomly divided into two groups of control and treatment (supplementation of Vitamin E at a dose of 300 mg/kg diet) with three replicates per group. The study included an equal number of Ross breed chicks and Vitamin E dosage in two trials on two different dates (January and March, 2022). In both trials, the obtained results indicated no significant changes in weight gain in the control and treatment groups. In both trials, there were no significant differences in the spleen weight of the control and treated groups; however, from day 1 to 28 of the second trial, the bursa of Fabricius was heavier in the treated group than in the control group. Additionally, Vitamin E had no significant effects on the mitogenic responses to phytohemagglutinin (PHA) and Concanavalin A (Con A). Dosages of 20 and 10 µl for both PHA and Con A did not significantly affect the rate of pure lymphocyte proliferation in chicks fed 300 mg Vitamin E /kg feed. Cell-mediated immunity did not differ significantly between the two trials. The percentages of CD4, CD8, Bu1, and MHCII molecules in the spleen and cecal tonsil of the chicks that received Vitamin E 300 mg/kg feed did not change significantly. The antibody titers against infectious bronchitis and infectious bursal disease vaccines showed no significant differences. On day 42, there was a trend toward an increase in antibody titer in the case of the Newcastle disease vaccine. In conclusion, 300 mg/kg of Vitamin E added to the diet did not improve growth performance and immunity in broiler chicks. Keywords: Broiler chicken, Growth performance, Immune system, Vitamin E

Vaccine Interaction and Protection against Virulent Avian Metapneumovirus (aMPV) Challenge after Combined Administration of Newcastle Disease and aMPV Live Vaccines to Day-Old Turkeys.

Newcastle disease virus (NDV) and avian metapneumovirus (aMPV) are among the most impactful pathogens affecting the turkey industry. Since turkeys are routinely immunized against both diseases, the hatchery administration of the combined respective live vaccines would offer remarkable practical advantages. However, the compatibility of NDV and aMPV vaccines has not yet been experimentally demonstrated in this species. To address this issue, an aMPV subtype B live vaccine was administered to day-old poults either alone or in combination with one of two different ND vaccines. The birds were then challenged with a virulent aMPV subtype B strain, clinical signs were recorded and aMPV and NDV vaccine replication and humoral immune response were assessed. All results supported the absence of any interference hampering protection against aMPV, with no significant differences in terms of clinical scoring. In addition, the mean aMPV vaccine viral titers and antibody titers measured in the dual vaccinated groups were comparable or even higher than in the group vaccinated solely against aMPV. Lastly, based on the NDV viral and antibody titers, the combined aMPV and NDV vaccination does not seem to interfere with protection against NDV, although further studies involving an actual ND challenge will be necessary to fully demonstrate this hypothesis.

Socio-economic and structural barriers in Newcastle disease vaccines uptake by smallholder women farmers in Southeastern Kenya.

The exploitation of the full benefits of chicken rearing by smallholder farmers in Sub-Saharan (SSA) Africa is often impeded by poultry diseases which is compounded by limited uptake of vaccination. We interrogate the structural and socioeconomic factors associated with vaccine uptake by women farmers in Southeastern Kenya. A mixed methods design with a convergent approach for comparison of quantitative and qualitative findings was adopted. This involved the administration of a cross section survey to 1274 households, conduct of 23 Focus Groups Discussions (FGDs) and 7 Key informant Interviews (KIIs). Chi Square and t-tests were used to identify factors associated with vaccine uptake. Logistics regression analysis was used to identify the influence of the structural and socioeconomic barriers to vaccine uptake. Findings indicate that having knowledge of Newcastle disease (ND) vaccine increases the likelihood of farmers vaccinating their chicken by up to 32.5 times (95% CI [8.46-124.53]) with a 1 unit increase in vaccine knowledge. A farmer's distance away from the nearest ND vaccine vendor was found to reduce the likelihood of farmers vaccinating their chicken by up to 4% (95% CI ([0.93-1.00]) for every 1-kilometre increase in distance away from the vaccine vendors. Farmers who considered vaccines to be effective in preventing ND were 39 times (95% CI [6.23-239.8]) more likely to use ND vaccines than those that did not consider ND vaccine to effective. We surmise that a comprehensive approach that addresses increased ND vaccine knowledge among smallholder women chicken farmers, proximity of ND vendors, as well as cost holds the potential for regular and increased ND vaccine uptake.

Gender-Responsive Design of Bacteriophage Products to Enhance Adoption by Chicken Keepers in Kenya.

Women and men keeping chickens in Kenya aspire to have a source of income, feed their families healthy food, and grow their businesses. Managing animal diseases and minimizing input costs enable their success. This study uses qualitative methods to recommend design opportunities for a veterinary product under development in Kenya that contains bacteriophages (phages) that target pathogenic Salmonella strains responsible for fowl typhoid, salmonellosis, and pullorum in chickens and foodborne illness in people. Our findings revealed the interplay between gender and two production systems: free-range and semi-intensive. Chicken keepers in both systems could benefit from phages combined with the orally administered Newcastle disease vaccine, one of the most commonly used preventive veterinary interventions, or phages as a treatment for fowl typhoid. Oral administration is less labor intensive, with greater benefits for women who have less control over family labor and reported doing more care tasks themselves. Men in free-range systems usually pay for veterinary inputs. In semi-intensive production systems, a phage-based product used prophylactically could be an alternative to expensive, intramuscular fowl typhoid vaccines. Keeping layers was common for women in semi-intensive systems, as they are more economically impacted by reduced laying caused by bacterial diseases. Awareness of zoonoses was low, but men and women were concerned about the negative health effects of drug residues in meat and eggs. Therefore, highlighting the lack of a withdrawal period for a phage product may appeal to customers. Antibiotics are used to both treat and prevent diseases, and phage products will need to do both to compete in the Kenyan market. These findings guide the ongoing design of a phage-based product with the goal of introducing a new veterinary product that meets the diverse needs of chicken keepers in Africa and serves as an alternative or complement to antibiotics.

Regional immunity of chicken adipose tissue responds to secondary immunity induced by Newcastle disease vaccine via promoting immune activation and weakening lipid metabolism

Adipose tissue (AT) is considered as a regional immune organ and plays an important role in the anti-infection immune response. However, the function and mechanism of chicken AT in response to secondary immune response remain poorly understood. Here, we used mRNA and microRNA (miRNA) sequencing technology to survey the transcriptomic landscape of chicken abdominal adipose tissue (AAT) during the first and second immunization with Newcastle disease virus (NDV) vaccine, and carried out bioinformatics analysis, such as Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis, protein-protein interaction (PPI) analysis, and miRNA-mRNA integrated analysis. The results indicated that chicken AAT actively responded to the secondary immune response. DNA replication and cytoskeleton regulation as the regulatory functions of immune activation changed significantly, and weakened lipid metabolism was an effective strategy for the secondary immunity. Mechanically, the regulatory network between the differentially expressed miRNAs (DEMs) and their targeted differentially expressed genes (DEGs), such as miR-206/miR-499-5p-nuclear receptor subfamily 4 group A member 3 (NR4A3)/methylsterol monooxygenase 1 (MSMO1) pathway, was one of the potential key mechanisms by which AAT responded to the secondary immune response. In conclusion, regional immunity of chicken AT responds to secondary immunity by promoting immune activation and weakening lipid metabolism, and this study can instruct future research on antiviral strategy.

Fowl Adenovirus Infection – Potential Cause of a Suppressed Humoral Immune Response of Broilers to Newcastle Disease Vaccination

Abstract Fowl adenovirus infections have a significant economic impact, especially in the production of broilers. It is considered the leading cause of three syndromes: adenoviral gizzard erosions and ulcerations, inclusion body hepatitis, and hepatitis-hydropericardium syndrome. A critical feature of this virus is its immunosuppressive effect, via suppressing humoral and cellular immunity. In this study, we examined the humoral immune response after administration of the Newcastle disease vaccine in broiler flocks with previously confirmed seroconversion against Fowl adenovirus. The study was conducted on 5 farms. A total of 220 chickens, five weeks of age, showing no clinical signs of the disease, were included in this study. The control group consisted of 20 chickens from a negative farm. Chickens were vaccinated with commercially available live NDV vaccines between 11 and 13 days of life. ELISA determined the presence of specific antibodies against FAdV in a total of 130/200 (65%) blood sera. Depending on the farm, seroprevalence ranged from 30-100%. The presence of specific antibodies against NDV was determined three weeks after vaccination using the hemagglutination inhibition assay. A positive hemagglutination inhibition (HI) titer (≥ 16) was found in 41/200 (20.5%) sera, which was significantly less compared to the control farm, where a positive HI titer was found in 20/20 (100%) sera. The results of our study indicate the immunosuppressive effect of FAdV in subclinically infected birds and highlight the need for its diagnosis, prevention, and control.