Newcastle Disease Virus Antibodies Research Articles

Immunostimulatory and Antibacterial Effects of Cannabis sativa L. Leaves on Broilers.

The aim of this study was to evaluate the effect of dried Cannabis sativa L. leaves as a phytogenic mixture added to broiler feed on CD4+ and CD8+ T lymphocyte subpopulations, Newcastle disease virus (NDV) antibody titres, and the presence of E. coli in faecal samples. The study was conducted on 100 male Ross 308 broilers, divided into four groups of 25 broilers, for a 42-day research period. The groups were housed separately in boxes on a litter of softwood shavings and were fed starter mixture from day 1 to day 21 and finisher mixture from day 22 to day 42. Industrial hemp (C. sativa) was grown in the Crkvina area, Croatia (latitude: 45°18'46.8″ N; longitude: 15°31'30″ E). The hemp leaves were manually separated, sun-dried, and ground to a powder. The mixture offered to the control group did not contain cannabis leaves, whereas the three experimental groups received mixtures containing mixed cannabis leaves in a quantity of 10 g/kg, 20 g/kg, or 30 g/kg (E_10, E_20, and E_30, respectively). The mean NDV antibody level was uniform in all study groups until post-vaccination day 14 and increased comparably with time. The percentage of CD4+ and CD8+ lymphocytes in the peripheral blood subpopulation showed statistically significant differences (p < 0.001) in the E_20 group as compared with the control group and both the E_10 and E_30 groups throughout the study period. As the broiler age increased, the CD4+-to-CD8+ ratios also increased and were statistically significant (p < 0.0001) on day 42 in all experimental groups as compared to the control group. Comparing the control group with the experimental groups indicated that the bacterial count was lower in broiler groups having received feed with the addition of 20 g/kg and 30 g/kg C. sativa leaves. In conclusion, the C. sativa leaves were found to elicit a favourable immunomodulatory effect on cell-mediated and humoral immune responses in broilers via increased CD4+ and CD8+ lymphocyte subpopulations and higher CD4+:CD8+ cell ratios, thus indicating enhanced immune function capacity. In addition, C. sativa leaves may have complementary effects on the broiler post-vaccination immune response, increase broilers' resistance to infectious diseases, reduce the effect of stress associated with vaccination, and improve broiler health and welfare.

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.

Effects of Natural Guard Liquid (an Essential Oil-Based Product) on Growth Performance, Hematological Profile, and Antibody Response to Newcastle Disease Virus in Broiler Chickens

Natural guard liquid (NGL) is an immunomodulator consisting of an essential oil blend (lavender oil, eucalyptus oil, and pine oil) that can improve the immunity (IgG) of animals. The objective of this research was to assess the effectiveness of a mixture of NGL comprising of essential oil (eucalyptus, lavender, and pine oil) on growth performance, hematological profile, and antibody titer response to the Newcastle disease virus (NDV) in Lohman strain broiler chickens. A total of 400-day-old unsexed broiler chickens with an average weight of 42.48 ± 2.08 g were randomly distributed into four groups, each comprising two replications with 50 chicks. The control group, T0, received no essential oil, while other treatment groups, T1, T2, and T3, were administered NGL at 80, 100, and 200 ppm, respectively. The mixture was administered in drinking water for 30 days. The animals had received vaccinations at the Hatchery, including active NDV, inactive NDV, and Gumboro. Regular recordings were made for feed consumption, water intake, mortality, and body weight. Blood samples for routine hematological examination (hemoglobin, erythrocytes, packed cell volume, erythrocyte index, leucocytes, and differential leucocytes) and immune parameter (NDV antibody titer) assessment were collected at the onset as well as after 15 and 30 days of treatment. The hemoglobin levels, erythrocytes, total leukocytes, lymphocytes, and Heterophil-lymphocyte index showed significant differences in groups T1 and T2 compared to T0. While the NDV antibody titer showed a significant difference at T2 compared to T0, it was not significantly different at T1 and T3. The best results and performance was indicated in T2 (100 ppm), characterized by body weight (1,839 g), and feed conversion ratio (1.573). The hematological profile in the T2 group included hemoglobin (11.78 g/dL), total erythrocytes (2.82 ×106 u/L), total leukocytes (52.67 ×103 u/L]), and the NDV antibody titer (48 ± 10.20) in the fifth week. In conclusion, the optimum dose of NGL is 100 ppm, which significantly influences growth performance, hematological profile, and antibody titer against NDV. Keywords: Antibody titer, Broiler chicken, Growth performance, Hematological profile, Natural Guard Liquid

Limosilactobacillus reuteri peptidoglycan alleviates aflatoxin B1-induced toxicity through adsorbing toxins and improving growth, antioxidant status, immunity and liver pathological changes in chicks

ABSTRACT 1. The objective of this study was to investigate the protective effects of a peptidoglycan produced by Limosilactobacillus reuteri against aflatoxin B1 (AFB1) induced toxicity in vitro and in vivo in broiler chicks. 2. Toxin adsorption experiments were carried out firstly in vitro. These experiments indicated that the absorption efficiency of the peptidoglycan for AFB1 was 64.3–75.9%. 3. In the in vivo experiments, Hy-Line Brown chicks were fed a diet containing AFB1 at 71.43 µg/kg with and without peptidoglycan supplementation at concentrations of 100, 200, or 300 g/kg feed from 0–42 d of age. 4. The peptidoglycan supplementation in AFB1-contaminated diets resulted in significant improvements in terms of average daily gain, feed intake, feed conversion ratio, white blood cell count, haemoglobin content, glutathione peroxidase activity, immunoglobulin (Ig) A, IgG, IgM and Newcastle disease virus antibody titres (p < 0.05) and diminished liver steatosis. 5. In conclusion, peptidoglycan supplementation alleviated AFB1-induced toxicity through adsorbing toxins and improving growth performance, antioxidant ability, immunity and liver pathological changes in chicks. The optimal supplemental dose was 200 mg/kg in feed.

Florfenicol can inhibit chick growth and lead to immunosuppression1

Florfenicol (FLO) is a chemically synthesized broad-spectrum antimicrobial agent of amide alcohols for animals, which is one of the most widely used antimicrobials in livestock, poultry, and aquaculture. With the use of FLO, more and more attention has been paid to its hematopoietic toxicity, immunotoxicity, genotoxicity, and embryotoxicity. In this study, SPF chicks at the age of 3 d began to drink water with the FLO at a dose of 100 mg L-1 for six consecutive days, and the growth performance of chicks was monitored, the effect of FLO on immune organs was detected by pathological examination and TUNEL apoptosis staining. In order to evaluate the level of organism immunity, the level of Newcastle disease virus antibody in serum was detected by hemagglutination inhibition test, the content of cytokines (IL-1, IL-2, IL-6, TNF-α, IFN-γ) in serum was detected by ELISA, and the transcription of interferon-related genes (IRF-7, 2’-5’OAS, Mx1) and cytokine genes (IL-6, TNF-α, IFN-γ) in immune organs were detected by real time fluorescence quantitative PCR. The results showed that the early application of FLO could inhibit the growth and development of chicks, and the body weight and immune organ index of the treatment group were lower than those of the control group. Histopathological examination showed that there was a decrease in the number of lymphocytes in the bursa of Fabricius in the treatment group in the early stage of drug withdrawal, and the results of TUNEL apoptosis staining in the bursa of Fabricius showed that obvious lymphocyte apoptosis occurred in the FLO treatment group. Compared with the control group, the transcription levels of interferon-related genes IRF-7, 2’-5’OAS, and cytokine genes IL-6, TNF-α and IFN-γ in FLO treatment group decreased to a certain extent, while the transcription level of Mx1 gene had no significant difference at all time points. The level of serum NDV antibody and the contents of cytokines IL-1, IL-2 and IFN-γ in the FLO treatment group were significantly lower than those in the control group in the early stage of drug withdrawal, but recovered gradually in the later stage. This study showed that FLO has a certain degree of effect on the immune function of chicks, and the results of the study laid the foundation for further research on the mechanism of FLO-induced immunotoxicity.

Immunomodulatory effect of Atractylodis macrocephala Koidz. polysaccharides in vitro

Vaccination is still the main method of preventing most infectious diseases, but there are inefficiencies and inaccuracies in immunization. Studies have reported that Atractylodis macrocephalae Koidz. polysaccharides (RAMP) have immunomodulatory effects, but the mechanisms involved in whether they can modulate the immune response in chickens are not yet clear. The aim of this study was to investigate the effect of RAMP on lymphocytes functions by analyzing cell proliferation, cell cycle, mRNA expression of cytokines and CD4 +/CD8+ratio. To identify potential molecules involved in immune regulation, we performed a comprehensive transcriptome profiling of chicken lymphocytes. In addition, the adjuvant effect of RAMP was evaluated by detecting indicators of hemagglutination inhibition. When lymphocytes were cultured with RAMP in vitro, the proliferation rate of lymphocytes was increased (P < 0.01), more cells in S phase and G2/M phase (P < 0.01) and the mRNA expression of IFN-γ was upregulated (P < 0.05), while the mRNA expression of TGF-β (P < 0.01) and IL-4 (P < 0.05) was downregulated and the CD4 +/CD8+ratio was increased (P < 0.05). Transcriptomic results showed that RAMP increased the expression of HIST1H46 (P < 0.05) and CENPP (P < 0.05). Validation of qPCR showed that RAMP may play an important role in regulating cellular immunity by downregulating the Notch pathway. The results also showed that RAMP could increase the serum Newcastle disease virus antibody levels in chickens. These data suggest that RAMP could enhance immune function of lymphocytes and was a candidate vaccine adjuvant in chickens.

Serological evidence of Newcastle disease virus antibodies in wild birds in Zaria, Kaduna State, Nigeria.

Wild birds have been reported to be reservoirs of viral diseases of poultry, and play an epidemiological role in their maintenance and spread. A serological survey was undertaken to determine the evidence of Newcastle disease virus (NDV) antibodies in wild birds in Zaria Kaduna State, Nigeria. A total of 150 apparently healthy wild birds comprising 30 each laughing dove, speckled pigeons, cattle egrets, village weavers and African silver bills were sampled. Sera collected were analysed for the presence of antibodies against NDV and avian paramyxovirus‑2 (APMV‑2) using the haemagglutination inhibition test. The results showed an overall seroprevalence of 4% (95% CI: 2.05‑10.1) to NDV. African silver bill showed a seroprevalence of 10.0% (95% CI: 2.61‑24.9) NDV antibodies while seroprevalence of 3.3% (95% CI: 0.16‑15.4) was recorded for cattle egrets, village weavers and laughing doves respectively. No statistically significant difference existed for NDV seroprevalence (P>0.05) among the different species of wild birds. All the 150 sera tested negative for APMV‑2 antibodies. The result of this study confirmed the exposure of wild birds to NDV in the study area. Continuous surveillance with isolation and characterization of NDV in the wild birds is therefore recommended for strategic planning for control.

Supplementation of ginger root extract into broiler chicken diet: effects on growth performance and immunocompetence

Ginger contains bioactive compounds that possess anti-inflammatory and antimicrobial properties. In this study, 432-day-old Ross 708 broiler male chicks were randomly allocated to 6 dietary treatments to investigate the effect of ginger root extract (GRE) on immunocompetence and growth performance to 6 wk of age. Treatment 1 (CON) consisted of chicks fed a corn-soybean meal (SBM), a base diet without GRE. Treatment 2 (MX) chicks were given basal diets containing bacitracin methylene disalicylate (BMD) at 0.055 g/kg. Treatments 3 (GRE-0.375%), 4 (GRE-0.75%), 5 (GRE-1.5%), and 6 (GRE-3%) were fed similar diet to control with GRE supplemented at 0.375%, 0.75%, 1.5%, and 3%, respectively. Moreover, HPLC analysis of GRE was carried out to determine the concentration of bioactive compounds found in GRE. Each treatment consisted of 6 replicate pens with 12 chicks/pen. Bodyweight (BW) and feed conversion ratio (FCR) were recorded. Results show that the concentration of bioactive compounds increased with increasing GRE supplementation. Likewise, dietary GRE supplementation did not have any detrimental effect on growth performance parameters up to 1.5%, as values for BWG was not different from CON and MX; however, 3% GRE had the poorest FCR and a lower BWG as compared to other treatments. On d 27 and d 41, fecal and cecal concentrations of total bacteria count (TBC), Escherichia coli, Lactobacillus spp., and Bifidobacterium spp enumerated using selective plating media showed that GRE supplementation significantly reduced (P < 0.05) the amount of TBC and E. coli but increased the number of beneficial microorganisms such as Lactobacillus spp. and Bifidobacterium spp. On d 20, no significant differences were observed (P > 0.05) among all treatments for antibody titer against Newcastle disease virus and total IgY antibodies; however, on d 27, GRE-0.75% had the highest value for both immune indicators and was not different from MX. Dietary supplementation of GRE up to 1.5% enhanced the immune system and suppressed E. coli while promoting the growth of healthy bacteria, without any detrimental effect on growth performance.

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.

Protection against Newcastle disease in chicken after vaccination in Dong Nai province

The aims of the study were to evaluate the efficiency of protection after vaccination and to find out the circulation of Newcastle disease virus (NDV) in chicken. The overall purpose was to establish the Newcastle disease’s safety areas for chicken production in Dong Nai province. At two sampling times in 2020, we collected total 1,260 blood samples at 21 days after vaccination, which were from 125 chicken smallholdings at the first sampling, and from 42 smallholdings for the second one. The swab samples included 420 pooled samples in 7 districts of the province. The serum samples were examined NDV antibody after vaccination by using HA and HI, and the swab samples were used to determine circulation of NDV based on PCR test. The results showed the average of protective rate was 54.7%, and was seen differently between two sampling times (60.2% and 49.2%, respectively) (P < 0.05). The protective rate was highest 90.0% in Cam My district, and lowest in Dinh Quan (37.8%) at the first sampling time. However, at the second time, the protective rate was highest in Long Khanh City (81.1%), while Long Thanh district was lowest (18.9%). The protective rates were obviously different among 7 districts of the province, husbandry areas (district groups named 1, 2, 3, 4), and farm sizes (<200, 200-1,000, >1,000 chicken) at the first sampling time (P < 0.01); however, at the second time the rates displayed the same among levels of factors (P > 0.05). The PCR results indicated no presence of NDV in all swab samples. That was one of the good bases to set up the Newcastle disease’s safety areas for chicken production in Dong Nai province.

Effect of dietary supplemental vitamin C and betaine on the growth performance, humoral immunity, immune organ index, and antioxidant status of broilers under heat stress.

Heat stress (HS) has become one of the important factors affecting the development of animal husbandry. The purpose of this experiment was to investigate whether vitamin C (Vc) and betaine (Bet) improve immune organ index and humoral immunity by enhancing the antioxidant status of immune organs, thus protecting broilers from HS-induced injuries. A total of 200 28-day-old Ross 308 broilers were randomly assigned into 5 groups (n = 4 replicates/group, 10 broilers/replicate) which were reared at different ambient temperatures (24 ± 1°C or 33 ± 1°C). The control group fed basal diet, while high-temperature groups were either fed a basal diet (HS group) or a basal diet supplemented with 250-mg Vc/kg diet (HSVc group), 1000-mg Bet/kg diet (HSBet group), and 250-mg Vc plus 1000 mg Bet/kg diet (HSVcBet group), respectively. On day 42, growth performance, humoral immune function, immune organ index, and antioxidant capacity were measured. HS reduced the productive performance of broilers, antibody potency against the Newcastle disease virus (NDV) and sheep red blood cells (SRBC), indices of thymus and bursa, and antioxidant capacity of immune organs. Adding Vc alone or in combination with Bet improved performance, NDV and SRBC antibody potency, thymus and bursa indices, and antioxidant capacity of immune organs in heat-stressed broilers, with the most effective being combination. In summary, HS reduces the antioxidant capacity and immune organ development status of broiler immune organs. Vc and/or Bet can improve the development of immune organs and restore part of the production performance by regulating the antioxidant status of immune organs, among which the combined addition of Vc and Bet has the best effect.

Development and Evaluation of a Blocking Lateral Flow Assay Strip for Detection of Newcastle Disease Virus Antibodies.

Newcastle disease (ND) is an acute septicemic infectious disease caused by Newcastle disease virus (NDV). Considering that vaccination is currently the main modality for the prevention of ND, it is essential to assess the effectiveness of clinical immunization. In this study, we have developed a blocking lateral flow assay (bLFA) strip for the rapid detection of NDV antibodies using the monoclonal antibody 9C1 against haemagglutinin-neuraminidase (HN), which allows for the determination of an NDV-specific antibody titer within 10 min at room temperature. In addition, the bLFA strip has no cross-reactivity with the positive serum of other avian pathogens including avian influenza subtypes H5, H7, and H9, MD, IBD, IB, EDS, and avian adenovirus. The ability of the bLFA strip for detecting a neutralizing antibody was also estimated. The results showed that the chicken NDV hyperimmunized serum had a complete blocking (100%) titer of 11 log 2, and half-blocking titer of 13 log 2, which are 4 times less than and the same as that of the HI test (13 log 2), and 8 and 2 times less than that of the VN test (14 log 2), respectively. A total of 510 clinical samples were tested for NDV antibodies. The coincidence rate between the results of the bLFA strip and HI test was 97.65%. Therefore, it is an ideal alternative method for assessing the clinical immunity of ND vaccines in the field in real-time.

Seroprevalence of Newcastle disease in indigenous chickens in Ilorin, Kwara State, Nigeria

Newcastle disease (ND) is a disease of high economic importance to poultry farmers in Nigeria. Its impact on poultry include illness of poultry, reduction in egg production, immunosuppression, and death. This study was carried out to determine the prevalence of Newcastle disease in indigenous (local) chickens from 2 poultry abattoirs in the Ilorin metropolis. A total of 400 blood samples were aseptically collected in plain bottles from the jugular veins of local chickens at slaughter using exsanguination and transported to the laboratory in batches. Sera samples were harvested from the blood by centrifugation at 3000 rpm for 10 minutes, after which they were stored at -20oC before serological assay. The sera were subjected to Haemagglutination Inhibition (HI) test to check for the presence of Newcastle disease virus (NDV) antibody following a standard procedure with titer values for each sample recorded. The geometric mean of the HI antibody titer (GMT) and the percentages of detectable NDV HI antibody titer were calculated using descriptive statistics. Of the 400 serum samples examined, 53 (13.25%) were positive for ND antibodies, with titre value ≥ 1:16. The location from which the birds were selected had no significant relationship with the prevalence of ND antibodies as both Oja tuntun (11.9%), and Ipata market (14.6%) had a closely similar prevalence of antibodies (p &gt; 0.05). The feather arrangement of birds did not also have any significant impact on the prevalence of antibodies (p &gt; 0.05). However, in this study, we observed a higher prevalence of antibodies among hens (14.7%) than in cocks (12.5%) or growers (8.9%). The high prevalence of ND antibodies in indigenous chickens in the study area showed the endemicity of the disease in the study areas. With most of the chickens are not vaccinated amid non-compliance to vaccine administration for local chickens. There is a need for poultry farmers in the study location to be educated on the importance of vaccinating poultry birds against ND.

Effects of aflatoxin B1 on growth performance, antioxidant status, immune response, and pro-inflammatory cytokine mRNA expression in ISA chicks.

The research evaluated the effects of Aflatoxin B1 on growth performance, antioxidant status, immune response, and pro-inflammatory cytokine mRNA expression in ISA chicks. In total, 240 7-day-old ISA chicks were randomly assigned to four treatment groups. The control group comprised chicks fed a basal diet. The aflatoxin (AFB1)-treatment groups (T1, T2, and T3) comprised chicks fed the basal diet supplemented with AFB1 at concentrations of 5, 8, and 10 μg/kg, respectively. The growth performance, antioxidant status, immune responses, and pro-inflammatory cytokine mRNA expression in all groups were measured. In the T1 treatment group (receiving the lowest AFB1 dose), a reduction in the Newcastle disease virus antibody (NDV-Ab) titer, and increases in interleukin 2 (IL-2), IL-6, and interferon γ (IFN-γ) mRNA levels were observed on days 21 and 42 (P < 0.05). Treatment with the higher AFB1 doses (groups T2 and T3) reduced the chicks' growth performance on days 21 and 42, measured as reductions in body weight (BW) and average daily gain (ADG) compared with the control group. In the T2 and T3 groups, the total antioxidant capacity (T-AOC), glutathione peroxidase (GPX) and superoxide dismutase (SOD) activities, serum immunoglobulin A (IgA) and IgG levels, and IL-2, IL-6, and IFN-γ levels were also lower than in the control group. On days 21 and 42, these two groups also showed increased malondialdehyde (MDA) content, higher feed to gain ratio (F/G), and higher IL-2, IL-6, and IFN-γ mRNA levels than the control group (P < 0.05). The T2 and T3 groups also showed reduced T-AOC, NDV-Ab titer, IL-2 content, and GPx-1 mRNA levels on days 21 and 42 (P < 0.05), increased IL-6 and IFN-γ mRNA levels on day 21, and increased F/G and MDA content on day 42 (P < 0.05) compared with group (T1). Increased MDA content and IL-6 mRNA levels in the liver and ileum were observed in group T3 compared with group T2 on day 21, and lower IgM and IL-6 levels were observed on days 21 and 42 (P < 0.05). In conclusion, our data showed that AFB1 exposure resulted in dose-dependent oxidative and inflammatory damage, immunosuppression, and a decline in the growth performance of chicks.

Detection of Newcastle Disease antibodies amongst local chicken slaughtered in live bird markets in Kaduna, Nigeria

Newcastle Disease Virus (NDV) constitutes a major constraint to the poultry production system in Nigeria. This study was carried out to investigate the seroprevalence of NDV antibodies in local chickens (Gallus domesticus) slaughtered in five different live bird markets (LBMs) in Kaduna metropolis, Nigeria. Three hundred blood samples were collected and screened for antibodies against NDV using Haemagglutination Inhibition (HI). An overall seroprevalence rate of 23% (95%:CI18.5-28.0) was recorded in this study. Seroprevalence based on different LBMs revealed a higher prevalence of 28.3% (95% : Cl 18.0-40.7) in Sabo market, followed by Sokoto road market 26.7% (Cl:16.7-38.9), Kawo market 18.3% (95% Cl: 10.0-29.6), Railway market 13.3% (Cl:6.4-23.5), and the lowest prevalence was recorded in central market 11.7% (Cl:5.2-21.7). The difference in seroprevalence among the LBMs was not statistically significant (p &gt; 0.05). Higher seroprevalence of NDV antibodies in female birds 30.5 % (Cl: 24.1-37.6) was recorded compared to male 13.9% (Cl: 8.3-21.4). The study indicated that NDV is endemic in the population. LBMs location had no significant influence on the seroprevalence of NDV in the study area. The difference in seroprevalence between sexes was statistically significant (p &lt; 0.05). Therefore, this study demonstrated the need for a regular strategic vaccination programme against NDV in local chickens in Kaduna metropolis.

Seroprevalence of Newcastle disease virus antibodies in village chickens in the three senatorial zones of Plateau State, Nigeria

The most common cause of death in village chickens is Newcastle disease (ND). A study was conducted to evaluate the seroprevalence of ND in the three senatorial zones of Plateau State using the haemagglutination inhibition (HI) test. Blood samples were collected from 389 village chickens of various ages and sexes that were maintained on extensive system of management in nine Local Government Areas (LGAs) across the three Senatorial zones. The overall seroprevalence of ND virus antibodies in village chickens was found to be 36.8% which differed statistically (p &gt; 0.05) between LGAs, with the highest prevalence of 8.7% (CI: 6.3–11.9) and lowest prevalence of 1.5% (CI: 0.7–3.3) in Bokkos and Qua’an Pan LGAs, respectively. Also, seroprevalence of NDV antibodies differed significantly (p &gt; 0.05) between the three senatorial zones, with 17.5% (CI: 14.0-21.6) in the Northern senatorial zone and 6.7% (CI: 4.6-9.6) in Southern senatorial zone. In the three senatorial zones of Plateau State, this study found prevalence of ND virus antibodies in village chickens. There is a need to increase awareness regarding the importance of vaccinating village chickens to protect them.

A study of risk factors associated with Newcastle disease and molecular characterization of genotype XIII Newcastle disease virus in backyard and commercial poultry in Assam, India

The continuous emergence of Newcastle disease virus (NDV) poses a persistent threat to the poultry industry. Recent increasing outbreaks of NDV in the North East region of India have highlighted the need to closely monitor and analyze the potential risk factors for Newcastle disease (ND) outbreaks. In the present study, an attempt was made to genotype the circulating Newcastle disease virus (NDV) in the backyard and commercial poultry flocks in Assam, India. Sera samples from unvaccinated backyard poultry flocks and tissue samples of ND suspected cases were collected and tested for the presence of NDV antibodies using the Haemagglutination inhibition (HI) test. A total of seven NDV isolates were analyzed from different districts of Assam, India, both genotypically and pathotypically. All isolates were characterized as virulent, carrying 112RRKQRF117 amino acid residues at the cleavage site. As determined by phylogenetic analysis, the isolates clustered with members of genotype XIII of class II NDV. Further analysis of risk factors of ND occurrence was conducted through a questionnaire survey. All the results indicated an occurrence of genotype XIII of NDV in the farms with inadequate biosecurity and farming practices.

Expression of NDV HN protein in rice and development of a semi-quantitative rapid method for detection of antibodies

The aim of this study was to develop a semi-quantitative immunochromatographic method for rapid detection of Newcastle disease virus (NDV) antibodies by expressing HN protein in rice endosperm bioreactor. The recombinant plasmid pUC57-HN was digested by MlyⅠ and XhoⅠ to retrieve the HN gene, while the intermediate vector pMP3 containing promoter, signal peptide and terminator was digested by NaeⅠ and XhoⅠ. The HN gene and the linearized pMP3 were purified and ligated to form a recombinant plasmid pMP3-HN1. Subsequently, pMP3-HN1 and plant vector pCAMBIA1300 were digested by EcoRⅠ and Hind Ⅲ, and the HN1 gene was cloned into pCAMBIA1300. The recombinant plasmid pCAMBIA1300-HN1 was introduced into Agrobacterium tumefaciens EHA105 by electrotransformation, and the pCAMBIA1300-HN1 was transferred into rice callus by agrobacterium-mediated method. After dark culture, callus screening, differentiation, rooting and transplanting, transgenic rice seeds were obtained 4 months later. PCR identified that the HN gene has been inserted into the rice genome. SDS-PAGE and Western blotting indicated that the HN protein was successfully expressed in the positive rice endosperm. The purity of the HN protein was more than 90% by SP cation exchange chromatography and gel filtration chromatography. According to the national standards for the diagnostic techniques of Newcastle disease HI test (HI≥4log2, positive antibody reaction), a colloidal gold labeled purified HN protein was used to prepare a semi-quantitative test strip by double-antibody sandwich method for rapid detection of NDV antibody. The results showed that the test strip did not cross-react with positive sera against other viruses, and the sensitivity of the test strip reached 1:102 400 for standard positive sera of Newcastle disease. Testing of a total of 308 clinical sera showed that the compliance rate of the test strip with HI test was 97.08%, and the Kappa value was 0.942. In conclusion, high purity recombinant HN protein was obtained from rice endosperm, and a simple, rapid, highly sensitive and highly specific semi-quantitative immunochromatographic strip was developed. The test strip could be used for immune evaluation of the Newcastle disease vaccine.

Intranasal Immunization with a Recombinant Avian Paramyxovirus Serotypes 2 Vector-Based Vaccine Induces Protection against H9N2 Avian Influenza in Chicken.

Commercial inactivated vaccines against H9N2 avian influenza (AI) have been developed in China since 1990s and show excellent immunogenicity with strong HI antibodies. However, currently approved vaccines cannot meet the clinical demand for a live-vectored vaccine. Newcastle disease virus (NDV) vectored vaccines have shown effective protection in chickens against H9N2 virus. However, preexisting NDV antibodies may affect protective efficacy of the vaccine in the field. Here, we explored avian paramyxovirus serotype 2 (APMV-2) as a vector for developing an H9N2 vaccine via intranasal delivery. APMV-2 belongs to the same genus as NDV, distantly related to NDV in the phylogenetic tree, based on the sequences of Fusion (F) and hemagglutinin-neuraminidase (HN) gene, and has low cross-reactivity with anti-NDV antisera. We incorporated hemagglutinin (HA) of H9N2 into the junction of P and M gene in the APMV-2 genome by being flanked with the gene start, gene end, and UTR of each gene of APMV-2-T4 to generate seven recombinant APMV-2 viruses rAPMV-2/HAs, rAPMV-2-NPUTR-HA, rAPMV-2-PUTR-HA, rAPMV-2-FUTR-HA, rAPMV-2-HNUTR-HA, rAPMV-2-LUTR-HA, and rAPMV-2-MUTR-HA, expressing HA. The rAPMV-2/HAs displayed similar pathogenicity compared with the parental APMV-2-T4 virus and expressed HA protein in infected CEF cells. The NP-UTR facilitated the expression and secretion of HA protein in cells infected with rAPMV-2-NPUTR-HA. Animal studies demonstrated that immunization with rAPMV-2-NPUTR-HA elicited effective H9N2-specific antibody (6.14 ± 1.2 log2) responses and conferred complete immune protection to prevent viral shedding in the oropharyngeal and cloacal swabs from chickens challenged with H9N2 virus. This study suggests that our recombinant APMV-2 virus is safe and immunogenic and can be a useful tool in the combat of H9N2 outbreaks in chicken.

Effect of humic acid and organic acids, alone or in combination, on blood biochemical constituents and humoral immune response in broiler chickens

This study was conducted to investigate the efficacy of humic acid (HA) and organic acids (OA) alone or in combination (HA-OA) on feed conversion ratio, mortality, antibody responses to infectious bronchitis virus (IBV) and Newcastle disease virus (NDV), and plasma biochemical constituents in broiler chickens. For this purpose, a total of 2,100 one-day-old mix-sexed broiler chickens were randomly allotted to 4 treatments with 5 replicate pens. Each pen holding 105 broiler chickens was used as an experimental unit. Broiler chickens of the control treatment were fed with basal diet. The 3 other treatments were: 0.1% HA, or 0.02% OA, or both 0.1% HA-0.02% OA. On d 16, 26, and 33, a sample of 30 broiler chickens from each treatment were randomly selected and blood samples were collected to determine plasma biochemical constituents and antibody responses to IBV and NDV. Antibody responses were measured by enzyme-linked immune-sorbent assays. There was no difference in the feed conversion ratio and mortality among experimental treatments. Antibody titers against NDV and IBV were increased in broiler chickens fed with HA-OA supplemented diet compared to OA treatment at d 16 (P < 0.05). Dietary supplementation of HA increased antibody titers against IBV at d 26 (P < 0.05). Dietary supplementation of HA-OA maintained anti-NDV maternal antibody titers at d 16 compared to d 1. Amount of anti- NDV antibody was increased at d 33 compared to d 16 in broiler chickens fed the diet supplemented with 0.02% OA (P < 0.05). The HA, OA, or HA-OA diets did not affect the plasma biochemical concentrations (creatinine, total protein, glucose, cholesterol, triglyceride, aspartate aminotransferase, Ca, P, Na, K, and Fe). It was concluded that the inclusion of HA in combination with OA in broiler chickens’ diets improved antibody response against NDV and IBV at d 16 without remarkable change in blood biochemical constituents. Therefore, HA-OA combination could be used as a functional feed additive in broiler chickens.