Disease Virus Antibodies Research Articles

Effects of Bacillus methylotrophicus SY200 Supplementation on Growth Performance, Antioxidant Status, Intestinal Morphology, and Immune Function in Broiler Chickens.

The present study was focused on evaluating the effects of Bacillus methylotrophicus SY200 in broiler production. A total of 120 healthy7-day-old broiler chicks were randomly assigned to four dietary treatments, which included basal diet supplemented with 0%, 0.10%, 0.25%, or 0.50% (w/w) B. methylotrophicus SY200 preparation (1.0 × 109 cfu/g), regarded as negative control group (NC), low-dose group (BML), medium-dose group (BMM), and high-dose group (BMH), respectively. Each treatment was fed the corresponding experimental diet for 35 days. Results showed that dietary supplementation of B. methylotrophicus SY200 could improve broiler weight gain, especially the finisher phase. Further studies suggested that a certain amount of B. methylotrophicus SY200 enhanced the broiler antioxidant status and improved the morphological development of jejunum. Besides, dietary supplementation of B. methylotrophicus SY200 especially in 0.50% levels significantly increased the relative weight of immune organs and Newcastle disease virus antibody titer, similarly, increased mRNA expression levels of claudin-1, claudin-3, zonula occluden-1, and zonula occluden-2 were observed in the jejunum of BMM group. Moreover, B. methylotrophicus SY200 also showed beneficial effects in improving broilers microbiota homeostasis by increasing the number of beneficial bacteria. Conclusively, B. methylotrophicus SY200 could effectively improve the antioxidant status, modulate the intestinal structure, enhance the intestinal mucosal barrier function, and regulate the immune function of broilers, which finally improves the performance of the chicken in the finisher period.

Serological investigation of low pathogenic avian influenza and Newcastle disease virus antibodies in Japanese quails, 30 village weavers and one laughing dove in two states of Nigeria

BackgroundIn spite of efforts to control avian influenza (AI) and Newcastle disease (ND) over decades, circulation of the viral causative agents among domestic and feral birds is considered implicated factors for the intermittent outbreaks of AI and ND among domesticated birds as well as commercial poultry flocks in Nigeria. In this study, sera from domestic (Japanese quails) and peri-domestic birds including laughing dove and village weavers were screened for antibodies to low pathogenic AI virus (LPAIV) and ND virus (NDV).MethodsA competitive ELISA was used to detect anti-AI virus antibodies in the sera of 101 unvaccinated Japanese quails, 30 village weavers and one laughing dove caught for human consumption in Oyo and Osun states, Nigeria. Hemagglutination-inhibiting (HI) antibodies against LPAIV were then detected in the ELISA-positive sera using H3N8, H5N2 and H9N7 subtype-specific antigens. Also, antibodies to NDV were detected and quantified in the sera using HI test.ResultsSeroprevalence of NDV antibodies from tested quail sera was 12.9% (13/101), while AI was 18.8% (19/101) with detection of anti-LPAIV H3N8, H5N2 and H9N7 antibodies. The laughing dove serum was positive for NDV and anti-LPAIV H9N7 antibodies while all sera from village weavers had no detectable LPAIV antibodies, but 26.7% (8/30) were positive for NDV antibodies.ConclusionsThis study provides serologic evidence of infection with LPAIV H3N8, H5N2 and H9N7 as well as Newcastle disease in domestic and peri-domestic birds in southwest Nigeria and highlights the potential role of these birds in the epidemiology of AI and ND.

Serological, virological and molecular diagnosis of an outbreak of lumpy skin disease among cattle in Butana area, Eastern Sudan.

BackgroundLumpy skin disease (LSD) is a highly infectious disease of cattle caused by a virus of the Poxviridae family, genus Capripoxvirus. The disease has great economic effects on the global cattle industry. In this study, an outbreak of LSD among cattle which occurred in Nahr Atbara and Halfa El Jadida locations in Butana area, Kassala State in November, 2020 is described.MethodsLumpy skin disease virus (LSDV) antibody and nucleic acid were detected in specimens (n = 50) using enzyme‐linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR).ResultsThe virus was isolated on the chorioallantoic membrane (CAM) of embryonated chicken eggs and identified by PCR. The number of animals at risk was 295 with a morbidity rate of 4.1% and a mortality rate of 2.4%.ConclusionsLSDV was diagnosed for the first time in the Butana region, Kassala State, Eastern Sudan in 2020.

Dim blue light colour reduces the activities and improves the performance of Indian River broilers under Egyptian conditions

Poultry producers accustomed to use light colours in broiler production as atrial to increase their productivity, especially in the developing countries to cover the animal protein gap. This experiment was planned to study the effect of different blue light colour intensities (high, medium and dim) on a recently imported Indian River (IR) broilers to Egypt. In this study, 270 one-day old Indian River broiler chicks were used. The birds were exposed to high blue light intensity (HBLI), medium blue light intensity (MBLI) and dim blue light intensity (DBLI), through a monochromatic lighting system that was installed in different rooms for 24 hours daily. The birds were randomly divided and housed into three well controlled pens of 5.46 m2 with three replicates of 30 each using a density of 17 birds/m2 in the room. The results showed that the broilers reared under DBLI had a significantly (p< 0.05) higher body weight, body weight gain, Newcastle disease virus antibody titer and foot pad dermatitis with obviously, economic Feed conversion ratio (FCR) and low activities and heterophyil/lymphocyte ratio in comparing with (MBLI) and (HBLI). In conclusion, poultry producer can use dim blue light in their farms to reduce the activities and increase the productivity of the birds.

Influence of environmental enrichment on circulating white blood cell counts and behavior of female turkeys

Under commercial conditions turkeys are housed in large groups in poorly structured environments. This leads to stress and subsequently to pecking and cannibalism. Environmental enrichment is suggested to reduce stress and feather pecking, thus leading to an increase of the overall flock health. However, the effect of increasing age on the use of enrichment elements and on the behavior repertoire as well as its correlation with health parameters has scarcely been studied. Therefore, our objective was to investigate the influence of environmental enrichment on the behavioral repertoire and on health parameters of turkeys. In 3 consecutive trials, female turkeys were housed up to 12 wk either in an unstructured (control group) or enriched environment (EE group) featuring elevated plateaus at different levels (“turkey tree”). Behavior parameters, clinical health, and immune parameters were determined at selected time points. The percentage of birds using the turkey tree increased with age up to 55 to 77% at 22 to 30 d post hatch (dph). Thereafter, the number of birds located on the turkey tree decreased to 25 to 32% at 73 to 79 dph. Feather pecking and fighting was significantly lower in the EE group compared to the control group in 2 and 3 trials, respectively (P < 0.05). The integrity of feathers and integument, scored in the head/neck, wing, and tail regions was repeatedly better in the EE birds compared to control birds at most investigated time points (P < 0.05), suggesting a reduction in stress related aggression by the use of the turkey tree. Head pecking, running and flying activity, foraging, and preening were overall comparable between the EE and the control group (P > 0.05). Humoral immunity as determined by vaccination-induced anti-Newcastle disease virus antibody titers was not affected by the turkey tree use. The flow cytometric evaluation of blood monocyte and T-lymphocyte numbers showed no repeatable difference between control and EE groups. Interestingly, compared to the control groups, EE birds displayed significantly higher numbers of circulating MHC class II+ lymphocytes and lower numbers of thrombocytes at various time points compared to controls (P < 0.05). This study provides clear evidence that environmental enrichment with plateaus not only leads to an altered behavioral repertoire but also modifies some of the investigated immune parameters, implying that EE may have a modulatory effect on turkeys’ immunity and overall fitness. Further studies are needed to understand the correlation between behavior and health parameters in birds more closely.

The Effect of the Antimicrobial Peptide Plectasin on the Growth Performance, Intestinal Health, and Immune Function of Yellow-Feathered Chickens.

The goal of the study was to test the effects of an antibiotic substitute, plectasin, on the growth performance, immune function, intestinal morphology and structure, intestinal microflora, ileal mucosal layer construction and tight junctions, ileal immune-related cytokines, and blood biochemical indices of yellow-feathered chickens. A total of 1,500 one-day-old yellow-feathered chicks were randomly divided into four dietary treatment groups with five replicates in each group and 75 yellow-feathered chicks in each replication, as follows: basal diet (group A); basal diet supplemented with 10 mg enramycin/kg of diet (group B), basal diet supplemented with 100 mg plectasin/kg of diet (group C), and basal diet supplemented with 200 mg plectasin/kg of diet (group D). It was found that the dietary antimicrobial peptide plectasin could improve the ADG and had better F/G for the overall period of 1–63 days. Dietary plectasin can enhance H9N2 avian influenza virus (AIV) and Newcastle disease virus (NDV) antibody levels of yellow-feathered chickens at 21, and 35 days of age. Dietary plectasin can enhance the intestine structure, inhibit Escherichia coli and proinflammatory cytokines in the ileum, and ameliorate the blood biochemical indices of yellow-feathered chickens at 21 days of age. This study indicates that the antimicrobial peptide plectasin has beneficial effects on the growth performance, intestinal health and immune function of yellow-feathered chickens.

Development and Validation of Confirmatory Foot-and-Mouth Disease Virus Antibody ELISAs to Identify Infected Animals in Vaccinated Populations.

In foot-and-mouth disease (FMD)-endemic countries, vaccination is commonly used to control the disease, whilst in FMD-free countries, vaccination is considered as an option, in addition to culling the infected and in contact animals. FMD vaccines are mainly comprised of inactivated virions and stimulate protective antibodies to virus structural proteins. In contrast, infection with FMD virus leads to virus replication and additional antibody responses to viral nonstructural proteins (NSP). Therefore, antibodies against NSPs are used to differentiate infection in vaccinated animals (DIVA), in order to estimate the prevalence of infection or its absence. Another advantage of NSP antibody tests is that they detect FMD infection in the field, irrespective of the serotypes of virus in circulation. In cattle, the NSP tests that target the 3ABC polyprotein provides the highest sensitivity, detecting up to 90% of vaccinated animals that become carriers after exposure to infection, with a specificity of around 99%. Due to insufficient diagnostic sensitivity and specificity, detection of a low level of infection is difficult at the population level with a high degree of confidence. The low level of non-specific responses can be overcome by retesting samples scored positive using a second confirmatory test, which should have at least comparable sensitivity to the first test. In this study, six in-house tests were developed incorporating different NSP antigens, and validated using bovine sera from naïve animals, field cases and experimentally vaccinated and/or infected animals. In addition, two (short and long incubation) new commercial NSP tests based on 3ABC competitive blocking ELISAs (ID Screen® FMD NSP Competition, IDvet, France) were validated in this study. The two commercial ELISAs had very similar sensitivities and specificities that were not improved by lengthening the incubation period. Several of the new in-house tests had performance characteristics that were nearly as good as the commercial ELISAs. Finally, the in-house tests were evaluated for use as confirmatory tests following screening with the PrioCHECK® and ID Screen® FMDV NS commercial kits, to assess the diagnostic performance produced by a multiple testing strategy. The in-house tests could be used in series (to confirm) or in parallel (to augment) with the PrioCHECK® and IDvet® FMDV NS commercial kits, in order to improve either the specificity or sensitivity of the overall test system, although this comes at the cost of a reduction in the counterpart (sensitivity/specificity) parameter.

Effects of health related farm-level factors on skin size and quality in commercial mink (Neovison vison) production

This study investigated the potential effects of management and health related factors on the productivity in the commercial mink production, during 2015−2018. Data were available from the database at Kopenhagen Fur, the national veterinary prescription database, VetStat, and the laboratory database at the Center for Diagnostics, Technological University of Denmark. A cross-sectional study, including 1.464 min. farms grouped into 1.187 epidemiological units, was applied. Data were analyzed in two models with different outcomes representing productivity on the mink farms, namely skin size and economical value (value sum) of the produced skin. The studied risk factors included use of vaccines and antibacterials, herd size, associated feed producer, purchases and sales of live animals, breeding results (litter size after weaning), Aleutian mink disease virus antibody (AMDV status) and stamping out, and laboratory test results.Vaccination against mink enteritis parvovirus and high breeding results were found to have a positive association with both outcomes, skin size and value sum. Both outcomes also varied significantly between farm clusters associated with different feed producers. Significant effects of antibacterial treatment were found, but the results were complex with both positive and negative associations with the outcome variables, depending on season and interactions with feed producer. Positive effects on antibacterial prescription on skin size were observed, except for farms associated with two small feed producers, known to have a variable microbiological feed quality. In farms receiving feed of very high quality, the positive effect of antibacterial prescription was marginal. ConclusionsThe use of mink data has allowed us to assess the impact of feed quality as well as antibacterial prescription on productivity. The results showed a positive quantitative effect of vaccination against mink enteritis parvovirus on skin size and value, with an optimal effect by vaccination of the whole litter. Antibacterial prescription in the growth period, particularly around weaning, was found to have a positive quantitative effect on productivity in some farms, and the results suggest that the effect was associated with the feed quality. Use of antibacterials to counteract negative effects of low feed quality is not in accordance with principles for prudent use of antibacterials.

A Duplex Fluorescent Microsphere Immunoassay for Detection of Bluetongue and Epizootic Hemorrhagic Disease Virus Antibodies in Cattle Sera.

Bluetongue virus (BTV) causes internationally reportable hemorrhagic disease in cattle, sheep, and white-tailed deer. The closely related, and often co-circulating, epizootic hemorrhagic disease virus causes a clinically similar devastating disease in white-tailed deer, with increasing levels of disease in cattle in the past 10 years. Transmitted by Culicoides biting midges, together, they constitute constant disease threats to the livelihood of livestock owners. In cattle, serious economic impacts result from decreased animal production, but most significantly from trade regulations. For effective disease surveillance and accurate trade regulation implementation, rapid, sensitive assays that can detect exposure of cattle to BTV and/or EHDV are needed. We describe the development and validation of a duplex fluorescent microsphere immunoassay (FMIA) to simultaneously detect and differentiate antibodies to BTV and EHDV in a single bovine serum sample. Performance of the duplex FMIA for detection and differentiation of BTV and EHDV serogroup antibodies was comparable, with higher sensitivity than commercially available single-plex competitive enzyme-linked immunosorbent assays (cELISA) for detection of each virus antibody separately. The FMIA adds to the currently available diagnostic tools for hemorrhagic orbiviral diseases in cattle as a sensitive, specific assay, with the benefits of serogroup differentiation in a single serum sample, and multiplexing flexibility in a high-throughput platform.

Avian orthoavulavirus 1 (Newcastle Disease virus) antibodies in five penguin species, Antarctic peninsula and Southern Patagonia.

Avian orthoavulavirus 1 (AOaV-1) causes Newcastle disease, one of the most important and contagious infections in poultry, where migratory birds can play a key role as a reservoir. Seven hundred and seven serum samples were collected from five penguin species (King, Magellanic, Gentoo, Chinstrap and Adelie penguins) in the Antarctic and Sub-Antarctic zones. Using a competitive ELISA to detect antibodies against AOaV-1, we identified positive individuals in all penguin species. The Magellanic penguin showed the highest seropositivity rate (30.3%), suggesting it could be a natural reservoir of this virus. At the Antarctic zones, Chinstrap penguin showed the highest occurrence (7.5%). Interesting, positive sera was only obtained in Sub-Antarctic and Northern zones at the Antarctic peninsula, no seroreactivity was observed in Southern locations. Further studies are needed to establish the role of these penguin species in the epidemiology of the AOaV-1 and determine the effects of this virus in these populations.

Spatial Distribution and Seroprevalence of Newcastle Disease in Kaduna State, Nigeria

Abstract Newcastle disease is one of the greatest constraints to the development of poultry production in Nigeria. In this study, the spatial distribution of Newcastle disease antibodies was determined using the Geographic Information System. A total of 400 serum samples were collected from chickens in districts around Kaduna Metropolis and screened for Newcastle disease virus antibodies using the haemagglutination inhibition test done according to the procedure of OIE (2002). The spatial distribution demonstrated that the highest antibody titre level for Newcastle disease was closely associated with communities that were at entry points (Zaria— Kaduna road; Nnamdi Azikiwe bypass road; Television garage; Abuja—Kaduna expressway and Kachia road) to the metropolis and houses that are closely situated near live bird markets signifying the importance of bird movements in the spread of the disease. About 31 % (124 of 400) of chickens had antibodies to Newcastle disease virus, with exotics breeds (32.0 %) with more Newcastle disease virus antibodies than local breeds (29.8 %). The Newcastle disease prevalence was 33.9 % (39 out of 115), 31.8 % (41 out of 129) and 28.2 % (44 out of 156) for Kaduna North, Kaduna South and Chikun Local Government Areas (LGA), respectively. A Newcastle disease prevalence of 29.8 % (54 out of 181) was recorded in the local chickens, while 32.0 % (70 out of 219) was obtained from the exotic chickens.

SEROLOGICAL SURVEY OF INFECTIOUS BURSAL DISEASE ANTIBODY IN LOCAL CHICKEN

Serological evidence for infectious bursal disease virus antibody in local chicken in Ago-Iwoye area of Ogun State was detected using agar gel precipitation test. 51 out of the 98 sera samples tested were positive for precipitating antibody against infectious bursal disease.

Newcastle disease virus antibodies in apparently healthy commercial layers in Abeokuta, Ogun state, Nigeria

Several authors have worked on Newcastle Disease (ND) with respect to the incidence, prevalence and epizootiology of the disease and the antibody status in non-vaccinated birds in Nigeria. However, current information on the antibodies of the Newcastle Disease virus in apparently healthy commercial poultry birds with known vaccination records in Abeokuta Metropolis is scanty. This study was conducted, using Heamagglutination Inhibition assay (HI) technique, to detect Newcastle Disease virus (NDV) antibodies in routinely vaccinated commercial poultry birds in the 3 Local Government Areas (LGAs) of Abeokuta that form the Abeokuta metropolis. Haemagglutinating NDV antibodies were detected in the apparently healthy layers thus indicating a widely circulating NDV in areas. A potency test of the vaccines used on the farms was determined using Heamagglutination test and their values ranged between 2 and 2 . The sero-prevalence of NDVantibodies in the 3 LGAs showed there was no significant difference (p &gt;0.05). Of the 120 sera tested, 82 (68.33%) had detectable NDV antibodies but only 81.67% had HI protective titre of &gt; 2 and 18.33% had low seroconversionwith titre 2 or less.

Aleutian mink disease: Spatio-temporal variation of prevalence and influence on the feral American mink.

Pathogens are one of the factors driving wildlife population dynamics. The spread of pathogens in wildlife is currently highly related to the transmission of pathogens from farmed animals, which has increased with the constant development of farming. Here, we analysed the spatio‐temporal variation in the prevalence of Aleutian mink disease virus (AMDV) antibodies in feral American mink (Neovison vison) populations in Poland (1,153 individuals from nine sites) in relation to mink farming intensity. AMDV was detected in feral mink at all study sites and the prevalence ranged from 0.461 in the northern region to 0.826 in the western region. Mink males and adults were infected more often than females and subadults; the infection was also more frequent during the mink breeding season than during non‐breeding. The prevalence of AMDV changed non‐linearly in consecutive years and the peak of prevalence was every 3–4 years. The predicted AMDV prevalence was low at sites where the number of farmed mink was also low and increased linearly with the increase in the number of mink kept on farms. The predicted AMDV prevalence at sites with low mink farming intensity strongly varied between years, whereas at sites with high mink farming intensity, the predicted prevalence did not change significantly. AMDV infection affected the mink's body condition and caused an increase in the size of the spleen, liver and kidneys. This study shows that Aleutian mink disease strongly affects feral mink but the spatio‐temporal variation of its prevalence is complex and partly related to the transmission of the virus from farmed mink to feral populations. The study highlights the complexity of AMDV circulation in feral mink populations and implicates a potential spillover of the virus to native species.

Spatial distribution and seroprevalence of Newcastle disease (ND) in Kaduna State, Nigeria

Background: Newcastle disease (ND) is a major viral disease of economic importance in poultry and rated as one of the greatest constraints to the development of poultry production in Nigeria. This study aimed to determine the spatial distribution and seroprevalence of Newcastle in Kaduna State, Nigeria. Methods and materials: In this study, spatial distribution of ND antibodies was determined using the Geographic Information System (GIS). A total of 400 serum samples were collected from chickens in districts around Kaduna Metropolis and screened for Newcastle disease virus (NDV) antibodies using haemagglutination inhibition tested according to the procedure of OIE (2002). Results: Spatial distribution showed that the highest antibody titre of Newcastle disease was closely associated with communities that were at entry points (Zaria – Kaduna road; Nnamdi Azikiwe bye-pass road; Television garage; Abuja – Kaduna expressway and Kachia road) to the metropolis and houses that are closely situated near live bird markets signifying the importance of bird movement in the spread of the disease. There were variations in poultry distribution patterns between various communities. Poultry sampled were more concentrated in communities that have a cluster settlement pattern, while communities that are having a linear settlement pattern have low population of poultry. Antibody titre level of Newcastle disease was higher in communities that are at entry points to the metropolis and. About 31% (124 of 400) of chickens had antibodies to NDV, with exotics breeds (32.0%) with more NDV antibodies than local breeds (29.8%). The ND prevalence was 33.9% (39 out of 115), 31.8% (41 out of 129) and 28.2% (44 out of 156) for Kaduna North, Kaduna South and Chikun Local Government Areas respectively. Newcastle disease prevalence of 29.8% (54 out of 181) was recorded in local chickens while 32.0% (70 out of 219) was obtained from exotic chickens. Conclusion: Newcastle disease is endemic in both local and exotic poultry with a higher spatial distribution around entry points into Kaduna Metropolis. There is a need for awareness and routine vaccination of poultry against newcastle disease especially around bordering communities.

Epizootic situation concerning especially dangerous viral infections among birds of South Ukraine

Aim of the work was monitoring of especially dangerous and economically significant poultry infections in the South of Ukraine. The research was conducted at the Odessa Research Station of the National Scientific Center “Institute of Experimental and Clinical Veterinary Medicine” and in the Testing Center of the Odessa Regional State Laboratory of the State Service of Ukraine on Food Safety and Consumer Protection. The corpses of dead birds were subjected to autopsy; meanwhile biological material was picked up for research. Serological tests for Newcastle disease were performed in HIT with a virus dose of 4 UHA in a titer of 1:8 and higher. In addition to common bacteriological studies the presence of bacterial associates was determined. Serological tests of 365 samples of blood from poultry from 73 settlements, 16 samples from wild and 18 samples from synanthropic birds of Odessa Region, did not reveal antibodies to avian influenza virus of subtype H5. The presence of the formed group immunity against the causative agent of Newcastle disease was detected in the farmsteads of 118 settlements and in 10 industrial poultry farms (seropositivity is 80–100%). Antibodies against the pathogen of Newcastle disease in the blood sera from wild birds from Odessa Region were not detected. In the summer-autumn season, some outbreaks of the Newcastle disease among ornamental pigeons were detected in three farms of two settlements. Mortality was 50–70%. Studying of 15 blood samples from pigeons detected antibodies to Newcastle disease virus (antibody titer 4.0–7.1 log2). Autopsy of 28 poultry carcasses revealed changes characteristic of infectious laryngotracheitis of chickens, as well as some diseases of bacterial (tuberculosis, pasteurellosis, escherichiosis) and protozoan (trichomoniasis of chickens) etiology. Monitoring data on particularly dangerous viral infections of poultry in the South of Ukraine indicate the stability of the epizootic situation. The absence of hemagglutinating antibodies to avian influenza virus of the H5 subtype in the populations of the studied birds of different species and the presence of the formed group immunity against the Newcastle disease pathogen were established; seropositivity is 80–93 %. The circulation of Newcastle disease virus among ornamental pigeons has been established

Effects of cage type on performance, welfare, and microbiological properties of laying hens during the molting period and the second production cycle.

As most of the unenriched cages will soon switch to enriched cages, it is important to characterize all the effects in the laying hens for sustainable production. Laying hens can be used in several production periods by applying molting. The aim of this study was to determine the cage type (unenriched and enriched) on performance, welfare, and microbiological properties of laying hens during the molting period and the second production cycle. Overall, 840 brown laying hybrids were used in the experiment. Laying hens were reared on two different cage types (unenriched cage (UEC) and enriched cage (EC)) in the same poultry house. When the hybrids were 75weeks old, they were subjected to force molting with whole grain barley. Performance, welfare, microbiological, and serological data of laying hens were obtained from 73 to 107weeks of age. Egg production, egg weight, feed conversion ratio, breaking strength, albumen and yolk index, Haugh unit, feather condition, and breaking force of femur and metatarsus were better in the post-molting period. However, keel bone deformities and Newcastle disease virus antibody titers are the worst in the post-molting period. Stiffness of femur and metatarsus was increased with period. These results indicate that necessary precautions should be taken against the problems that may occur in the direction of bone and health. During the molting period, hens kept in EC had lower egg production but they returned to egg production at a high rate. EC type had a positive effect on egg production, feed conversion ratio, feather and foot condition, and breaking force of metatarsus.

Immunosensor-based rapid quantitative detection of Newcastle disease virus antibodies using innovative gold immunochromatographic assay.

A novel quantitative method for rapid Newcastle disease virus (NDV) antibody detection was developed based on an innovative gold immunochromatographic assay with a quantitative immunosensor. NDV antibody-detecting test strips containing a two-reaction system and double-test lines (T1, T2) were prepared. The test results were judged according to the signal ratio between the test and control lines as measured by the quantitative immunosensor. The minimum detection limit of the test strips for NDV antibodies was 22 titres. In addition, the assay was highly specific because only NDV antibodies produced visible test lines on the strip. The clinical application of the strips was tested by detecting NDV antibodies in 506 serum samples collected from chickens. The results showed a coincidence of 92·49% with those of the haemagglutination inhibition assay. The strips were successfully prepared and showed high specificity towards NDV, sensitivity and stability. This study describes a new method for detection of NDV antibody and provides a reference basis for rapid and quantitative monitoring of NDV antibodies. This new method overcomes the limitation of the existing colloidal gold immunochromatography, which only produces qualitative or semi-quantitative results.

Changes in the Percentages of B- and T-Lymphocytes and Antibody Titres in Laying Hens Infested with Dermanyssus gallinae-A Preliminary Study.

Simple SummaryDermanyssus gallinae, a hematophagous ectoparasite, adversely affects the health status of laying hens, leading to reduced egg production and significant economic losses in commercial poultry farms. The aim of this study was to determine the effect of D. gallinae on the immunological parameters (three lymphocyte subpopulations) and post-vaccination antibody titres (against most important avian pathogens) in layer hens during the egg production cycle. A total of 80 blood samples were collected at four time-points (B1–B4) from 10 Hy-Line Brown hens naturally infested with D. gallinae, which were randomly selected from a commercial layer farm. The infestation was monitored and treated twice with Biobeck PA 910 (active ingredient AI – silicon dioxide). The samples were collected before and after each treatment. The percentages of subpopulations of B cells and helper (Th) and cytotoxic (Tc) T cells were determined by flow cytometry. Antibody titres were determined by the immunoenzymatic method. The percentage of Th cells and post-vaccination anti-infectious bronchitis virus (anti-IBV) and anti-Newcastle disease virus (anti-NDV) antibodies decreased significantly at the second infestation peak when the number of parasites was twice higher than at the first infestation peak. There were non-significant correlations between the number of mites and antibody titres. These findings suggested that D. gallinae might inhibit humoral immune responses since the percentages of B cells and Th cells were negatively correlated with the number of mites. The percentage of Tc cells was positively correlated with the number of mites, which indicated that D. gallinae could stimulate cellular immune responses in infested laying hens. However, further research is needed to determine whether D. gallinae suppresses the production of vaccine-induced antibodies.(1) Background: Dermanyssus gallinae, a hematophagous ectoparasite, adversely affects the health status of laying hens, leading to reduced egg production and significant economic losses in commercial farms. The aim of this study was to determine the effect of D. gallinae on the development of post-vaccination immune responses in layer hens. (2) Methods: A total of 80 blood samples were collected at four time-points (B1–B4) from 10 Hy-Line Brown hens, randomly selected from a commercial layer farm. The flock was naturally infested with D. gallinae and treated twice with Biobeck PA 910 (AI silicon dioxide). The samples were collected before and after each treatment. The percentages of IgM+ B cells, CD3+/CD4+ T cells and CD3+/CD8a+ T cells were determined by flow cytometry; the titres of antibodies against avian encephalomyelitis, infectious bronchitis virus, Newcastle disease virus, Ornithobacterium rhinotracheale, reticuloendotheliosis virus and avian reovirus were determined by the immunoenzymatic method. (3) Results: The percentage of Th cells and post-vaccination anti-IBV and anti-NDV antibodies decreased significantly at the second infestation peak when the number of parasites was twice higher than at the first infestation peak. Non-significant negative correlations were found between the number of mites and the percentage of B cells (R = −0.845, p > 0.05) and between the number of mites and the percentage of Th cells (R = −0.522, p > 0.05), and a significant positive correlation was noted between the number of mites and the percentage of Tc cells (R = −0.982, p < 0.05). There were non-significant correlations between the number of mites and antibody titres. (4) Conclusion: The present findings suggested that D. gallinae might inhibit immune responses since the percentages of B cells and Th cells were negatively correlated with the number of mites. The percentage of Tc cells was positively correlated with the number of mites, which indicated that D. gallinae could stimulate cellular immune responses in infested laying hens. However, further research is needed to determine whether D. gallinae suppresses the production of vaccine-induced antibodies.

Effects of fermented feed on growth performance, immune response, and antioxidant capacity in laying hen chicks and the underlying molecular mechanism involving nuclear factor-κB

This study investigated the effects of fermented-feed diets on growth performance, immune status, and antioxidant responses in laying hen chicks and the underlying molecular mechanism, specifically, the role of the nuclear factor-κB (NF-κB) signaling pathway. A total of 80 healthy 14-day-old laying hen chicks were randomly divided into 4 treatments: basal diet (CON); basal diet supplemented with 7.5% fermented feed (FD); FD diet plus the NF-κB inhibitor BAY 11-7082 (FD + BAY); and FD diet plus the NF-κB inhibitor JSH-23 (FD + JSH). The NF-κB inhibitors were administered by intraperitoneal injection. The experiment lasted 21 D. Fermented feed supplementation significantly increased the body weight and average body weight gain of laying hen chicks but significantly decreased the feed conversion ratio. Additionally, fermented feed supplementation significantly increased mitogen-activated T-cell and B-cell proliferation in the peripheral blood, as well as elevated the serum concentrations of interleukin (IL)-1, IL-2, IL-4, IL-6, and tumor necrosis factor (TNF-α); however, NF-κB inhibition significantly reduced T-cell proliferation and serum IL-1, IL-6, and TNF-α levels. The levels of IgA, IgG, IgM, and Newcastle disease virus antibody in the serum were significantly increased by the addition of fermented feed. Furthermore, fermented feed supplementation significantly improved antioxidant function, as indicated by the increases of total antioxidant capacity, total superoxide dismutase activity, and glutathione peroxidase activity and the decrease of malonaldehyde level. However, NF-κB inhibition reversed these changes. Western blot analysis showed that fermented feed treatment increased splenic IκB kinase β and NF-κB protein levels, whereas these increases were prevented by NF-κB inhibition. In conclusion, fermented feed improves the growth performance, immune function, and antioxidant capacity of laying hen chicks. Fermented feed-induced modulation of T-cell proliferation, T helper type 1 and T helper type 2 cytokine production, and antioxidation is associated with NF-κB activation.