Dietary arginine stimulates humoral and cell-mediated immunity in chickens vaccinated and challenged against hydropericardium syndrome virus.

The effects of dietary supplement of arginine on protective humoral and cell-mediated immune responses of broiler chicks vaccinated and challenged against hydropericardium syndrome virus (HPSV) were investigated and compared with those of 2 reference drugs (cyclophosphamide and cyclosporine). Percentage ratios of lymphoid organs (bursa, spleen, and thymus) to BW, postvaccination and challenge serum antibody responses to HPSV, cutaneous basophil hypersensitivity reaction, peripheral lymphoproliferation, postchallenge detection of HPSV in the tissues of infected birds, and ability of chicks to resist virulent HPSV challenge were the parameters utilized to determine the effects of arginine on protective immune responses of chicks. A total of 600 chicks were used in this study. Arginine-supplemented chicks showed significant (P < 0.05) stimulation of lymphoproliferation and cutaneous basophil hypersensitivity reactions compared with untreated control chicks. Similarly, significantly higher body and lymphoid organ weights were (P < 0.05) recorded in arginine-supplemented chicks compared with untreated control chicks. The highest survival rate was recorded in arginine-supplemented HPS-vaccinated chicks compared with immune-suppressed (cyclophosphamide- and cyclosporine-treated and HPS-vaccinated chicks) and untreated unvaccinated control chicks after virulent HPSV challenges. Postchallenge tissue samples from arginine-supplemented and HPS-vaccinated chicks yielded negligible HPSV detections by virus isolation in cell culture or PCR method, or both, compared with untreated control chicks. Thus, it was concluded that dietary supplementation of arginine had beneficial effects on humoral and cell-mediated immune responses of broiler chicks against HPSV.

Effects of salinomycin on cell-mediated immunity of broiler chickens against hydropericardium syndrome and Newcastle disease viruses.

The effects of salinomycin (SAL) on protective cell-mediated immune (CMI) responses of vaccinated and challenged broiler chicks against hydropericardium syndrome virus (HPSV) and Newcastle disease (NDV) were investigated while comparing 3 reference drugs [levamisole, cyclophosphamide (CYP), and cyclosporine (CYS)]. Peripheral lymphoproliferation, skin hypersensitivity reactions, and the ability of chicks to resist virulent HPSV and virulent NDV challenges were used to determine the effects of drugs on CMI responses in chicks. Salinomycin-medicated chicks showed significant (P < 0.05) stimulation of lymphoproliferation and nonsignificant (P > 0.05) stimulation of skin hypersensitivity reactions compared with untreated control chicks. However, skin thickness and lymphoproliferation of SAL-medicated chicks were significantly greater (P < 0.05) than those of CYP- and CYS-treated chicks. The greatest survival rate was recorded in SAL-medicated chicks compared with immune-suppressed (CYP- and CYS-treated) and untreated control chicks after virulent NDV and virulent HPSV challenges. Thus, it was concluded that SAL had beneficial effects on the CMI responses of broiler chicks against HPSV and NDV.

Effects of polyether ionophores on the protective immune responses of broiler chickens against Angara disease and Newcastle disease viruses.

Immunization against Angara disease virus (ADV), a serotype 4 avian adenovirus, and Newcastle disease virus (NDV), an avian paramyxovirus serotype 1, is the mainstay of a broiler vaccination programme, while polyether ionophores usually form an essential component of a broiler medication programme in most parts of India and Pakistan. The role of polyether ionophores in the protective immune responses of broiler chickens vaccinated and challenged with ADV and NDV was investigated. A total of 1600 birds were divided into eight groups of 200 birds each. First four groups were vaccinated against NDV and ADV, while the remaining four served as unvaccinated controls. The first 3 groups of birds were administered salinomycin, monensin and cyclophosphamide (CYP), respectively. The last group served as an untreated control. The same treatment schedule was also followed for the next four unvaccinated groups. The post-vaccination and post-challenge serological responses to NDV and ADV, body and lymphoid organ weight gains, post-challenge survival rate and detection of NDV and ADV in the tissues of infected birds were evaluated. Birds administered salinomycin showed a significant stimulation of protective immune responses against both NDV and ADV as compared to the untreated and CYP-treated birds. Monensin also enhanced the protective immune responses against both viruses but the effect was not statistically significant. Thus, it is concluded that monensin and salinomycin augment the anti-NDV and anti-ADV immune responses in broiler chickens, which supports their use in poultry flocks.

Identification of the antigenic components of the virulent Mycoplasma gallisepticum (R) in chickens: their role in differentiation from the vaccine strain (F).

The antibody response to different proteins of Mycoplasma gallisepticum (MG) was studied in chickens experimentally infected with virulent MG R strain. The chickens were challenged at 8 weeks of age by the intranasal route. Each cockerel received 1.3 X 10(6) colony-forming units (CFU). MG strains (R and F) were banded by Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE). The banding pattern was distinctively different between the two strains in the range of 92.5 to 200 kilodaltons (kD). Chicken sera collected at different times following challenge were analyzed by Western blot to determine the patterns of antibodies raised to specific MG proteins (R versus F strains). Early in infection (2 weeks postchallenge), antibodies to 60-kD and 75-kD polypeptides of MG R strain were produced. Subsequently (greater than or equal to 4 weeks postchallenge), antibodies recognized a larger number of MG antigens in both strains. The immunoblot patterns remained the same in the period 8-11 weeks postinfection in each of the two strains; however, the patterns were different when the two strains were compared. The early response recognized the 75-kD protein in the R strain while it recognized the 80-kD protein in the F strain. The late response recognized the 130-kD protein and the protein slightly heavier than 200 kD in the R strain. These two bands did not appear in the immunoblot performed against the F strain of MG. Electroeluted protein of MG R strain, namely adhesin (75 kD), showed a hemagglutination activity (HA) on chicken red blood cells. With the appearance of antibodies specific to the 60-kD and 75-kD polypeptides, there was a significant rise in hemagglutination-inhibition geometric mean titer of chicken sera.

Efficacy of infectious bronchitis virus vaccines against heterologous challenge.

Twenty-four-week-old white Leghorn layers were inoculated subcutaneously with a killed Newcastle disease-infectious bronchitis (Massachusetts type) virus (MIBV) vaccine. Twenty-eight weeks after vaccination, the birds were challenged intraocularly with the Arkansas strain of infectious bronchitis virus (AIBV) to determine the effects of heterologous virus exposure on egg production, egg quality and serum antibody response of the birds. The challenged hens laid significantly (P less than 0.005) fewer eggs than the unchallenged layers. Eggs laid by the unchallenged groups weighed significantly more (P less than 0.005) than those laid by the challenged groups. Further, the internal quality (Haugh units) and shell quality of eggs laid by the AIBV-challenged hens was significantly (P less than 0.005) inferior to those from the unchallenged hens. In addition, the AIBV-challenged hens laid more soft-shell, misshapen and small eggs than the unchallenged hens. The Arkansas serum haemagglutination inhibition (AIBV-HI) titres of AIBV challenged birds increased up to four weeks after challenge. The corresponding MIBV haemagglutination-inhibition (MIBV-HI) titres decreased during the same period. The study indicates that killed MIBV vaccine offered no protection to birds exposed to heterologous AIBV.

A dot-immunobinding assay for infectious bronchitis virus.

Common Whatman filter paper grade 1 and nitrocellulose membrane were compared for their sensitivity in a dot-immunobinding assay for detection of serum antibody titers to Arkansas avian infectious bronchitis virus (AIBV). For a blue to purple color detection, serum antibodies were bound to AIBV antigen adsorbed on the filter-paper discs or nitrocellulose membrane. Rabbit anti-chicken IgG horseradish-peroxidase (HRP) conjugate and hydrogen peroxide with 4-chloro-1-naphthol (HRP-color development reagent) were applied. The study indicates that very small amounts of antigen/antisera are needed for the dot-immunobinding assay. The test is sensitive, economical, and easy to run and can be completed within 6-8 hours.

Detection of parvoviruses in wolf feces by electron microscopy.

One hundred fifteen wolf (Canis lupus) feces were collected between 1980 and 1984 from northeastern Minnesota and were examined for canine parvovirus by negative contrast electron microscopy. Of these, seven (6%) samples revealed the presence of parvovirus. Some of these viruses were able to grow in cell cultures forming intranuclear inclusion bodies and giant cells.

Effects of avian infectious bronchitis virus (Arkansas strain) on vaccinated laying chickens.

Twenty-four-week-old white leghorn layers were inoculated subcutaneously with a killed Newcastle-infectious bronchitis (Massachusetts type) virus (MIBV) vaccine. The birds were challenged 194 days later intraocularly with Arkansas strain of infectious bronchitis virus (AIBV). The challenged hens laid significantly (P less than 0.005) fewer eggs than the unchallenged layers, and the eggs laid by the challenged groups weighed significantly less (P less than 0.001) than those laid by the unchallenged groups. Further, the internal quality (Haugh units) and shell quality of eggs laid by the challenged hens were significantly (P less than 0.005) inferior to the quality of eggs from unchallenged hens, and the challenged hens laid more soft-shelled, misshapen, and small-sized eggs than the unchallenged hens. The Arkansas serum hemagglutination-inhibition (AIBV-HI) titers of challenged birds increased continuously through 29 days post-challenge. The MIBV hemagglutination-inhibition (MIBV-HI) titers of killed-MIBV-vaccinated birds decreased during the same period. The study indicates that killed MIBV vaccine offered no protection to birds exposed to AIBV. The same vaccine was quite effective against a homologous (MIBV) virus challenge.

Antibodies to avian infectious bronchitis virus in Pakistani chickens.

Using the hemagglutination inhibition test, sera from 20 diseased and 3 apparently healthy chicken flocks in Pakistan were examined for antibodies to four types of avian infectious bronchitis virus (AIBV). These flocks were not vaccinated against AIBV. Of the 900 serum samples from diseased flocks, 78 (8.7%) had antibodies to the Massachusetts (M41) type, 23 (2.6%) to the Arkansas type and 20 (2.2%) to the Connecticut type of AIBV. None had antibodies to the JMK type. None of the sera (n = 100) from apparently healthy layers was positive to any of the four AIBV types tested. Some of the birds with antibody titers exhibited no signs of illness except that they laid pale colored eggs or had a history of poor hatchability. These results indicate that at least three AIBV types are circulating in chicken flocks in Pakistan.

Effects of infectious bronchitis virus (Arkansas strain) on laying chickens.

Seventy-seven-week-old white leghorn layers were inoculated intraocularly with the Arkansas strain of infectious bronchitis virus (AIBV) to study the effects of the virus on egg production and on antibody response of the birds. Infected hens laid fewer eggs than the controls, and those eggs weighed less than eggs laid by controls. Further, the shell quality and internal quality of eggs laid by infected birds were inferior. The serum hemagglutination-inhibition (HI) titers of infected birds increased continuously through 4 weeks postinfection; serum HI titers of the controls were negligible.