Biomedical subjects

C R Boyle

Publications and source records attributed to C R Boyle.

41 records · Page 3Linked to original sources

PubMedDate not supplied

Effects of modified-live infectious bronchitis virus vaccines on the head-associated lymphoid tissue (HALT).

Specific-pathogen-free (SPF) leghorn chicks were inoculated with different modified-live infectious bronchitis virus (IBV) vaccines to determine if the vaccines interfered with immune competence of the head region. A total of 16 vaccines were evaluated comprising nine Massachusetts, three Arkansas, two Holland, one Florida, and one combination vaccine (containing both Connecticut and Massachusetts). Chicks were vaccinated when they were 4 weeks, 2 weeks, or 1 day of age. When all chickens were 4 weeks 3 days of age, their glands of Harder (GH) were assayed for the ability to respond to antigenic stimulation. Tissues from chicks given GH-depressing and non-GH-depressing vaccines were also collected and scored for histological changes in the head-associated lymphoid tissue (HALT) sites and the trachea. All 16 vaccines depressed the GH response to antigenic stimulation when given to 4-week-old chicks. Six of these vaccines (two Massachusetts, two Arkansas, and two Holland) also depressed the GH response when given to 2-week-old chicks, and one, an Arkansas vaccine, depressed the GH response when given to 1-day-old chicks. The main histological changes associated with the vaccines were increases in lymphocyte populations in the nasal mucosa, eyelid, and, for some, the lacrimal gland and the GH. In addition, lymphoid follicles were increased in the eyelid, to a lesser degree in the GH, and occasionally in the trachea. No relationship was found between histologic changes and vaccine-induced suppression of the GH response.

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PubMedDate not supplied

Influence of site of inoculation of inactivated vaccines of the immune response in chickens.

Commercial caged laying chickens were primed with live Newcastle disease/infectious bronchitis (ND/IB) combined vaccines by spray method at 2, 5, and 9 weeks of age. At 16 weeks of age, birds were inoculated with inactivated ND/1B combined vaccines either intramuscularly, in the breast, wing, or thigh, or subcutaneously, at the back of the neck. An enzyme-linked immunosorbent assay was used to measure serum antibodies to ND virus and IB virus in experimental chickens before injection and every 8 weeks postinjection until 48 weeks of age. The subcutaneous or wing muscle routes of injection resulted in higher antibody titers to NDV through 16 weeks postinjection; however, variations in antibody titers existed among the groups owing to vaccine priming before injection and therefore were not considered important. No differences were found in antibody titers to IB virus among the various groups because of site of injection. Granulomatous lesions were encountered most frequently in birds inoculated in the wing muscle.

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PubMedDate not supplied

Attempts to reproduce a runting/stunting-type syndrome using infectious agents isolated from affected Mississippi broilers.

Various organisms, including 12 aerobic and 2 anaerobic bacteria, an infectious bronchitis virus (IBV), a reovirus, and 2 bacteriophages, were isolated from intestinal tracts of commercial broiler chicks undergoing a runting/stunting-type condition. In a series of trials, these agents were given alone and in combination to 1-day-old chicks in an attempt to reproduce the field condition. Because the agents were isolated and evaluated over time, an augmented designs variation of the analysis of variance proved particularly useful in analyzing the data collected and minimizing bird usage. Chicks inoculated with tryptose phosphate broth served as negative controls, and those inoculated with the original intestinal tract material were positive controls. Relative to the negative control chicks, body weights of the positive control chicks and of chicks inoculated with several of the agent combinations were depressed at 7, 14, and 21 days postinoculation. Common to combinations that most consistently caused weight depression were reovirus + IBV + others of the agents isolated. However, because none of the agent combinations reproduced the lethargy or dry feces seen in the positive controls, none was considered to be the ultimate cause of this particular runting/stunting-type condition. Further characterization of the disease syndrome was based on the positive control chicks. These chicks consistently had lowered body weights and transient lethargy and dry fecal pellets. Microscopic lesions consisted of lymphocytic renal and pancreatic interstitial infiltrates, dilated or cystic duodenal and jejunal crypts of Lieberkühn, increased crypt depth, and increased cellularity in the intestinal lamina propria. Electron microscopy revealed regular arrays of 26-nm viral particles, usually in association with membrane debris, in intestinal epithelial cells and crypt lumens and in intestinal and renal mesenchymal cells. These viral particles were theorized to be essential to reproduction of the complete malady seen.

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PubMedDate not supplied

Effects of Newcastle disease vaccines and Newcastle disease/infectious bronchitis combination vaccines on the head-associated lymphoid tissues of the chicken.

Ten Newcastle disease virus (NDV) and 10 NDV and infectious bronchitis virus (IBV) combination vaccines (NDV/IBV) were evaluated for their effect on the head-associated lymphoid tissue (HALT) of 2-wk-old chicks. After vaccination, the chicks were subjected to an in vivo assay that measures the ability of the gland of Harder (GH) to respond to killed Brucella abortus antigen given in the eye by titering B. abortus antibodies in the tears. Following this, several sites in the HALT and trachea were examined histologically and scored for microscopic changes. The results indicated that three of the NDV/IBV combination vaccines (one BI/Mass&Conn and two LaSota/Mass&Conn) interfered with the GH response to killed B. abortus, whereas none of the NDV vaccines did Histologically, several changes were noted in the vaccinated chicks; however, no changes in the GH were observed that could explain microscopically the GH depression. With the IBV-only vaccines reported earlier (16), and the NDV-only and NDV/IBV combination vaccines reported here, a total of 36 vaccines have been evaluated using the same testing protocol. The conclusions of these combined studies suggest that several of the modified live virus vaccines containing IBV, either alone or in combination with NDV, interfere with the ability of the GH/HALT to respond to antigenic stimulation.

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PubMedDate not supplied

The effects of F strain Mycoplasma gallisepticum, Mycoplasma synoviae, and the dual infection in commercial layer hens over a 44-week laying cycle when challenged before beginning of lay. I. Egg production and selected egg quality parameters.

In each of two trials, 160 commercial pullets were separated into four treatments with four replicates of 10 chickens in each treatment. Forty pullets were designated as controls and received no inoculation; 40 other pullets received F strain Mycoplasma gallisepticum (FMG); an additional 40 pullets received Mycoplasma synoviae (MS); and the final 40 pullets were inoculated with both FMG and MS (dual). Hen-day egg production, egg weight, eggshell strength, Haugh unit score, pimpling incidence, and blood/meat spot incidence were monitored and recorded in each trial through an entire laying cycle. No significant difference was observed among the treatments for hen-day egg production, egg weight, eggshell strength, or Haugh unit scores. Significant differences were observed for pimpling incidence among controls (1.63%), Mycoplasma gallisepticum (MG)-infected (2.09%), and dual-infected hens (2.41%). A significant difference in blood/meat spot incidence was observed between MG-infected hens (0.27%) and dual-infected hens (0.45%). Histopathologic examination of the ovary and all segments of the oviduct revealed no significant differences among the treatments. These results suggest that the majority of the hen reproductive tract functions similarly in FMG-vaccinated, MS-infected, or dual-infected hens as compared with Mycoplasma-clean hens.

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