Source: VIRGINIA POLYTECHNIC INSTITUTE submitted to
MORPHOLOGICAL CHARACTERIZATION AND DIETARY CAPSAICIN POTENTIATION OF INTESTINAL IMMUNITY IN CHICKENS.
 
PROJECT DIRECTOR: McElroy, A. P.
 
PERFORMING ORGANIZATION
ANIMAL AND POULTRY SCIENCES
VIRGINIA POLYTECHNIC INSTITUTE
BLACKSBURG,VA 24061
 
NON TECHNICAL SUMMARY: Although Salmonella and coccidia present problems to the commercial poultry industry from economic, food-borne illness, or bird productivity standpoints, relatively little is understood concerning the interactions between these pathogens and the host at the level of the intestinal immune response. The purpose of this research is to describe the effector functions of mast cells and eosinophils in innate intestinal immune responses to Salmonella and coccidia in broiler chickens.
 
OBJECTIVES: Describe the response of mast cells and eosinophils in the innate intestinal inflammatory immune response to coccidia or Salmonella infection in commercial broilers. Characterize the non-specific or specific effector functions of mast cells and eosinophils in protective intestinal immune responses to secondary exposure to homologous challenges with coccidial species or Salmonella. Determine the role of mast cells or eosinophils in immunopathology of coccidia. Evaluate the effect of dietary capsaicin administration on intestinal immune responses and resistance to coccidia or Salmonella.
 
APPROACH: Naive or immunized commercial broiler chickens will be challenged with Salmonella or selected Eimeria species of coccidia. Intestinal tissue will be collected on selected days post-challenge for morphological evaluation and microbiologic culture or lesion scoring for Salmonella or Eimeria, respective to pathogen. Capsaicin will be included in commercial broiler diets for selected periods of time pre- or post-challenge. Intestinal tissues will be examined by light microscopy for alterations in structure or cellular influx and protection to infection by Salmonella or coccidial species will be evaulated by culture or lesion scoring.
 
CRIS NUMBER: 0188709 SUBFILE: CRIS
PROJECT NUMBER: VA-135638 SPONSOR AGENCY: CSREES
PROJECT TYPE: HATCH PROJECT STATUS: TERMINATED MULTI-STATE PROJECT NUMBER: (N/A)
START DATE: Jul 1, 2001 TERMINATION DATE: Jun 30, 2006

GRANT PROGRAM: (N/A)
GRANT PROGRAM AREA: (N/A)

CLASSIFICATION
Knowledge Area (KA)Subject (S)Science (F)Objective (G)Percent
311322010904.240%
311322011604.210%
313322010904.240%
313322011604.210%

CLASSIFICATION HEADINGS
KA313 - Internal Parasites in Animals
KA311 - Animal Diseases
S3220 - Meat-type chicken, live animal
F1160 - Pathology
F1090 - Immunology
G4.2 - Reduce Number and Severity of Pest and Disease Outbreaks


RESEARCH EFFORT CATEGORIES
BASIC 60%
APPLIED 40%
DEVELOPMENTAL (N/A)%

KEYWORDS: broilers; chickens; mast cells; eosinophils; capsaicin; salmonella; eimeria; coccidia; immunity; intestines; poultry diseases; immunology; animal pathology; immune response; inflammation; tissue analysis; diet; performance evaluation; infection; disease prevention; bacterial diseases (animals); host pathogen relations

PROGRESS: Jul 1, 2001 TO Jun 30, 2006
The overall objectives of this project were to evaluate immune responses of the small intestine, with specific attention to mast cells, in response to Salmonella enteritidis (SE) and selected species of Eimeria, and evaluate a natural dietary additive with potential to stimulate or potentiate these cellular responses to afford protection to chickens to these enteric pathogens. During the five years of this project, a variety of experiments were conducted to evaluate non-antibiotic alternatives for enteric disease resistance in commercial poultry, and the effect of these alternatives on intestinal integrity and immune responsiveness in the absence or presence of the pathogens were studied. We investigated the effects of dietary administration of capsaicin, the spicy and irritant component found in peppers of the plant genus Capsicum, on SE or S. typhimurium (ST) infection in broilers. Experiments indicated dietary administration of capsaicin dramatically increased resistance to Salmonella infection following oral challenge with no effect on feed consumption, feed conversion, or weight gain of birds as compared to control fed chickens. We reported that the capsaicin induced resistance was dependent on prophylactic administration of the additive, while therapeutic administration resulted in contrasting results. Based on initial observations of morphological changes in the chicken small intestine lamina propria it appeared that a capsaicin-induced change of the lamina propria, indicating a mild inflammatory response, may alter the interaction of the pathogen with the mucosal epithelium, thereby decreasing the invasiveness of the organism. Our work on this project also focused on mucosal immunity and the role it plays in controlling Eimeria in commercial poultry. We conducted numerous experiments to evaluate intestinal morphological and cellular responses to selected species of Eimeria in different lines of commercial broilers in the absence or presence of Eimeria vaccination or prophylactic chemotherapeutic feed approaches to control the pathogen. Challenge of broiler chickens with Eimeria resulted in significant increases in lamina propria thickness and increased numbers of mast cells in the ceca or ileum of the intestine. Additionally, different species, and even different isolates within species, of Eimeria resulted in significantly different morphological alterations and mast cells responses with regard to the timing or magnitude of the response. The influx of mast cells into the lamina propria of the distal ileum and ceca apparently contributed to an increase in lamina propria thickness that coincided with the peak appearance of intestinal lesions. In examining non-antibiotic approaches for Eimeria control, our research indicated a live vaccine was effective in generating intestinal immune responses to a subsequent mixed Eimeria challenge with no negative impact on intestinal integrity or bird performance. Results from experiments also provided evidence that differences exist in the intestinal response of different breeds of commercial broilers to Eimeria that could contribute to disease severity and live performance.

IMPACT: 2001-07-01 TO 2006-06-30 Relevance: Intestinal diseases present a variety of problems to the poultry industry, including economic loss, impacts on bird health or production, or potential for human health concerns; however, understanding of immune mechanisms of the gut that participate in responses to these pathogens is limited. Response: We evaluated non-antibiotic alternatives for intestinal disease resistance in commercial broiler chickens and their effect on intestinal tissue integrity and immune response. Results:Dietary administration of a natural plant product, capsaicin, increased resistance to Salmonella in broiler chickens, with no negative impact on live performance. Other experiments provided evidence of mast cells responding to coccidia in broiler chickens, which aids in characterizing the complex intestinal response to this disease. Live performance and intestinal responses showed a live vaccine was effective at inducing intestinal immunity to coccidia, and that genetic selection could also play a role in the response of broilers to this disease. This research contributes to understanding the host-pathogen interaction and role of mucosal immunity that could help in development of vaccines and genetic selection to control coccidiosis. This research has also provided evidence for potential alternatives to the use of antibiotics in feeding programs in chickens, which furthermore addresses needs of niche market poultry producers as well as increasing public concern with antibiotic resistant microorganisms and impending removal of antibiotics from food animal production.

PUBLICATION INFORMATION: 2001-07-01 TO 2006-06-30
Barri, A., K. Ameiss, J. El-Attrache, A. McElroy, and D.J. Caldwell, 2005. Effects of cytosine-phosphate-guanosine oligodeoxynucleotides (CpG-ODN) on Salmonella vaccination or BSA immunization of neonatal chickens. Poultry Sci. 84: Supp. 1.

PROJECT CONTACT INFORMATION
NAME: McElroy, A. P.
PHONE: 540-231-8750
FAX: 540-231-3010