Submitted to: Advances In Medical and Veterinary Vitology Immunology and Epidemiology
Publication Type: Book / Chapter
Publication Acceptance Date: July 1, 2002
Publication Date: N/A
Interpretive Summary: Coccidiosis, an intestinal infection caused by intracellular protozoan parasites belonging to several different species of Eimeria, costs the poultry industry more than $600 million in annual losses. Infection with coccidia parasites seriously impairs the growth and feed utilization of livestock and poultry. In this review article, ARS scientists review current knowledge on avian immunity and host immunobiology of avian coccidiosis in chickens. This information will provide rational background information that is useful for the development of novel control strategy against coccidiosis. Current control method using drugs will need to be replaced by non-drug-dependent method due to an increasing drug resistance of coccidia and increasing consumer's concern on the presence of drug residues in food supply. Therefore, alternative control strategy against coccidiosis needs to be developed. In this paper, ARS scientists, in collaboration with scientists at University of Maryland, investigated the effect of probiotic dietary supplement on host immune response against coccidiosis. Results show for the first time that probiotics enhanced local cell-mediated immunity and increased host resistance against coccidiosis in chickens. These results provide optimism that increased basic knowledge on the interaction of nutrition and host immune system will generate novel control strategy against coccidiosis.
Major protozoa which afflict chickens include 7 or 8 spp. of poultry coccidia (genus Eimeria causing avian coccidiosis. Demands for more efficient poultry production and intensive poultry-rearing practices have led to the heightened risks of disease transmission and major economic losses due to infectious diseases. Avian coccidiosis, the major parasitic disease of poultry, causes more than $600 million in losses in prophylacti medication and this number is expected to rise due to the cost involved in developing new drugs. Economic losses due to coccidiosis include mortality, malabsorption, inefficient feed utilization and impaired growth rate in broilers, and a temporary reduction of egg production in the layers. Although chemotherapy has been extensively used to control coccidiosis, the increasing incidence of drug resistant coccidia and the escalating public anxiety over the chemical residues in the meat and eggs mandates the development of alternative methods to control coccidiosis.