A US Department of Agriculture (USDA) research found that poultry which were fed hyperimmune egg yolk antibodies had better immunity against intestinal diseases
The antibiotic-free technology involves extracting antibodies from egg yolks from pathogen-free hens or female chickens that have been hyperimmunised - injected with a vaccine that contains inactivated pathogenic organisms. Hyperimmunised birds have a greater-than-normal immunity and produce a large amount of antibodies.
Avian immunologist Hyun Lillehoj at the Agricultural Research Service (ARS) Animal Parasitic Diseases Laboratory in Beltsville, partnered with collaborators from the Mexican company IASA (Investigacíon Aplicada, South Africa) on the studies. ARS is USDA's chief intramural scientific research agency, and this research supports the USDA priority of promoting international food security.
The group demonstrated the effectiveness of inducing passive immunity in young birds, which have no immune protection right after hatching, against coccidiosis, a devastating poultry disease.
Birds affected by coccidiosis are unable to absorb feed or gain weight. The disease costs the poultry industry about US$3 billion worldwide each year.
Treatments used to reduce the spread of disease include good management practices and live vaccinations. However, antibiotic-free alternatives are important to help fight drug-resistant strains and for organic poultry farmers, according to Lillehoj.
In the study, one-day-old chickens were given feed mixed with spray-dried egg yolk powder prepared from hens hyperimmunised with multiple species of the parasite Eimeria, which causes coccidiosis. The chickens were then exposed to live coccidia parasites. Chickens that had received the hyperimmune egg yolk antibodies gained more weight and shed significantly fewer Eimeria in their feces. The treated birds also had less gut lesions than chickens that did not receive the treatment.