Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/1996
Publication Date: N/A
Citation: Interpretive Summary: The control of avian coccidiosis, an intestinal disease of chickens that produces losses of over $300 annually, is essential for the continued growth of the U.S. poultry industry. Coccidial control is mainly through use of drug medication in the feed. Increased drug resistance by the coccidial has caused great concern in the poultry industry, because if this tend is not reversed, such resistance could reach catastrophic proportions within the next 3 years. Therefore it is essential that new avenues for control be investigated. Use of live vaccines for immunization against coccidiosis have been available for over 40 years, but have not been used in broiler chicken flocks because of lack of an efficient delivery system, and poorer performance by the birds in the important economic parameters of weight gain and feed utilization. In the present study it was found that use of a gel delivery system gave a more uniform vaccination of day old broiler chickens than other systems tested. In addition, this type of vaccination resulted in bird performance that was similar to that seen with birds on anticoccidial medication. Thus, this type of immunization may be a viable alternative to use of anticoccidial medication in the control of this parasite.
Technical Abstract: The use of a gel immunization technique with Immucox vaccination was compared and evaluated against other immunization methods in battery and floorpen immunization trials. Gel immunization was found to be superior to gavage, spray cabinet or the conventional delivery method of Immucox in a battery trial. Significantly enhanced protection as measured by weight gain, coupled with the establishment of a more uniform infection, as evidenced by greater intestinal lesions and increased oocyst shedding, was seen with the gel immunized birds. Crossprotective battery trials determined that the strain of Eimeria maxima found in the Immucox vaccine failed to elicit protection against a recent field isolate of E. maxima as measure by average weight gain and lesion scores. A reformulation of the Immucox vaccine was required to elicit a protective immune response against challenge by the field strain. A floorpen experiment demonstrated that gel immunization of day old roaster chickens resulted in performance parameters of average weight gain, average bird weight and feed conversion that did not differ from medicated nonimmunized birds.