A novel approach to coccidiosis contro

摘要

CoxAbic is a new concept in coccidiosis control. The concept is based on vaccinating breeders with a sub-unit vaccine produced from a protein extracted from the gametocyte stage of E. maxima. The sub-unit protein complex is called APGA (Affinity Purified Gametocyte Antigens) and is composed of an 82 kDa protein and a 56 kDa protein. Vaccination with APGA induces production of antibodies that specifically react with the Wall Forming Bodies (WFBs) in the gametes. The WFBs eventually form the hard protective wall of the oocyst. The specific APGA proteins appear to be well conserved among the common broiler chicken species of Eimeria (E. acervulina, tenella and maxima). The breeder birds are vaccinated twice with CoxAbic, four weeks apart. The vaccine hyperimmunises the breeders, producing specific antibodies that are passed to their broiler chicks through the egg yolk. These antibodies are thought to interfere with the wall formation of the oocysts. This specific maternal immunity protects the chicksduring the initial exposure to coccidia in the litter, permitting the development of active immunity against the species of Eimeria found in the litter. The level of immunity can be measured in the vaccinated breeders and in the broiler offspring by using a specific ELISA test. In this manner the results of vaccination can be verified. In large production systems where the vaccine is currently being used, performance of broiler chicks in the field is better than those grown with the use of coccidiostats or live vaccines. In addition, improved quality of life of the vaccinated breeders has been repeatedly observed when compared to non-vaccinated controls. Egg production is also increased in vaccinated breeders.