KINETICS OF SERUM ANTIBODY-RESPONSES IN BROILER CHICKS AGAINST CRYPTOSPORIDIUM-BAILEYI

The kinetics of serum antibody responses in broiler chickens against C ryptosporidium baileyi were studied. Broilers were inoculated intratra cheally with 250,000 C. baileyi oocysts at 1, 7, or 14 days of age. An tibody was quantified by an enzyme linked immunosorbent assay. Anti-cr yptosporidial serum immunoglobulins (IgM and IgG) were detected 9 days post-inoculation (DPI) in birds inoculated at 1 or 7 days of age with oocysts and 4 DPI when 14-day-old birds were inoculated. Results also reaffirmed age related susceptibility, with day-old birds being more susceptible than 7-day, and 14-day-old birds were not susceptible to c linical disease. The susceptibility to infection correlated with the a mount and duration of the IgM response. Day-old inoculated birds devel oped a higher, longer-lasting response than 7 or 14-day-old infected b irds.