Submitted to: Poultry Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2000
Publication Date: N/A
Technical Abstract: To determine an optimal dose for coccidial inoculation and to evaluate genetic resistance or susceptibility in individual chickens, broilers were inoculated with four different doses of Eimeria maxima oocysts. Body weight gain, fecal oocyst shedding, plasma NO2- + NO3-, carotenoid, and interferon-gamma concentrations were measured at two different time periods spost-infection. The results showed significant dose and sex effects on most parameters and interaction between dose and sex in some parameters. The dose effects were mostly linear on the parameters, and quadratic fashions were also observed on some measurements. The measurements from chickens inoculated with 104 of oocysts displayed the highest correlation coefficients among oocyst shedding, body weight gain, carotenoid, and NO2- + NO3- concentrations. An infection index, calculated from the correlated parameters, displayed high correlation coefficients with the parameters. The infection index may be a better parameter for evaluating individual genetic resistance against coccidial infection.