Genetic Sensitivity to Pathogenesis: Response to E. maxima Challenge in High and Low Antibody Selection Lines of Chickens

Abstract Text: Pathogen exposure often causes a reduction in voluntary food intake or anorexia. The duration of anorexia depends on pathogen type and dose, and likely animal genotype. Chicks from two lines of White Leghorns, divergently selected for 37 generations for high (HAS) or low antibody response to sheep red blood cells, were challenged with two doses of E. maxima at 8 d post-hatch. We hypothesized that HAS chicks would express a greater magnitude of anorexia, but for shorter duration. At 6 d post-inoculation, jejunum lesions were moderate regardless of dose, and higher in HAS chicks. In both lines, weight gain and feed intake declined due to pathogenesis. Anorexia occurred later, and persisted less, in HAS chicks. Its magnitude was similar across lines, and dose independent. Our supposition of heightened immune-responsiveness to a pathogen from selection for high antibody titer appears doubtful.

Keywords:

chicken

antibody selection lines

genetic sensitivity

coccidiosis