DISCUSSION
It is well documented that dietary DFMs modulate various aspects of immunity in broiler chickens (Lee et al., 2010a,b,c). Also, we have recently reported that the
exposure of growing chickens to used poultry litter stimulated humoral and cell-mediated immune responses, presumably due to contact with contaminating enteric pathogens (Lee et al., 2011). Given that dietary DFM or the type of litter influences host immunity, their interaction on developing post-hatch immunity is expected. However, to our knowledge, those expectations have never been answered. Thus, the present study was conducted to investigate whether dietary DFMs modulate immune response, with respect to humoral antibody response to Clostriium and Eimeria, and cell-mediated immunity as measured by cytokine production in broiler chickens raised on fresh, used or GD litter.