Four commercial chicken broiler breeds were compared after 7 days of foodrestriction for the competence of mononuclear phagocytic system cells. Peritoneal exudate cells collected from food-restricted birds after single intraperitoneal injection of 3% Sephadex G-50 were assayed for incidence, phagocytic activity against opsonised and unopsonised sheep red blood celts (SRBC) and bactericidal potential against opsonised Escherichia coli. Macrophages from food-restricted birds exhibited reduced phagocytic activity against opsonised and unopsonised SRBC and diminished bactericidal potential against opsonised E. coli com pared with controls. The results of the present study suggest that food-restriction adversely affects the immune response and makes the birds susceptible to different pathogens.
