Impairment of phagocytosis in chicken monocytes during aflatoxicosis.

Graded doses of dietary aflatoxin (0, .625, 1.25, 2.5, 5.0, and 10.0 microgram/g) were tested for their effect on the phagocytic and locomotive capacities of monocytes from chicken blood. The percentage and mean phagocytic activites were decreased significantly (P less than .05) at 2.5 microgram/g and above and at 1.25 microgram/g and above, respectively. Both the directed and undirected locomotion of monocytes were impaired significantly (P less than .05) at 2.5 microgram/g and above. A serum factor with the heat sensitivity of complement and which was required for optimal phagocytosis by monocytes also was reduced in activity during aflatoxicosis. Thus, the circulating element of the mononuclear phagocyte series has reduced capacity to perform its role in host defense during aflatoxicosis.