Immunosuppressive effects of Fusarium moniliforme corn cultures in chickens.

In the present study, the toxic and immunosuppressive effects of three isolates of Fusarium moniliforme (MRC 826, MRC 1069, and RRC 408) in male White Leghorn chickens were investigated. Chickens were fed diets containing .5, 5.0, or 25% of F. moniliforme corn cultures for 6 wk. About 30% of the chickens fed RRC 408 had leg weakness. Relative weights of bursae of Fabricius were lower in birds fed all doses of MRC 826. Birds fed 5.0 or 25% MRC 1069 had lower relative spleen weights. Thymus weights were lower in birds fed .5 and 5.0% RRC 408, but not in those fed 25%. Immunosuppressive effects were determined by measuring serum levels of primary and secondary agglutinin responses to SRBC and Brucella abortus. Birds fed 5.0 or 25% MRC 826 were immunosuppressed, as shown by low antibody titers to B. abortus in both the primary and secondary responses. Isolate MRC 1069 caused a decrease in secondary response to SRBC at 25% and B. abortus at the 5.0 and 25% of culture material. The RRC 408 isolated reduced the secondary response to SRBC at all doses and response to B. abortus at 5.0 and 25% of culture material. These results appear to be the first report that feed contaminated with F. moniliforme can produce deficiencies in the immune system of chickens.