Decreased immune response and increased incidence of tibial dyschondroplasia caused by fusaria grown on sterile corn.

Corn, feed, and litter samples reported to be associated with feed refusal, diarrhea, leg weakness, and mortality were evaluated for the presence of toxic substances. Intubated residues of ethyl acetate extracts of these samples did not cause gross lesions, diarrhea, or mortality in young New Hampshire x Single Comb White Leghorn crossbred chicks. Fusarium moniliforme was the predominant fungal species found in unpelleted feed and corn samples. Young broiler chicks, fed diets supplemented with 2 or 8% corn cultures of selected F. moniliforme isolates from a suspected toxic corn sample, failed to develop clinical signs of mycotoxicosis. However, some isolates resulted in decreased antibody responses to SRBC. Corn cultures of some Fusarium equiseti and Fusarium semitectum strains also decreased the immune response. Cultures of three F. equiseti strains from barley and potato induced tibial dyschondroplastic lesions in young broiler chicks. Other F. equiseti strains and strains of other Fusarium species did not cause this skeletal abnormality.