Ultrastructure of Fusarium-induced tibial dyschondroplasia in chickens: a sequential study.

Female broiler chicks were randomly placed into two groups; one was treated twice daily with TDP-1 (a mycotoxin produced by Fusarium roseum), the other was controls. Chicks were sacrificed after 2, 4, 6, 8, 10, and 14 days of treatment and were evaluated for tibial dyschondroplasia. TDP-1-treated chicks examined after 2, 4, or 6 days of treatment had either no gross lesions (2 days) or mild gross lesions (4 and 6 days); growth plates from these groups did not have ultrastructural changes. TDP-1-treated chicks examined after 8, 10, or 12 days of treatment had moderate to severe gross lesions of tibial dyschondroplasia. These groups also had intracellular lipid accumulation and necrosis of chondrocytes within the retained cartilage. It was concluded that the cellular changes in tibial dyschondroplasia develop only after the cartilage accumulates; the changes are sequelae, possibly due to nutrient depletion from an increased distance between chondrocytes and perforating epiphyseal vessels, their nutrient source.