Tibial dyschondroplasia (TDP) is a common and economically important bone deformation in growing broiler chickens and turkeys. The lesion appears in a cone of cartilage extending distally from the proximal tibiotarsalphysis.
The most likely cause of this deformation is a toxin called fusarochromanone produced by Fusarium equiseti. When added to the diet of broiler chicks at 75 ppm, 100 percent of the chicks showed symptoms of TDP. This toxin may be largely responsible for the TDP syndrome in poultry; it also kills chick embryos in fertilized eggs.