Tibial dyschondroplasia in growing chickens experimentally intoxicated with tetramethylthiuram disulfide.

Graded levels of tetramethylthiuram disulfide (0, 30, 60, 120, and 240 ppm) were incorporated into a broiler starter ration fed to chickens from one day old to 8 weeks of age. Clinical signs of leg abnormalities were observed as early as 5 days after the beginning of the trial. After the 3rd week, the joints were shown to present lesions, especially in the femorotibial articulation, comparable to the ones found in perosis. Tibiotarsus and other organs from the birds were examined for pathological changes at weekly intervals. Histologically, the tibiotarsus has shown an osteochondrodystrophy identical to that of tibial dyschondroplasia (TD), although it varied according to the level of tetramethylthiuram disulfide. The histopathology of the thyroid gland of the chickens involved in the present experiment will be reported in a separate manuscript.