Histological study of tibial dyschondroplasia-like lesion from light-type chicks fed cysteine-supplemented diets.

Tibial dyschondroplasia (TD)-like lesions were induced in New Hampshire x Single-Comb White Leghorn cross chicks (NH x SCWL) by feeding excess levels of cysteine. The chicks fed a corn/soybean-meal-based diet had no spontaneous TD. The chicks fed the basal diet supplemented with 1.5% or 3.0% cysteine showed more than 50% TD-like lesions at 10 days of age; in another experiment, 1.6% cysteine induced TD (15%) at 3 weeks of age. A low incidence of rachitic-like lesions was found in Expt. 2 but was not associated with the dietary treatments. The TD-like lesion had a normal upper growth plate and a large mass of cartilage extending into the metaphysis; in contrast, the rachitic-like lesion had a widened upper growth plate. Microscopic examinations of the growth plates showed a widened prehypertrophic zone for the TD-like lesion and a widened proliferative zone for the rachitic-like lesion compared with the normal growth plate.