Influence of dietary tetramethylthiuram disulfide (a fungicide) on growth and incidence of tibial dyschondroplasia in single comb White Leghorn chicks.

The effect of dietary tetramethylthiuram disulfide (TMTD) (0, 30, or 60 mg/kg diet) on the performance and incidence and severity of tibial dyschondroplasia (TD) in Single Comb White Leghorn (SCWL) chicks was studied in a 6-week experiment. Body weights (3 weeks of age) and bone ash (4 and 6 weeks of age) of chicks fed either 30 or 60 mg TMTD/kg diet were significantly lower compared to controls. Dietary TMTD, however, significantly increased the incidence and severity of TD in layer chicks with the highest incidence (69%) occurring in 6-week old-birds. This study showed that SCWL chicks were susceptible to TMTD-induced TD as early as 2-weeks of age and that the condition persisted throughout the growing phase.

Tibial dyschondroplasia in single-comb White Leghorn chicks fed tetramethylthiuram disulfide (a fungicide).

Supplementing a practical chick starter diet with 30 mg tetramethylthiuram disulfide per kg of diet produced tibial dyschondroplasia (TD) in single-comb white leghorn chicks without compromising growth or bone mineralization. The incidence and severity of the lesion increased over time, with the highest incidence (40%) occurring in 4-week-old chickens. Microscopically, the lesion was consistent with the description of TD in broilers. This is the first known report of TD in the layer-type chick, which heretofore was felt to be highly resistant to TD.