MOLYBDENUM BUT NOT COPPER COUNTERACTS CYSTEINE-INDUCED TIBIAL DYSCHONDROPLASIA IN BROILER CHICKS

Studies were conducted to evaluate the ability of copper and molybdenum to prevent cysteine-induced tibial dyschondroplasia in broiler chicks. Experiment 1 was a 3 x 3 factorial arrangement of treatments used to investigate the interaction between Cu (0, 150 or 300 mg/kg diet) and Mo (0, 10, or 100 mg/kg diet) on cysteine-induced tibial dyschondroplasia. Molybdenum at both supplemental levels, but not Cu, prevented cysteine-induced tibial dyschondroplasia. In Experiment 2 (a 3 x 3 factorial arrangement of treatments with 0, 5 or 10 g/kg diet of cysteine and 0, 10 or 100 mg/kg diet of Mo), Mo prevented cysteine-induced but not spontaneous tibial dyschondroplasia. Cysteine and Mo did not affect the mechanical properties of the tibiotarsus. In Experiment 3, cysteine (0 or 10 g/kg diet) and Mo (0 or 100 mg/kg diet) were used to study the tissue concentrations of mineral and hepatic sulfite oxidase activity. Supplemental Mo increased Mo concentrations in the plasma and liver. Cysteine prevented these increases; however, cysteine, in the absence of supplemental Mo, did not affect concentrations of Mo in these tissues. Dietary cysteine and/or Mo did not affect tissue levels of Cu. We conclude that Mo prevents cysteine-induced tibial dyschondroplasia and that the induction of tibial dyschondroplasia by cysteine is not related to the Mo and Cu deficiency.