EFFECTS OF DIETARY CHLORIDE AND MAGNESIUM ON THE INCIDENCE OF TIBIAL DYSCHONDROPLASIA IN CHICKENS FED ON CHINESE PRACTICAL DIETS

1. The effects of varying the concentrations of dietary magnesium and chloride on the performance, incidence of tibial dyschondroplasia and tissue element contents of broilers fed on Chinese practical maize soyabean meal diets was assessed. 2. Two concentrations of dietary chloride (1.5 and 3.5 g/kg) and 3 of dietary magnesium (2.0, 4.0 and 6.0 g/kg) were used to form 6 dietary treatments for a 21-d experimental period. 3. Results from this study indicated that the dietary ingredients of maize and soyabean meals produced in the northeast of China may predispose or influence the susceptibility of chickens to tibial dyschondroplasia. 4. High dietary chloride induces a high incidence of tibial dyschondroplasia (P<0.05) which could be ameliorated by dietary magnesium supplementation. 5. Dietary magnesium plays an anti-rachitic role by improving the deposition of copper and zinc in the bone tissue. 6. Supplementation with magnesium to 4.0 g/kg is recommended for broiler diets in northeast China.