Effect of feeding different levels of zinc and vitamin A on morphometry and mineralization of tibia bone in broiler chickens

An experiment was conducted to investigate the impact of Zinc & Vitamin A on skeletal development in broiler chickens. A total of 96 tibia bone (8 per treatment) collected at the end of 42-d feeding trial involving three levels of zinc (40, 60 and 80 mg/kg) and each with four levels of supplemental vitamin A (1500, 3000, 6000 and 10, 000 IU/kg) in a 3×4 factorial experiment were used for measurement of bone morphometry and mineralization traits in broiler chickens. Results indicated that Significantly (P<0.01) lower tibia proximal width was observed at a dietary combinations of 60 mg Zn with 3000 IU/kg vitamin A followed by 40 mg Zn with 10, 000 IU/kg vitamin A and 60 mg Zn with 1500 IU/kg vitamin A than those observed in other dietary combinations. Mid shaft width of tibia was significantly higher at a dietary combination of 80 mg Zn with 10, 000 IU/kg vitamin A than those observed in other dietary combinations of Zn and vitamin A levels. Bone length and distal width did not differ significantly due to different dietary treatment. Significantly (P<0.05) higher percent bone ash was observed in a dietary combination of 60 mg Zn with 3000 IU/kg vitamin A followed by 80 mg Zn with 3000 IU/kg vitamin A than those observed in other dietary combinations. Bone weight, bone ash, bone calcium and bone Zn differed significantly due to different dietary Zn levels. Significantly (P<0.05) higher bone weight, bone ash, bone calcium and bone zinc were observed at higher level of zinc (80mg/kg diet) than its lower levels in the diet. Significantly (P<0.05) higher bone ash and calcium were observed at 3000 IU/kg vitamin A than those recorded at other levels in the diet. Based on the results it was concluded that a dietary combination of 80 mg Zn/kg diet with 3000IU/kg vitamin A was found adequate for optimum morphometry and mineralization of bones in broiler chickens.