Interaction of Dietary Zinc and Vitamin A Influences the Zinc Deposition and some Enzymes` Activity in Broilers

Abstract

576 broilers are experimented on with 6 × 2 (Zn × vitamin A) repetitive experiment in attempt to study the influence of different dietary zinc levels (40,80 ,120 ,160 ,200 and 320 mg/ kg) and dietary vitamin A levels (2700 and 8800 IU/ kg) on vitamin A metabolism, zinc concentration in liver and tibia, zinc apparent deposition rate, serum ALK activity, CuZn-SOD activity in liver and serum, and serum insulin concentration. Results showed that vitamin A concentration in serum increased with the increasing of zinc level in the diet, and that in livers decreased accordingly, which means that zinc can mobilize vitamin A of liver into serum. When dietary zinc level was 320 mg/kg, vitamin A concentration in serum, liver and kidney increased at the same time, perhaps higher dietary zinc level promoted vitamin A absorption except for mobilizing it into serum. Higher dietary vitamin A level (8800 IU/kg) increased zinc concentration in liver and tibia slightly. Zinc apparent deposition rate increased with the increasing of dietary zinc level within certain range and then decreased.；dietary Zinc level has a prominent influence on CuZn – SOD in serum when P < 0. 01; and the result also shows that dietary zinc level, vitamin A level and their interaction has a respectively prominent influence on ALK, serum insulin concentration is also apparently affected.