Effects of Different Dietary Copper and Vitamin A Levels and Their Interaction on Growth Performance and Blood Physico-parameters in Broilers

A4×2(Cu×VA) factorial arrangement with replicates was designed to investigate the effects of different dietary copper (0,8, 150, 225 mg/kg diet) and vitamin A levels (1 500, 5 000 mg/kg diet) and their interaction on growth performance, hemoglobin (Hb) concentration, red cell count (RCC), packed cell volume (PCV), erythrocyte sedimentation rate (ESR) and white cell count (WCC) in broilers. Broilers were randomly allotted to eight groups with four replicated in each group and fourteen broilers in each replicate. Results showed dietary higher copper levels (150 and 225 mg/kg) decreased significantly body weight gain, feed intake, Hb concentration and ESR from 0 to 4 weeks, and improved WCC significantly in the whole period (P<0. 05). When dietary copper supplemental level was 0 mg/kg, Hb concentration in the whole period, PCV from 5 to 7 weeks and ESR from 0 to 4 weeks improved significantly (P<0. 05), but different dietary copper levels did not significantly affect RCC in the whole period (P>0. 05). When vitamin A was 5 000 IU/kg, better growth performance, Hb concentration and RCC in the whole period were gained, and PCV and WCC from 0 to 4 weeks increased significantly (P<0. 05), but 5 000 IU/kg vitamin A significantly decreased PCV from 5 to 7 weeks (P<0. 05). CuVA interaction significantly affected body weight gain from 0 to 4 weeks and feed/gain in the whole period (P<0. 05), and significantly affected Hb concentration, ESR and WCC in the whole period (P<0. 01), PCV from 5 to 7 weeks (P<0. 01), and they had complementary effect, both Cu (8 mg/kg) ×VA (5 000 IU/kg) and Cu (0 mg/kg)×VA (5 000 IU/kg) had better growth performance, RCC, Hb concentration, PCV and ESR from 0 to 4 weeks. Cu-VA interaction didn't significantly affected RCC in the whole period (P>0. 05). When copper level in basal diets was 16-23 mg/kg, dietary appropriate copper supplemental level was 8 mg/kg from 0 to 4 weeks, and 0-8 mg/kg from 5 to 7 weeks. Appropriate vitamin A supplemental level was 5 000 IU/kg in the whole period.