The current dietary copper(Cu)requirement(8 mg/kg)of broilers is mainly based on growth,hemo-globin concentration,or hematocrit,which might not be the most sensitive indices to evaluate dietary Cu requirements of broilers.The present study was carried out to estimate dietary Cu requirements of broilers fed a conventional corn-soybean meal diet from 1 to 21 d of age using biochemical or molecular biomarkers.A total of 384 one-day-old Arbor Acres male broilers were randomly allocated to 1 of 6 treatments with 8 replicates and fed a Cu-unsupplemented corn-soybean meal basal diet containing 5.17 mg Cu/kg by analysis and the basal diet supplemented with 3,6,9,12 or 15 mg Cu/kg as CuSO4·5H2O for 21 d.Regression analysis was performed to estimate the optimal dietary Cu level using the broken-line model.Dietary supplemental Cu level affected(P＜0.05)Cu contents in serum and liver and kidney monoamine oxidase(MAO)activity,but had no effects(P＞0.05)on the growth performance,Cu con-tents in heart,kidney,pancreas and spleen,Cu-and zinc-containing superoxide dismutase(CuZnSOD)activity and ceruloplasmin content in serum,CuZnSOD and cytochrome c oxidase(COX)activities and ceruloplasmin,CuZnSOD,MAO A,MAO B,COX 4I1 and COX 1 mRNA and protein expressions in the above tissues of broilers.As dietary supplemental Cu levels increased,Cu contents in serum and liver increased linearly(P＜0.05),but kidney MAO activity decreased linearly and quadratically(P＜0.05).The estimated dietary Cu requirement based on the fitted broken-line model(P=0.035)of kidney MAO activity was 11.30 mg/kg.In conclusion,kidney MAO activity is a new and sensitive criterion to evaluate the dietary Cu requirement of broilers,and the dietary Cu requirement was 11.30 mg/kg for broilers fed the con-ventional corn-soybean meal diet from 1 to 21 d of age,which is higher than the current National Research Council(NRC)Cu requirement(8 mg/kg)of broilers.

Yun Hu;Zhiyong Chen;Lin Lu;Liyang Zhang;Tao Liu;Xugang Luo;Xiudong Liao

Poultry Mineral Nutrition Laboratory,College of Animal Science and Technology,Yangzhou University,Yangzhou,225000,China;Mineral Nutrition Research Division,State Key Laboratory of Animal Nutrition,Institute of Animal Science,Chinese Academy of Agricultural Sciences,Beijing,100193,China;Biochemistry Department,Case Western Reserve University,Cleveland,44106,USA

动物营养（英文）

[1]Yun Hu;Zhiyong Chen;Lin Lu;Liyang Zhang;Tao Liu;Xugang Luo;Xiudong Liao-.Determination of dietary copper requirement by the monoamine oxidase activity in kidney of broilers from 1 to 21 d of age)[J].动物营养（英文）,2022(01):227-234

unsupplemented,CuZnSOD,4I1

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