The Study Of Supplementing Single, Or Multiple Trace Elements (Mn, Cu, Zn) In Laying Hens Diet

An experiment was conducted to evaluate effects of dietary content and combinations of Mn, Cu and Zn on performance, apparent nutrient availability, egg quality, trace element content in excreta and plasma parameter of laying hens. A total of 450 Lohmann Brown Hens, 275-day-old, were randomly allotted to 1 of 4 groups for 6 replicates of 15 birds each were fed on one of the following five diets: Group A,a commercial laying hens diet that was not supplemented with trace element;Group B,14 mg/kg Mn supplementation with manganese sulfate (MnSO4 - 14); Group C, MnSO4 - 34; Group D, MnSO4 - 54 + CuSO4 - 2 + ZnSO4 - 13.This study indicated that:1. The contents of Cu, Fe, Zn and Mn in the basal diet could meet layers'requirement, and that Mn had an obvious impact on laying hens'production performance and absorptive ability of other elements. The study also implied that the dietary contents of Mn and apparent available Mn for optimal production performance should not exceed 46 mg/kg and 14.1 mg/kg, respectively.2. A significant linear reduction in egg Zn content was found as the apparent available Mn was increased from 14 to 25.47 mg/kg. A significant increasing in egg Cu when the apparent available Cu was increased. The content of Mn, Cu, Zn and Fe in laying hens'excreta was significantly decreased in Group A.3. A significant linear increasing was found in egg yolk cholesterol when apparent available energy was increased. The cholesterol content in egg yolk and plasma (2 h after feeding) was linear enhanced as apparent available Mn increased.4. The E₂ and AST content in plasma (4 h after feeding) wans linear increased as apparent available Cu enhanced. A significant linear enhancing was found in plasma insulin (4 h after feeding) while apparent available Zn was increased.5. The production performance was relative enhanced as plasma E2, T4 (4 h after feeding) increased. Both the egg production and egg yield were increased when plasma ALP was enhanced. There were no significantly differ of plasma ALP, egg yield, egg production and egg...