Abstract of Dissertation Presented to the Graduate School 



of the University of Florida in Partial Fulfillment of the 



Requirements for the Degree of Doctor of Philosophy 



RELATIVE BIOAVAILABILITY OF DIFFERENT ORGANIC AND INORGANIC 

 ZINC AND COPPER SOURCES IN RUMINANTS AND RATS 



By 



LUIS X. ROJAS 

 April 1994 



Chairperson: Dr. L. R. McDowell 

 Major Department: Animal Science 



Four experiments (EXP) were conducted to compare the 



bioavailability (BAV) of amino acid complexed (Zn lysine, 



ZnLys ; Cu lysine, CuLys; Zn methionine, ZnMet ) and inorganic 



sources of Zn and Cu by determining Zn, Cu and metallothionein 



(MT) concentrations of various fluids and tissues. In EXP 1, 

 cattle were given supplemental (SUP) ZnMet, ZnS0 4 , and ZnO 



(3 60 mg Zn/d) for 4 wks, withdrawn for 4 wks and resumed for 

 another 4 wks. No treatment (T) differences were determined 

 under those conditions for Zn and Cu in fluids and tissues, 

 and MT in tissues. In EXP 2, wethers were given SUP ZnMet, 

 ZnLys, ZnS0 4 , and ZnO (360 mg Zn/kg) for 3 wks, withdrawn for 

 4 wks and resumed for another wk . By d 49 serum Zn had 

 increased less for controls than most T, and by d 55 had 

 increased more for ZnLys than most T. The ZnLys T had the 

 highest Zn and MT in kidney, liver and pancreas. Both ZnS0 4 



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