33 

 only in erythrocytes, skin, and cornea. Metallothionien 

 levels were determined in liver, pancreas and kidney. There 

 were no treatment differences (P > .05) in serum or 

 erythrocyte Zn content for all days of collection. Serum Cu 

 concentrations tended to decrease with all treatments. There 

 were no treatment differences (P > .05) in Zn and Cu tissue 

 concentrations and liver, kidney and pancreas MT 

 concentrations. Tissue Cu concentrations did not drop in the 

 supplemented treatments when compared to controls. At 

 adequate levels of dietary Zn, bioavailability of supplemental 

 Zn sources may be less important than under conditions of 

 limited dietary Zn or if very high levels of supplemental Zn 

 are fed. 



