45 

 complex with MT than the Cu present in any of the other 

 treatments. In a similar manner, because of its relatively 

 higher MT values, the liver, kidney and pancreas Cu in the 

 ZnMet and ZnS0 4 treatments is bound to MT in comparison with 

 ZnO and the negative control. Despite the higher MT levels in 

 these tissues, this protein accounts for only a small portion 

 of the Cu and Zn concentration in these tissues. The 

 unexplainable factor is that the serum Cu levels were similar 

 for all treatments and controls should have had higher serum 

 Cu concentrations. This is expected since serum Cu 

 (ceruloplasmin) is a hormonally regulated process. The only 

 consolation is that levels for the control treatment were 

 increasing (but not different) by the end of the experiment. 

 Very few studies have evaluated the actual biological 

 value of different organic Zn sources. Results of this study 

 indicate that the organic Zn sources can be more (ZnLys) or 

 equally (ZnMet) available as the best inorganic Zn source. 

 There were no differences in the particular target pools (or 

 tissues other than liver, kidney and pancreas) for the Zn 

 sources, suggesting that Zn from the different sources may be 

 metabolized equally in those tissues. Zinc from the ZnLys 

 supplementation may be metabolized differently than that of 

 the other sources because of its higher levels in the liver, 

 kidney and pancreas . 



