18 

 Other suggested storage proteins in liver include superoxide 

 dismutase, MT, and mitochondrocuprein (Bremmer , 1980) . 



Bioavailability of Sources 



Supplementation of Cu as CuS0 4 , CuC0 3/ CuCl 2 or Cu(N0 3 ) 2 

 resulted in similar elevations in blood and plasma Cu 

 concentrations in sheep (Lassiter and Bell, 1960) and cattle 

 (Chapman and Bell, 1963), but both Cu : and CuO forms were 

 less available (Lassiter and Bell, 1960) . In the growing 

 chick, Cu from Cul and Cu 2 were 82 and 76%, respectively, as 

 available as CuS0 4 (McNaughton et al . , 1974) . According to Ho 

 et al . (1980) , amino acid complexes or organically bound forms 

 apparently have a higher bioavailability than inorganic Cu 

 sources because of their ability to prevent the occurrence of 

 hypocupremia in beef cattle. 



Other recent studies with swine (Cromwell et al . , 1989), 

 chicks (Baker et al . , 1991), sheep (Pott et al . , 1992) and 

 cattle (Clark et al . , 1993) show that CuS0 4 is more available 

 than CuO. Baker et al . (1991), however, suggested similar 

 bioavailability for Cu from a Cu lysine (CuLys) complex to 

 that of CuS0 4 in chicks. Liver Cu has been reported to 

 increase more rapidly when cattle were supplemented a Cu 

 proteinate versus CuS0 4 (Clark et al . , 1993) . In studies with 

 weanling pigs (Coffey et al . , 1992; Coffey et al., 1993), it 

 was suggested that CuLys and CuS0 4 were not only similar for 

 many aspects of bioavailability but that CuLys was also an 



