Influence of excess dietary copper on lipid composition of calf tissues

Lipid composition of calf liver, heart, and skeletal muscle was measured, as affected by control Cu (10 ppm in DM), high Cu (1000 ppm), or high Cu plus high Zn (1000 ppm) in milk replacer. High dietary Cu increased all lipid classes in liver, some in the heart, and decreased all lipid classes except cholesterol in muscle. Zinc inhibited many of the changes in tissue lipid classes by excess copper. High Cu intake increased fatty acid unsaturation (palmitoleic, oleic, linoleic acids) and decreased stearic acid in phosphatidylcholine and phosphatidylethanolamine of liver and heart. Excess Cu tended to have an opposite effect in changing fatty acid concentrations in liver and muscle. Activities of various desaturases and elongases were estimated in liver, heart, and muscle using ratios of fatty acid precursors to products in combined phosphatidylcholine and phosphatidylethanolamine. High Cu intake frequently altered activities of these enzymes in all three tissues with additional high Zn usually coregulating activity in the direction opposite to Cu.