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==1. What is Copper?==

==What is Copper?==

Copper belongs to the group of nutrients called the trace elements. These are essential minerals but are designated this particular description as they are required in much smaller amounts than major minerals such as calcium and phosphorus. Copper can occur in very small amounts in the free state but most copper exists as cuprous or cupric salts, with oxidation states of Cu1+ and Cu2+ respectively.

Copper belongs to the group of nutrients called the trace elements. These are essential minerals but are designated this particular description as they are required in much smaller amounts than major minerals such as calcium and phosphorus. Copper can occur in very small amounts in the free state but most copper exists as cuprous or cupric salts, with oxidation states of Cu1+ and Cu2+ respectively.

==2. Why is it Important?==

==Why is it Important?==

Copper has many physiological functions. It is an essential component of a number of enzymes that catalyse oxidation reactions. It is also involved in iron metabolism, energy metabolism and the formation of normal hair colour.

Copper has many physiological functions. It is an essential component of a number of enzymes that catalyse oxidation reactions. It is also involved in iron metabolism, energy metabolism and the formation of normal hair colour.

==3. Roles in the Body==

==Roles in the Body==

Each of the enzymes that requires copper can be linked to a key metabolic process and this in turn defines the essentiality of copper as a nutrient. For example, lysyl oxidase is involved in connective tissue formation while ferroxidase enzymes are involved in iron metabolism and the formation and development of red blood cells. Copper is a component of the enzyme superoxide dismutase, which is involved in protecting the body against oxidative damage. As a component of tyrosinase it is essential for the formation of the pigment melanin and therefore for normal hair colour.

Each of the enzymes that requires copper can be linked to a key metabolic process and this in turn defines the essentiality of copper as a nutrient. For example, lysyl oxidase is involved in connective tissue formation while ferroxidase enzymes are involved in iron metabolism and the formation and development of red blood cells. Copper is a component of the enzyme superoxide dismutase, which is involved in protecting the body against oxidative damage. As a component of tyrosinase it is essential for the formation of the pigment melanin and therefore for normal hair colour.

Copper is absorbed primarily from the small intestine; absorption is influenced by the dietary copper content, being increased when the copper intake is low. In the liver copper is bound to ceruloplasmin, which becomes the principal form of copper transported in the plasma. Iron and zinc decrease the availability of copper; zinc is a particularly potent inhibitor of copper absorption. This occurs by zinc stimulating the formation of metallothionein, a protein that has a high affinity for binding copper. Copper balance occurs mainly via biliary excretion <span style="color:red">[WikiVet Link to section 5]</span>.

Copper is absorbed primarily from the small intestine; absorption is influenced by the dietary copper content, being increased when the copper intake is low. In the liver copper is bound to ceruloplasmin, which becomes the principal form of copper transported in the plasma. Iron and zinc decrease the availability of copper; zinc is a particularly potent inhibitor of copper absorption. This occurs by zinc stimulating the formation of metallothionein, a protein that has a high affinity for binding copper. Copper balance occurs mainly via biliary excretion <span style="color:red">[WikiVet Link to section 5]</span>.

==4. Consequences of Copper Deficiency==

==Consequences of Copper Deficiency==

===Dog:===  

===Dog:===  

#'''Effects on reproduction''': In adult female cats fed low dietary copper levels (3 or 6 mg/kg DM as cupric sulphate) had an effect on reproductive efficiency, increasing the time for successful conception compared with control cats fed copper at 10 mg/kg diet. However pregnancy rates were unaffected<ref name="Fascetti">Fascetti, AJ, Morris, JG, Rogers, QR (1998). “Dietary copper influences reproductive efficiency of queens”. J Nutr. 128:2590S-2592S.</ref><ref>Fascetti, AJ, Rogers, QR, Morris, JG (2000). “Dietary copper influences reproduction in cats”. J Nutr. 130:1287-1290.</ref>. This study also reported that, plasma copper levels, unlike liver copper content, did not reflect dietary copper intake.  

#'''Effects on reproduction''': In adult female cats fed low dietary copper levels (3 or 6 mg/kg DM as cupric sulphate) had an effect on reproductive efficiency, increasing the time for successful conception compared with control cats fed copper at 10 mg/kg diet. However pregnancy rates were unaffected<ref name="Fascetti">Fascetti, AJ, Morris, JG, Rogers, QR (1998). “Dietary copper influences reproductive efficiency of queens”. J Nutr. 128:2590S-2592S.</ref><ref>Fascetti, AJ, Rogers, QR, Morris, JG (2000). “Dietary copper influences reproduction in cats”. J Nutr. 130:1287-1290.</ref>. This study also reported that, plasma copper levels, unlike liver copper content, did not reflect dietary copper intake.  

==5.  Toxicity==

==Toxicity==

===Dog:===  

===Dog:===  

Unlike the dog, there appears to be little or no information on the toxic effects of copper in cats.

Unlike the dog, there appears to be little or no information on the toxic effects of copper in cats.

==6. Dietary Sources==

==Dietary Sources==

Copper is found in reasonable amounts in some cereal sources such as soya flour and wheat germ meal. The best animal source is liver, especially beef or lambs’ liver. There are moderate amounts in some meat meals. However, to ensure adequate dietary contents, manufactured dog and cat foods are usually supplemented with inorganic copper salts such as cupric sulphate, cupric carbonate and cupric chloride. Copper chelates of amino acids such as lysine are also good sources of bioavailable copper. However, cupric oxide is not suitable as a source of dietary copper for dogs and cats. In one study where adult cats were fed a diet containing cupric oxide as the supplement they showed clear signs of copper inadequacy, even though the dietary copper content was identical to an adequate diet where the copper was supplied by cupric sulphate<ref name="Fascetti"/>.  

Copper is found in reasonable amounts in some cereal sources such as soya flour and wheat germ meal. The best animal source is liver, especially beef or lambs’ liver. There are moderate amounts in some meat meals. However, to ensure adequate dietary contents, manufactured dog and cat foods are usually supplemented with inorganic copper salts such as cupric sulphate, cupric carbonate and cupric chloride. Copper chelates of amino acids such as lysine are also good sources of bioavailable copper. However, cupric oxide is not suitable as a source of dietary copper for dogs and cats. In one study where adult cats were fed a diet containing cupric oxide as the supplement they showed clear signs of copper inadequacy, even though the dietary copper content was identical to an adequate diet where the copper was supplied by cupric sulphate<ref name="Fascetti"/>.