Trace Mineral Function
The primary
physiological role of copper is as an enzyme activator and enzyme constituent.
In addition, it has a basic function in iron metabolism and red blood
cell maturation, and is important in the immune system.
Function of Copper in Egg Production
Copper deficiencies affect the synthesis of eggshell membranes. In fact,
these membranes are made from fibers of protein quite similar to elastin
(rich in the amino acids proline, histidine and cystine) with linkages
derived from lysine. This structure and composition give these membranes
resistance and elasticity. The synthesis of these linkages is made by
hydroxylation of lysine by a copper-containing enzyme, lysyl oxidase.
When there is a deficiency in copper, degradation of the synthesis of
these fibers is noticed with increasing permeability of membranes and
increase in the size of the egg, leading finally to considerable disruption
in eggshell formation.
Moreover, it is important to remember the role of copper
in keratin synthesis. A copper deficiency will have negative consequences
on the oviduct cells and epithelium quality. The role of copper in the
formation of ovarian blood vessels is also important. A copper deficiency
would create hemorrhages and may result in the presence of blood spots
in the yolk.
Antagonists to Copper and Recommended Dietary Inclusion Rates
Recommended dietary inclusion is between 8 and 25 ppm. Ten ppm is the
most common level used, but it is important to note that zinc, calcium
and iron reduce copper availability. In addition, producers feeding diets
utilizing by-product feeds (for instance corn gluten) are cautioned about
possible antagonisms (because of sulfur) and may need to adjust accordingly
the dietary level and/or source of copper.
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