Introduction
Copper levels are widely distributed in nature but are
generally not among the most abundant elements. Copper
and molybdenum are often discussed together due to their
interaction.
Metabolism
Copper is often not so easily absorbed by natural means
into the system and is influenced by the delivered form.
Absorption is controlled by homeostasis and regulated
by need. Absorbed copper is transported loosely bound
to serum albumin. The liver is the major storage organ
for copper. Approximately 90% of copper is in plasma
in the metalloprotein ceruloplasmin, copper is transported
from the liver to tissues as ceruloplasmin.
Physiological
functions
Functions include cellular respiration, bone formation,
cardiac function, connective tissue development, myelination
of the spinal cord, keratinization and tissue pigmentation.
Copper component of important metalloenzymes
is:
- Cytochrome oxidase
- Lysol oxidase
- Superoxide dismutase
- Dopamine-hydroxylase
- Tyrosinase
(others less well defined)
Along with iron, copper is needed for hemoglobin synthesis,
copper is needed for iron absorption and mobilisation.
Copper is part of cytochrome oxidase, in the respiratory
chain, a reduction of oxygen 02
to H20.
Central
nervous system
An imbalance of copper can result in swayback (enzootic
ataxia), caused by cytochrome oxidase resulting in incomplete
myelin formation. Myelin, composed largely of phospholid
is needed for normal nerve impulse transmission. Copper
is also needed for normal levels of neurotransmitters,
dopamine and norepinephrine.
Reproduction
A deficiency in copper can result in reproductive failure.
Immune
system
Copper is vital for the immune system and a deficiency
in copper status effects, T and B cells, neutrophils
and macrophages. Impaired humoral immune response (antibody-producing
cells) mechanism can result via superoxide dismutase
( a copper, zinc and manganese dependant enzyme) and
related to phagocytes.
Requirements
Copper can be influenced by iron, molybdenum, sulphur,
zinc levels and protein source. Copper content in pasture
can be influenced by soil pH and soil calcium levels.
Young growing horses have a higher copper requirement.
Deficiency
- Relationship between
low serum copper and haemorrhaging in aged parturient
mares.
- With age possibly
less absorption or reduced ability to mobilise
- Deterioration in
the ability of the immune system to function properly.
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