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Calcium
/ calcium sources
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1.
Functions
Calcium is one of the most abundant elements in the body and
is often the major cation in the diet. More than 90% of the
body’s calcium is located in the skeleton; bones and teeth.
Calcium is also important in cellular metabolism, blood clotting,
enzyme activation and neuromuscular action. Ionic calcium in
blood plasma is maintained precisely by a large number of regulatory
processes, centering around the calcium homeostatic hormones.
Calcium is very important for eggshell formation and milk secretion.
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3.
Quality and selection parameters
3.1 Particle size, solubility and bioavailability
Particle size and solubility are important parameters. The
optimal size and solubility depend on the type of feed (poultry,
pigs, ruminants, compound feed, premix, complementary feed).
Limestone is available in various particle sizes from fine
flour to coarse granules.
The particle shape of oyster shells is flaky and is available
in various grades.
The
colours white, grey and yellowish can also be taken into consideration
for several feed productions, especially premixes and mineral
supplements.
The calcium bioavailability is another parameter.
The main inorganic sources have a relative biological availability
of 95 to 100%. Calcium in plant raw materials, often as a complex
with oxalate, has a relatively low bioavailability.
3.2
Purity
The purity (undesirable substances) conforms to the EU directives.
In calcium sources these undesirable substances are extremely
low or absent.
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