|
|
|
| |
| |
Iodine
/ iodine sources
-
Functions
Iodine is essential for animals and is present in tissues (0.1
micrograms per gram body weight), but concentrated in the thyroid
gland (400 micrograms per gram body weight).
The main role of iodine is as a component of thyroid hormones
(tri-iodotyronine and tetra-iodotyronine [thyroxine], which
are synthesised in the thyroid gland using iodine extracted
from the blood-stream. Iodine-containing thyroid hormones regulate
metabolism and maintain body functions (body temperature, growth
and development, milk production and reproduction).
Iodine deficiency rapidly leads to a reduction in thyroid hormone
synthesis, so that the bodily functions controlled by such hormones
are less effective. For example stock born from mothers with
an iodine deficient diet have the following symptoms :
calves, lambs or piglets may be stillborn, or very weak at birth.
affected breeding poultry lay fewer eggs with poor hatchability.
hatched chicks are small and weak.
In addition to the above effects, iodine deficiency is visibly
indicated by a swollen thyroid gland, or goitre.
-
Stability
Iodate salts are stable during storage and the iodine content
of feed will remain unchanged with time; thereby ensuring that
the animal will receive the required dose of iodine (40 mg/kg
of feed) from its feed.
Sodium and potassium iodides lose iodine very rapidly when in
contact with other minerals, or in a moist atmosphere. The physical
properties of these two iodides cause absorption of water that
binds the crystals together, forming lumps that are a major
disadvantage when blending together a feed formulation.
-
Free
flowing properties
The fine crystals of iodate salts have an attraction, similar
to that of flour, that need to be overcome in order to generate
a free-flowing powder. Inclusion of approximately 0.1 % of an
additive is sufficient to overcome this attraction and to produce
an iodate that is free flowing and easy to blend.
Iodide salts are stabilised by addition of stearates that act
as a barrier between the crystals and air-borne moisture. This
additive is intended to prevent decomposition to release iodine
and maintain free-flowing properties.
|
| |
|
