70% to 80% of the iodine in animals exists in the thyroid gland, as an important component of thyroid hormones, and a small amount of iodine is distributed in tissues and organs such as muscles, skin and bones.
iodineinorganic state and organic stateTwo forms exist. The inorganic state mainly includes potassium iodide, potassium iodate, calcium iodate, etc.
Among themPotassium iodideEasy to be oxidized, sublimation to iodine, poor stability. In the production process, the phenomenon of yellowing of packaging bags is mainly caused by iodine sublimation.Potassium iodateSoluble in water, under the action of light and water, will accelerate the decomposition, acidic substances, metal salts, etc. will affect its stability.Calcium IodateIt is a common feed iodine additive with good stability and high bioavailability.
Organic iodine is mainlyDiiodosalicylic acid, ethylenediamine dihydroiodateWait. Although diiodosalicylic acid is easy to absorb, most of it will be excreted from urine with low biological potency. Ethylenediamine dihydroiodate reacts with sulfate to free elemental iodine under high temperature conditions in storage, which will stimulate animal intestinal mucosa or corrode containers.
Absorption, Utilization and Metabolism of Iodine
The main site of iodine absorption in monogastric animals is the small intestine, followed by the stomach.
Iodine in the digestive tract of animals is mainlyiodine ionThe form is absorbed and utilized in the thyroid gland. In the thyroid gland, the process of iodine ion absorption and utilization can be simply described:
①(iodine activated)-- Iodine ions are oxidized to iodine by peroxidase;②(iodinated)-- Binding to tyrosine residues in thyroglobulin and to diiodotyrosine;③（condensation)-- after condensation,Triiodothyronine and serum thyroxine are generated by the action of proteolytic enzymes, ④(Release)-Then through the blood circulation into the body tissue to play a physiological function.
Absorption and utilization of iodine ions in the thyroid gland
TG: Thyroglobulin;T: Tyrosine;
MIT: monoiodotyrosine; DIT: diiodotyrosine;
T4: tetraiodothyronine (thyroid hormone);
T3: Triiodothyronine
After iodine is absorbed and utilized, most of it is excreted through urine, and a small part of it is excreted through feces, sweat glands and animal products.
