Overview

Forms of Iodine & Absorption Metabolism

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.

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.

Factors affecting the absorption of iodine in the body

Calcium in the diet can hinder the absorption of iodine,Inhibits the synthesis of thyroxineAccelerate the discharge of iodine. in the dietPhosphorus and iodine have a synergistic effect.

The cassava and corn in the diet contain thiocyanate, which can be reversed into thiocyanate in the gastrointestinal tract,Competitive inhibition of iodide transport to the thyroidIncreased iodine excretion.

The main sources of iodine in the feed industry are calcium iodate, ethylenediamine dihydroiodate, potassium iodide, etc. Among themCalcium Iodateis the most widely used source of iodine in the feed industry,This is because of itsHigh purity and bioavailabilityand chemical in premix mineral feed or livestock feedLow reactivity, good stability.

Application of Iodine in Animal Production

Adding iodine to the dietMaintain the normal metabolism of energy, regulate the metabolism of livestock and poultry, promote the growth and development of animal body, promote the growth of fur, improve the utilization rate of feed, improve the reproductive performance and iodine content in animal productsWait.

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