DAFS-25k impact on cattle’s thyroid hormonal status

Abstract

The paper studies the impact of selenium organic preparation DAFS-25k on thyroid capacity in pregnant cows. A stud farm which the work is done in is a biogeochemical province distinguished by a sharp deficit of selenium and iodine in the diet. DAFS-25k had been implanted into the animals subcutaneously during 1 month 30 days before the predicted calving. A sterile 0.6 % DAFS-25k oil solution was used in doses containing 2 mg/cow/day, 6 mg/cow/day and 12 mg/cow/day. It was found that the cows' diet is deficient in iodine and selenium by 63 and 82 % respectively. Daily use of selenium in DAFS-25k in the dose range causes a decrease in the concentration of free thyroxine due to deiodination activating by selenium dependent deiodinases of the first and second types. Consequently, there is a progressive increase in the blood content of total triiodothyronine in all experimental animals as relating to the background values. In this case, the concentration of thyroid-stimulating hormone decreases in blood serum by the 30 th day according to the principle of negative feedback. In control animals, an increase in the serum concentration of thyroid-stimulating hormone reached the point 1.8 by the 30 th day, total triiodothyronine increased by 14 and 19 % by the 21 st day and the 30 th day respectively, while the concentration of free thyroxine was reduced by 19 % by the 30 th day. The use of selenium in the setting of iodine deficiency leads to aggravation of iodine deficiency.

Detection of some hormonal and enzymatic disorders associated to experimentally iodine induced hyperthyrodism.

“…One of the diseases that can be caused due to administration of excess iodine is the iodine induced hyperthyroidism (IIH) disease. The disease is caused due to excess iodine intake mainly in iodine deficient areas in spite of the thyroid gland adaption for storing high amounts of iodine for maintenance of (THs) normal levels [14,5,15]. Administration of excess iodine is one of the obstacles that face geriatrics and paediatrics due to subjection to daily or promptly supplementation of iodine through food or drugs.…”