Teores de iodo na dieta e função da tireóide em gatos

Abstract

The excess of iodine and its deficiency can cause thyroid dysfunction depending on the dose of iodine and of the preconditions of the gland. Given the assumption that commercial diets for cats contain amounts of iodine beyond the minimum needs of the species, this study was proposed to evaluate the content of iodine in wet and dry commercial diets for adult cats in relation to requirements for species and morphometric aspects and functional thyroid gland in cats fed high levels of iodine. In 29 samples of food for adult cats, marketed in Rio de Janeiro iodine levels ranged between 2.7 and 3.4 mg / kg / MS in dry food and 2.9 to 4.0 mg / kg / MS in wet food. The means between wet and dry rations were higher and the estimated daily consumption was above the recent estimates for adult cats (NRC, 2006). Ultrasound examination in the mean total glandular volume was equal to 0.143 cm3 being greater in the left thyroid (0.075 cm3) compared to the right (0.068 cm3). The concentrations of total thyroxine (T4) and total triiodothyronine (T3) in 20 cats studied varied between 0.62 and 1.51 mg / dl, with an average of 1.056 ± 1.77 mg / dl for T4 and 0, 10 to 0.45 ng / ml for T3 were low compared to the baseline. Changes in blood count and serum biochemistry were not significant to describe the changes secondary to thyroid iodine excess, and were not consistent in differentiating the condition of euthyroid sick. The hypothesis that excessive intake of iodine daily can contribute to the development of hyperthyroidism was not supported by the values of T4 and total T3 and sonographic findings, whereas in hyperthyroidism the thyroid glands were hypertrophic and the values of T4 and T3 were higher.