Iodine deficiency animals

One major problem in these studies has been the development of a suitable low iodine diet. It was essential that the diet be satisfactory apart from the one particular nutrient, iodine, so that any non-specific effects could be eliminated. This was achieved with both species showing normal fetal growth on the control diets which consisted of the iodine deficient diet with an iodine supplement. This meant that differences between the control and iodine deficient animals could, with confidence, be attributed to the iodine deficiency. 

Nonmetallic elements predominating in the ash are phosphorus (700 g in the human body), sulfur (175 g), and chlorine (105 g). Not only are these three elements essential to all living cells but also selenium, fluorine, silicon (Box 4-B), iodine, and boron are needed by higher animals and boron by plants (Fig. 1-17). Iodine deficiency may affect one billion human beings and may cause 20 million cases per year of cretinism, or less severe brain damage.158... 

It has been estimated that in 1990 iodine deficiency affected almost one-third of the world s population and represented the greatest single cause of preventable brain damage and mental retardation. Fortification of all salt for animal and human consumption has been chosen as the preferred method for the prevention of iodine... 

Except for much greater Cl accumulation in soils of arid regions, the soil chemistry of I and Br resembles that of Cl, except that I and Br are retained more strongly, especially by acid soils. The major input of I to soils appears to be atmospheric. Endemic iodine deficiency (goiter in humans) occurs in mountainous and continental areas isolated from the sea. Fortunately, supplementing NaCl with small amounts of I effectively supplies the I required in animal diets. Iodide and Br are both potentially toxic, but no natural cases have been reported. Bromide reactions in soils have been investigated as a tracer for die movement of water, nitrate, and soil solutions in soils. 

The excessive consumption of soybean and its products has been considered goitrogenic in humans and animals. Several researchers have reported the induction of goitre in iodine-deficient rats maintained on a soybean diet [133, 134, 135], Tn some cases, the extreme intake of soybean has been correlated with cancer. Thus, Kimura et al reported an increase of up to 40% in thyroid carcinoma in rats fed on iodine-deficient defatted soybean [136],... 

Iodine deficiency causes goiter in animals (and cretinism in humans) (Meng 1992, Anke et al. 2000). Iodine is a component of the important thyroid hormones, and... 

The interrelationship among iodine deficiency, selenium deficiency and the activity of thyroid hormones (thyroxine 5 -deiodi-nase-1) was identified in the early 1990 s, when iodine and selenium were found to be necessary for reducing T4 in the cell-active T3 in animals and man (Behne et al. 1988, 1990, Arthur etal. 1990, Arthur 1992, Beckett et al. 1987, 1993, Berry et al. 1991, Larsen and Berry 1995). 

Without iodine supplements in the form of marine fishmeal or mineral mixtures, the farm animals of most countries worldwide would suffer of iodine deficiency. Germany and most industrially developed countries unconsciously supply farm animals (and in turn the population) with iodine by fertilizing the land with Chile saltpeter, which has a high iodine content. During World War I, the importation of Chile saltpeter to Europe was stopped, and thereafter synthetic nitrogen containing no iodine was produced worldwide. Consequently, iodine deficiencies in both animals and man reap-... 

The natural iodine offer of animals and man without iodine supplementation greatly varies with distance from the seaside, the geological origin of the site, the eating habits and the specific iodine contents of the various foods and beverages (Table 9-4.15). The danger of an iodine deficiency is most severe in grazing ruminants (wild and domestic) and lowest in carnivores. Animals and people with mixed diets are also... 

The pituitary and brain, as well as brown adipose tissue, contain DI2 and DI3, which catalyze 5 - and 5-deiodination, respectively. Selenium deficiency alone has no effect on thyroid weight in rats, whereas iodine deficiency results in a 60% increase, and concurrent iodine and selenium deficiency results in a thyroid weight 148% above that of control animals. The principal physiological role of DI2 is the local intracellular production of T3. The role of DI3 has been proposed to protect fetal tissue from high levels of T3 and T4 during development by converting them to r T3 and r T4, respectively (Sunde 1997) (r = reverse). 

Iodine also appears in the milk of animals and women, at level which correlate with those in the blood. In humans and cows, iodine levels in milk were found to vary between 10pgL in case of iodine deficiency and > 100 pgL with a high iodine intake. 

Essentiality in monogastric animals In horses, goiter appears in foals which may be stillborn or exhibit extreme weakness at birth which results in an inability to stand and to suckle the mare. Iodine-deficient mares may exhibit abnormal estrus cycles, and males may have decreased libido (Cunha 1990). 

Geoppel B, Anke M and Hennig A (1988) Possibilities of diagnosing iodine deficiency in ruminants. In Hurley LS etal. eds. Trace Elements in Man and Animal - 6, TEMA, pp. 661-662. Plenum Press New York and London. 

Potter BJ, Mano MT, Balling GB, Rogers PS, Martin DM and Hetzel BS (1981) Reversal of brain retardation in iodine-deficient fetal sheep. In Howell I, McC, Gawthome JM, White CL, eds. Trace Element Metabolism in Man and Animals, pp. 313-315. Springer Verlag Berlin, Heidelberg, New York. 

Iodine is an essential element in humans and other mammals, which is used for the synthesis of the thyroid hormones triiodothyronine (T3) and thyroxine (T4). These hormones play a prominent role in the metabolism of most cells of the organism and in the process of early growth and development of most organs, especially brain (Anderson et al., 2000). Besides T3 and T4, reverse T3 (rT3), monoiodotyrosine (MIT), and diiodotyrosine (DIT) are also synthesized and distributed in the body of humans and animals, but only T3 and T4 have a biological function. Iodine in the human body mainly comes through dietary and water intake, and inhalation of atmospheric iodine. Due to low concentrations of iodine in the air (10—20ng/m ), food and water intake form the major source of iodine for adults, while for infants it is milk. The concentration of iodine in foodstuffs is directly related to that in the environment where the foods come from. Iodine deficiency disorders are mainly found in places where the concentration of iodine in the soil and drinking water is very low. In the water, foodsmffs, and... 

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