RESUMEN

Maximum serum thyroxine (T4) and triiodothyronine (T3) levels of healthy calves were seen at 1 day after birth, and thereafter rapidly decreased until 5 days after birth. They stabilized until 2 weeks after birth, then gradually decreased until 4 weeks after birth. Serum T4 levels of calves with endemic goiter tended to be lower than those of healthy ones, but showed similar levels to those of adult cows. T3 levels of calves with goiter were similar to those of healthy ones, but showed higher variation. T4/T3 ratio of calves with goiter were significantly lower than those of healthy ones and adult cows. While individual levels of serum T4 and T3 at just after birth could not be considered as a diagnostic index, the T4/T3 ratio could be adopted as a diagnostic index of endemic goiter.

Asunto(s)

RESUMEN

High incidence of goitre in human together with low level of iodine in water and cow milk have been observed in Southern Poland (Table I). Therefore, iodine deficiency was considered as the only cause of goiter development. The correlation coefficient between iodine concentration in water and cow milk was r = 0.76 (Fig. 1) and indicate the possibility of iodine determination in milk instead of water. The iodine determination in milk reflects the level of iodine in water as well as in food, a negative correlation has been obtained between goitre incidence in human and iodine concentration in water (r = 0.43) (Fig. 2.). A low correlation coefficient suggest that iodine is not a solely factor responsible for goitre development. Studies on cows have indicated that thiocyanate may have effect on goitre development as well. There has been found higher concentration of thiocyanate (SCN) in blood plasma and in enlarged thyroids (Table II). Thiocyanate belongs to goitrogenic compounds and its main source are the plants of Brassica species widely cultivated in southern Poland. It has been found that cows fed with Brassica plants have high level of SCN both in blood and milk with no alteration of plasma iodine level. The transfer of iodine from plasma to milk is only slightly affected (Table III). The level of SCN in the thyroid depends on its plasma concentration; the calculated correlation coefficient is r = 0.88 (Fig. 3). Enhanced thyrotropin (TSH) secretion (during goitrogenesis) may be accompanied by increased accumulation of SCN in the thyroid (like iodide) and reduced oxidation to SO4 (unlike iodide) (Fig. 4). Therefore we postulated that TSH may be partly responsible for increased SCN level in goitrous thyroids. The question arise whether increased ingestion of SCN does really potentiate iodine deficiency and goitrogenic process in animals breeding in southern Poland. For explanation some additionally experiments were performed on laboratory animals. It have been observed that enhanced level of plasma SCN following feeding with Brassica plants increased proportionally the goitrogenic action as well as the accumulation of 131J by the thyroid and its conversion into organic form (Fig. 5). The latter data was confirmed by positive correlation between thyroxine and plasma SCN levels in sheep (r = 0.49), (Fig. 6) Thiocyanate like other monovalent anions suppress goitrogenic effect of propylthiouracil. However, anti-goitrogenic properties of SCN depends on normal iodine ingestion (Fig. 7).(ABSTRACT TRUNCATED AT 400 WORDS)

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

Endemic goiter still occurs in several European countries. Alimentary iodine deficiency could be proved as the main cause of endemic prevalence. Extensive epidemiologic surveys showed the great medical and economical impact of this matter for the GDR. Over 200 million Marks might be spent for diagnosis and treatment of thyroid patients per year. Also in the field of veterinary medicine and animal production iodine deficiency plays an important role. Under the conditions of iodine deficiency the fodder containing nitrate and glucosinolates (e.g. bruised rape extraction) results in additional goitrogenic effects (so-called indirect or relative iodine deficiency). Due to iodine deficiency disorders considerable losses of yields in cattle, pigs and sheep occurred. The content of iodine in animal products used for human nutrition was subsequently low. Considering the ecological implication of these problems an Interdisciplinary Iodine Commission within the Society for Endocrinology and Diseases of Metabolism of the GDR was established. Together with the governement authorities it worked out corresponding recommendations for the prophylaxis and control of its efficiency. In 1986 the iodination of most of the packed salt (32 mg KIO3/kg = = 19 mg I/kg) and the administration of iodinated mineral mixtures for the animal production were started for pigs in the whole territory of GDR and for cattle in the southern counties of the GDR only. These activities have been accompanied by information of TV as well as in the newspapers and medical journals. Thus, an improved supply of iodine to the population through iodinated table salt and animal products can be taken into account. The efficiency of these prophylactic measures is controlled interdisciplinarily.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

Twenty-two mineral elements are known to be essential for animal life. These are calcium, phosphorus, sulphur, potassium, sodium, chlorine, magnesium, iron, iodine, copper, manganese, zinc, cobalt, molybdenum, selenium, chromium, tin, vanadium, fluorine, silicon, nickel and arsenic. Naturally occurring and man-made dietary imbalances of many of these elements and their interactions with other minerals are described and their functions and requirements by farm animals are outlined. The nature and importance of metabolic interactions among the mineral elements are discussed and the important concept stressed that there is no single minimum requirement or safe tolerance of a particular mineral, but a series of such minimum requirements and safe tolerances depending on the extent to which other minerals with which it interacts is present or absent from the diet. Radioactive tracer elements are shown to be of great value in the determination of mineral nutrient availability to the animal and for following mineral metabolic movements in the body. They are also shown to have considerable potential for the diagnosis of mineral imbalances. Various in vivo and in vitro techniques, involving both radioactive and stable tracers developed for the early diagnosis of mineral deficiencies are described and the strengths and weaknesses of such techniques in comparison with standard biochemical tests, are discussed. The need for further critical studies with isotopic tracers in the detection and diagnosis of mineral imbalances is emphasized. The main types of biochemical criteria used in the diagnosis of mineral deficiencies and excesses are given, with appropriate examples of their use.

Asunto(s)

RESUMEN

Comparison of certain features of endemic goitre in the Khumbu district of Nepal and Piedmont is reported. Cases in the younger generations were observed in both areas. In Khumbu, the incidence of goitre in schoolchildren was 75% and cases were even noted in children who had been receiving iodine prophylactic management (injections of iodised oil: 500-1000 mg/yr) for at least three years. The iodine content of drinking water and the most commonly eaten foods was determined. Values were very low and a daily intake of not more than 30 mug was calculated. The findings are in line with metabolic studies carried out by other workers in Upper Khumbu. While it is clear that ambiental iodine deficiency is much higher in Khumbu than in those areas of Piedmont where goitre is most markedly endemic, the inadequacy of preventive iodine administration measures, and environmental features common to both areas, suggest that iodine deficiency is a concomitant factor and not the prime cause of endemic goitre.

Asunto(s)

Asunto(s)