[Testing of extracted particles from winter rapeseed with different glucosinolate levels in swine with special reference to the iodine supply. 2. Thyroid hormone status, histomorphometric findings and iodine content of the thyroid gland]

In the experiment, 2 x 12 growing pigs received 19 or 6.7 mmol glucosinolates + aglucones/kg feed via conventional rapeseed meal (RSM) or RSM of a newly bred variety. These pigs and 24 littermates pair fed with a soya bean meal (SBM) diet were subdivided in groups of 4 animals each. Their diet contained either no supplementary iodine or an iodine supplementation of up to 1 mg/kg feed. In the RSM and SBM groups the lack of additional iodine lowered the serum T4 and T3 content below the detection limit and caused goitre with about 1 mg iodine in the total thyroid. The SBM diet with 0.0625 mg supplementary iodine/kg increased the serum T4 level and reversed the thyroid enlargement but not that of epithelial cells. The hypothyroidism (goitre and serum T4 level approximately 10 nmol/l) still existed in the case of this iodine dosage together with the RSM of the newly bred variety. A serum T4 level comparable to that of the animals fed SBM was only reached by supplementing the low glucosinolate diet with 0.25 mg iodine/kg feed. The iodine content of the thyroid, however, was reduced by 50 per cent. Though thyroid and epithelial cells were enlarged, this enlargement was not so obvious as in animals exposed to higher glucosinolate level. In spite of 1 mg supplementary iodine/kg feed, the feeding of the conventional RSM resulted in a lower serum T4 level a reduced thyroid iodine content and the enlargement of thyroid and that of epithelial cells. Compared to the high glucosinolate RSM, a significantly lower antithyroid effect of the low glucosinolate RSM was found in pigs with iodine supply. The degree of thyroid enlargement and the serum T4 level were the criteria.

Trace element intake (zinc, manganese, copper, molybdenum, iodine and nickel) of humans in Thuringia and Brandenburg of the Fed. Rep. of Germany

The daily dry matter intake of 56 test persons between 20 and 60 years of age from four geographic groups (Wusterhausen and Vetschau in Brandenburg; Jena and Bad Langensalza in Thuringia) was registered on 7 consecutive days by means of the duplicate method. The Zn, Mn, Cu, Mo, I and Ni content of food and beverage dry matter and the daily intake of these trace elements were determined. During the test period, the ration contained 24-29 mg zinc, 6.8-9.2 mg manganese, 1.9-2.6 mg copper, 0.17-0.22 mg molybdenum, 0.10-0.18 mg iodine and 0.36-0.68 mg nickel per kg dry matter. The adults consumed 6.7-11.0 mg zinc, 2.0-3.8 mg manganese, 0.54-0.92 mg copper, 47-89 micrograms molybdenum, 30-67 micrograms iodine and 111-256 micrograms nickel per day. The living area had an effect on the Mn, I and Ni intake. The higher dry matter intake resulted in a better trace element supply of male test persons. The copper, molybdenum and iodine requirement recommended by the WHO was not met.

Effect of varying glucosinolate and iodine intake via rapeseed meal diets on serum thyroid hormone level and total iodine in the thyroid in growing pigs

In a trial with 50 fattening pigs (20 kg initial body weight), the effect of untreated rapeseed meal (RSM) (148 mmol glucosinolates and aglucones per kg dry matter) on the thyroid was compared with RSM treated with Cu2+ (9.5 mmol glucosinolates and aglucones per kg dry matter) and soybean meal (SBM). The diets containing 8% RSM were supplemented with 0.0625-1.0 and the SBM diet (control) with 0.125 mg iodine kg-1 (I). In comparison with SBM fed control, RSM treatment with Cu2+ resulted in a complete normalization of feed intake and growth. Only untreated RSM without I supplementation depressed performance and resulted in symptoms of I deficiency, but the thyroid and liver weight were also increased and the serum T4 content was significantly reduced in animals which were given RSM not supplemented with I, but treated with Cu2+. In young pigs (4 weeks) a plateau of the serum T4 content was achieved from 0.5 mg I kg-1 of the RSM diet onwards. In contrast, when the concentration of goitrogens was reduced by the treatment with Cu2+, the serum T4 level was increased significantly in groups fed with 0.125 mg I kg-1 diet and more. In older pigs (15 weeks) neither the content of goitrogens nor the I dosage affected the serum T4 level. On the other hand, the I content in the thyroid was a good indicator of the different goitrogenicity of the diet in the case of a low I supply. The present investigations show that pig diets with RSM (greater than 10 mmol glucosinolates and aglucones kg-1) should contain at least 0.5 mg I kg-1, but 0.1 mg supplementary I per kg is sufficient in diets without or with a low content (less than 1 mmol glucosinolates and aglucones per kg-1) of antithyroid compounds.

The cadmium status of horses from central Europe depending on breed, sex, age and living area

The Cd status of animals is best reflected by kidneys and much worse by liver and hair. Breed (heavy- and warm-blooded horses) only took an insignificant effect on the Cd content of kidneys and liver. On the average, however, warm-blooded horses stored more Cd than heavy ones. Geldings from Cd-exposed living areas accumulated insignificantly more Cd in liver, kidneys and hair than mares. The influence of age on the Cd content of kidneys and liver of Cd-exposed horses was significant. The Cd exposure of a living area was very well reflected by kidneys and liver. On the average, horses from two areas with nonferrous metal smelting stored 1000 mg Cd/kg kidney dry matter and 100 to 200 mg Cd/kg liver dry matter. The highest Cd concentration of the kidneys of horses amounted to 2.6 and 2.3 g/kg dry matter, resp.

The effect of selenium deficiency on the feed consumption and growth of goats

The feed consumption of goats was only reduced after considerable Se depletion. The conversion of Se-depleted animals to an Se-rich ration increased feed consumption within one day. An intrauterine Se deficiency (less than 38 micrograms Se/kg DM of the ration) did not induce intrauterine growth depression in kids. Se depletion led to a highly significant postnatal growth depression which increased with advancing Se depletion both during the lactation period and after weaning.

The effect of selenium deficiency on reproduction and milk performance of goats

Even with a high vitamin E offer, Se deficiency (less than 38 micrograms/kg DM of the ration) led to a 33% lower conception rate (P less than 0.05) in goats and to a greater than 50% lower number of kids on the 91st day of life. The Se deficiency reduced the milk production significantly by 23% during the first 56 days of lactation, the milk fat production by 11% and the milk protein production by 12%.

[The effect of iodized mineral substance mixtures for cattle and swine on iodine requirements and struma prevention]

In the southern districts of the GDR the calculated iodine uptake of adults was 80 micrograms/day before the iodine supplementation of the mixtures of mineral substances and the packet kitchen salt. The iodine supplementation of the mixtures of mineral substances for cattle and pig tripled the iodine content of the milk or increased it fivefold in the county of Erfurt and doubled the proportion of iodine of the meat, the inner parts and the sausage produced from them. In a daily consumption of 0.31 of milk and 250 g of meat and sausage a surplus supply of 35 micrograms of iodine for adults was calculated in the southern counties of the GDR. The 35 micrograms of iodine for the future necessary for covering the demand of iodine are certainly delivered by the iodized kitchen salt.

The influence of sulphur, molybdenum and cadmium exposure on the growth of goat, cattle and pig

In growing billy goats, bulls and heifers, the supplementation of 10 g elementary S/kg ration dry matter reduced the daily weight gain by about 15%. The offer of 10 g S and 10 mg Mo/kg ration did not intensify growth depression. It occurred, however, when 10 g S were applied together with 3 mg Cd. Under these conditions, fattening bulls gained 19% less weight. The monogastric pig reacted less sensitively to the same exposure. The growth depression only reached about 10% and remained insignificantly. On the other hand, pigs with 10 g S and 3 mg Cd gained 17% less weight (p less than 0.05). The supplementation of 20 g elementary S/kg reduced their growth dramatically. These pigs only gained 89 g weight per day. The effect of S (and Mo or Cd) supplementation was mainly due to decreased feed consumption.

[Iodine deficiency in ruminants. 1. The iodine content of feed, plants and drinking water]

Dependent on the species, feedstuffs and plants differ considerably in their iodine content. Among the I-poorest feedstuffs there are grain concentrates, extracted soybean and rapeseed oil meals, mixed feed (without I-containing mineral mixture) and grasses. The I content of the plants decreases with proceeding growth. The I intake of ruminants via vegetable feed and drinking water is affected by the distance of the site from the seaside and the geological origin of the soil material. Ruminants get considerably less iodine via feedstuffs and water in the southern territory of the GDR than in the central and northern areas. Therefore, mineral mixtures for cattle and sheep are supplemented with 18 mg KIO3 per kg mixture in the southern districts. The I analysis of 205 charges of mineral mixtures revealed only a mean I content of 7 (3.8-11.3) mg per kg mixture.

Nickel--an essential element

Nickel is necessary for the biosynthesis of the hydrogenase, carbon monoxide dehydrogenase, and of factor F 430, found in a number of genera of bacteria. Urease from jack beans and several species of plants is also a nickel protein. These plant enzyme systems can affect animals via the microbiological digestion of food in the rumen. Nickel is a constituent part of all organs of vertebrates. Its absorption can be controlled. Low nickel offers reduce growth; this is particularly true of intra-uterine development. Such offers also decrease the life expectancy of reproducing animals. Nickel deficiency is accompanied by histological and biochemical changes and reduced iron resorption and leads to anaemia. It can disturb the incorporation of calcium into skeleton and lead to parakeratosis-like damage, which finds expression in disturbed zinc metabolism. Nickel deficiency results in lower activities of different dehydrogenases and transaminases and, above all, of alpha-amylase, and particularly affects carbohydrate metabolism. A marked decrease in metabolism was observed in the case of the energy sources fat, glucose, and glycogen. Nickel therefore performs a vital function in metabolism: it is an essential element. The nickel requirements of human beings and animals amount to less than 500 micrograms/kg and are probably even considerably lower. It therefore follows that, in view of the available nickel offer, primary nickel deficiency in human beings and animals can be excluded, at least in the present state of knowledge. On the other hand, it should be remembered that, 25 years after the discovery of the essentiality of manganese, this element was included among the trace elements of academic importance only, whereas today it is a feed additive.

[Iodine metabolism. 2. Effect of iodine deficiency on reproduction and the development of progeny of goats and miniature pigs]

The influence of J-deficiency on reproduction was tested in model experiments with goats and mini pigs, partly through several reproduction cycles including the descendants after intra-uterine depletion as well. The effect of 0.05 mg J/kg dry matter in the concentrated feed (total ration 0.03)--0.04 mg J/kg dry matter) for goats was a diminished success of first inseminations, a higher frequency of abortions, high mortality and poorer development of the kids. All J-deficiency goats and kids suffered from hypertrophy of the thyroid gland, half of all J-deficiency kids were born hairless. Concerning the mini pigs, 0.06 mg J/kg dry matter even after intra-uterine depletion had no detectable influence either on conception or the mortality and development of the piglets. The thyroid gland of all deficiency pigs was enlarged, however. The hypertrophy of the thyroid gland makes it easy to diagnose J-deficiency visually.

[Investigation of iodine metabolism. 1. The influence of iodine deficiency of the feed consumption and the development of the live weight of goats and dwarf pigs]

With goats and dwarf pigs two experiments were made with semi-synthetic rations. The influence of insufficient (0.05 resp. 0.06 ppm) and sufficient (0.42 resp. 0.56 ppm) supply with iodine on feed consumption and the development of the live weight during the growth period and gestation was investigated. While iodine deficiency resulted in diminished feed consumption and a growth depression of the goats, a negative influence on feed consumption and the live weight increase of the dwarf pigs could not be detected, feed expenditure per kg weight increase, however, was distinctly higher.

[Excessive iron administration to sheep. 2. The effect on the iron, copper, zinc and manganese level in different organs]

Lambs received 250, 1000 and 1750 mg Fe per kg concentrate dry matter. The Fe-supplementations caused the Fe-levels of spleen, liver, kidneys and ribs to rise significantly. Liver and spleen reflected most markedly the high Fe-supply. The Fe-supplementation reduced the Cu-content in the liver and the share of Zn in the kidneys. The Mn-content of all body parts analysed was not significantly influenced by Fe-supplementation.

[Nickel--an essential trace element. 3. Effect of nickel deficiency on reproductive performance in female animals]

A total of 26 Ni-deficient (less than 100 ppm Ni in the ration) breeding goats and their 30 kids and 24 corresponding control goats with 37 kids were used to investigate, over 6 experimental years, the influence of Ni-deficiency on the reproductive performance until weaning. Following the same arrangement, 7 and 6 mini sows, respectively, and their piglets (71 and 67) were studied. The following statistically secured results were obtained. Ni-deficiency resulted in reduced pregnancy rates (after one insemination) in animals that had revealed clear estrus symptoms. This caused delayed pregnancies and birth of offspring. The conception and abortion rates, the number of offspring and the sex ratio were not influenced significantly by Ni-deficiency. Intra-uterine Ni-deficiency reduced the birth weights and caused lower weight gains during the suckling period. Its influence proved stronger in the kids as compared to the mini piglets. Ni-deficiency caused the mortality of the offspring during the suckling period to increase significantly. The losses in the Ni-deficient kids and mini piglets were by 41 and 51%, respectively, higher than in the corresponding control animals.

[Nickel--an essential trace element. 1. Influence of the supply of nickel on live weight gains, food consumption and body composition of growing pigs and goats]

Pigs and goats were used in long-term trials to investigate in which way supplements of 100 mug Ni per kg of a semisynthetic diet (control rations: 10 mg Ni per kg of the diet) would influence the rate of weight gains and food consumption and the body composition of the animals. A significant decline in the rate of weight increase was noted in the Ni-deficient animals. Ni-supplements added to the diet (10 mg/kg) increased the weight gains by 21% (goats) and 13% (pigs). In the present trial goats showed a more sensitive response to Ni-deficiency than pigs. Ni-deficiency did not affect the food consumption of neither the growing goats nor the growing pits. It was only during their lactation period that the Ni-deficient goats showed a statistically well-established decrease in food consumption. The level of Ni supply did not affect the crude protein, crude fat and crude ash content of the pigs.

[Supply of trace elements to ruminants in the German Democratic Republic. 3. Supply of zinc]

The supply of zinc to ruminants as influenced by and depending upon the geological origin of soils was investigated using the hair test and the technique of indicator plants. A total of 1276 samples of red meadow clover and 3022 samples of red field clover and 4184 hair specimens from cows were analyzed. The following statistically well-established results were obtained which appear to be generalizable: Red meadow clover contained significantly more Zn than red field clover (48 ppm/38 ppm). Red meadow clover and field clover grown on loamy soils (59%), weathered soils of less (59%), red sandstone (57%) basalt (53%), shell limestone (47%) and Keuper (41%) contained only 59%-41% of the amount of Zn found in indicator plants that were grown in locations were the highest Zn level (weathered soils of porphyry). Zn concentrations in red meadow and field clover grown on soils of the same geological origin correlated with r = 0.87. A positive correlation (B = 0.53) was found to exit between the relative proportions of Zn contained in indicator plants grown on a particular soil and the proportions of Zn contained in hair specimens from Zn-deficient cows (less than 100 ppm of Zn). The largest number of hair specimens containing less than 100 ppm of Zn were found in cows from areas with soils of basalt (17%), and loess (18%), areas with loamy soils (24%), and sandy diluvial soils (25%), or with alluvial pastures (23%), or with soils of Keuper (27%), shell limestone (22%) or red sandstone (29%). Ruminants in these areas are liable to suffer from Zn deficiencies.

[Trace element supply to ruminants in the German Democratic Republic. 2. Supply of copper]

The supply of copper to ruminants as influenced by and depending on the geological origin of soils was investigated in different parts of the GDR by using the hair test. Red clovers (meadow clover and field clover) were used as indicator plants. The following results were obtained: Data on the Cu content of clovers grown on soils of the same geological origin were found to correlate with r = 0,81. After eliminating the effects of Cu antagonists resulting from industrial pollution it was possible to establish numerical relations (B = 0.39 and B = 0.89) between the relative values (specific for the particular location) for the Cu content of the indicator plants and the percentage of cows suffering from Cu deficiencies (6.0 and 5.0 ppm Cu in hair). The lowest percentages of Cu supply to the ruminants (established on the basis of the Cu content of red clovers) were found on diluvial sandy soils, glacial loams and peat and bog soils whereas the highest percentages of Cu were found on weathered soils (of phyllite, gneiss, shell limestone, red marl soils and porphyry). Secondary Cu deficiencies in ruminants may arise, independent of the geological origin of the soil material, in places exposed to the main direction of the winds from major industrial areas (emission of SO2, Cd and Mo). Due to primary and/or secondary deficiencies the supply of Cu to ruminants in various locations (syenite, granite, red sandstone, gneiss, loess; peat soils, diluvial sandy soils) may be insufficient. A detailed description is given of areas where Cu deficiency is likely to occur and recommendations are given on how to use mineral mixtures containing a high proportion of Cu (1.00 g Cu per kg).