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Summary The role of β-carotene in reproduction was investigated in gilts assigned to three dietary supplementations: VA (4000 IU vitamin A); VA + VA (4000 IU + 8300 IU); VA + BC (4000 IU + 100 mg β-carotene) per kg diet for 14 weeks. Gilts were slaughtered at day 12 of gestation. In the VA + BC group, number of corpora lutea was lowest, but the number of embryos was greatest, resulting in a non-significant decreased prenatal mortality(p

Investigations with 15N'-labelled urea were carried out to find out the influence of the amount of fibre on the reflux of 15N' into the caecum to take part in the caecal metabolism. Two pelleted diets, containing 9.7% (group 1 with 23% oat hulls) and 2.2% (Group 2 without oat hulls) crude fibre, with urea with 60 atom% 15N-excess (15N) used as marker were given to three White New Zealand rabbits each group. Group 1 and 2 consumed 109 and 72 g fresh matter per rabbit and day, respectively. Daily 15N'-intake per rabbit was 307 mg in group 1 and 279 mg in group 2. Most of 15N' was eliminated directly via the urine. The daily faecal excretion in group 1 and 2 was 5.3 and 2.3 mg 15N', respectively. Only about 20 to 30% of 15N' and volatile fatty acids in the caecum and higher amounts of 15N' in muscles were found. The animals of this group consumed nearly the total amount of faeces by caecotrophy. Therefore 24 g of group 2 was still satisfying compared to 33 g live weight gain/rabbit and day of group 1. It is concluded that the animals of group 2 could compensate the low fibre level within a period of about 20 days by a more efficient utilization, the consumption of crude protein and starch being 18 and 12% lower than in group 1, respectively. Feed intake and health status were not evidently affected. The results are in contradiction to the common knowledge.

In commercial pig fattening, copper is added to the feed in amounts that greatly exceed the requirements of the animals. On the one hand, this improves weight gain, but on the other, as we were able to recently prove, the retention of the heavy metal cadmium rises in the kidney, in the liver and in muscle. In a feeding experiment with female and male castrated piglets, we tried to counter the copper-induced rise in cadmium (175 mg Cu/kg feed) by adding zinc or vitamin C to the diet. While addition of 100 or 200 mg zinc per kg of diet had no influence, the addition of 1000 mg vitamin C reduced the elevated cadmium values in the kidneys and livers to values only determined with a low copper supplementation of 35 mg copper per kg of feed. This positive vitamin C effect not only occurs in cases of high copper supplementation (175 mg Cu/kg feed); when the pigs were given only 35 mg copper per kg of feed, vitamin C also reduced the cadmium content in the organs by 35 to 40%. This indicates that vitamin C improves the quality of food gained from animals for human consumption in both conditions.

During a 6-wk feeding trial, effects of low dietary deoxynivalenol (DON; 0, 0.1, 1 and 10 ppm) on food consumption and weight gain were investigated in male mice. Food intake was similar in all four dietary groups. Weight gain in the group receiving 10 ppm DON was significantly (P less than 0.01) reduced. At the end of the feeding period, test animals were sacrificed and absorption of water, D-glucose, L-leucine, L-tryptophan, 5-methyltetrahydrofolic acid and iron was measured in isolated perfused jejunal segments in vitro. No effects were observed on absorption of water, leucine, tryptophan and iron. However, at a dietary DON concentration of 10 ppm, a slightly but significantly (P less than 0.05) reduced transfer of glucose was measured. Furthermore, transfer as well as tissue accumulation of 5-methyltetrahydrofolic acid in the jejunal segment were both significantly decreased up to 50%. Heavy metal and trace element content was determined in liver, kidney and small intestine. Manganese and molybdenum content in liver tissue was reduced with a DON concentration of 10 ppm in the diet. The findings indicate that subchronic ingestion of DON, in concentrations occurring in contaminated food and feed, results in an impairment of intestinal transfer and uptake of nutrients such as glucose and 5-methyltetrahydrofolic acid.

A bioassay of vitamin K is described, based on the prothrombin clotting time of 3-week-old, vitamin-K-depleted, and cumatetralyl-sensitized male broiler chicks, using a homologous thrombokinase preparation. With this test it could be shown that the diacetate and dibutyrate esters of menadiol are vitamin-K-active. The bioactivity of menadione from these menadiolesters amounted to about 70% of the standard menadione from a coated menadione sodium bisulfite (Dohyfral). Menadiol seems to be temperature-resistant under such conditions, whereby two uncoated MSB preparations lost about 60% of their activity.

In a nutritional tolerance study 36 young dogs were fed over 52 weeks high or low purine diets at an average paired feeding intake of 0.6 and 80 mg purine-N/MJ per day. The high purine diet resulted in a significant decrease of growth rate by -23% (Beagles) and -38% (Dalmatians) and of feed efficiency (-29 and -42%). The fasting levels of allantoin, uric acid and uracil in blood plasma were significantly increased. During the experiment a metabolic adaptation to the high purine diet decreased the plasma concentrations of uric acid, uracil and in part of allantoin. The high purine diet effected a significant increase of Km (2.5-fold) and of Vmax (1.6-fold) of uric transport through the erythrocyte membrane. The results documented disadvantageous effects of high purine nutrition during juvenile development.

In a series of experiments with a total of 1480 veal calves, different aspects of treating calves with anabolic steroids were examined. The anabolics used were 17beta-estradiol (E), trenbolone acetate (T), progesterone (P), testosterone (Te), C+T, E+P, E+Te and zeranole (Z). The N-retention was estimated by examining the urea: creatinine ratio in single urine specimens during the course of two feeding trials. Increased gain due to the treatment with E (20 mg implanted/calf) + P (200 mg) and Te (200 mg), respectively, E + T (140 mg) or Z (36 mg) was during the whole experimental period. The extra gain, due to anabolics seems to contain even more protein. This conclusion may be supported by the crude protein content of meat samples. The antibody production of a total of 311 male and female calves was investigated after the application of the following steroids: E (20 mg), T (200 mg), T (200 mg), E + T, P (200 mg), Te (200 mg), E + P, E + Te, and Z. Eleven days after the implantation of the steroids the animals were immunized with alumprecipitated human serumalbumin. Antibody-titres were determined by the Antigen-Binding-Capacity Test on day 14 following immunization. In nearly all groups the antibody-titres of female calves exceeded those of male calves on the average by 75%. The immune response of all experimental groups did not differ significantly from that of the corresponding control groups. However, the results indicate that both E + T and its single components E and T exert an immunodepressive effect in male calves. While the humoral antibody formation in the calf appears not to be influenced by anabolic steroids, it cannot be decided presently whether these substances effect cell-mediated immune reactions and/or unspecific mechanisms of resistance. When estradiol (20, 200, and 500 mg) and trenbolone acetate (140, 1400, 3500 mg) alone and in combination were implanted in female calves, blood glucose, GOT, GPT, alkaline phosphatase, LDH, cholesterine and bilirubine; Hb, PVC, quick value; urine density and pH were not affected by treatment. Some criteria of the mineral metabolism (Ca- and P-levels in serum and bone) was not altered by treatment. Trenbolone (1 400 and 3 500 mg), especially with estradiol, caused a decrease of the serum Mg-level and of the Mg-deposition in the bone. It is discussed that Trenbolone affects the dig-metabolism of calves. Some morphological findings are worth mentioning. The weight of uterus was not affected by the different doses of E or T, but a combination E + T led to a surprising weight increase. The proliferation of uterine glandular cells was responsible for the increased uterine size. The lumen of uterus was partially filled with a watery liquid. The reduction of the ovarian weight was accompanied by a diminution of follicular size for all treated calves, most evident for E (200, 500 mg) + T (1400, 3500 mg). A decrease in the number of follicles was also found for these two groups. T (3500 mg) caused an abnormal size of the clitoris and led to a reduction of the size of thymus.