2 trials were conducted with female rats to investigate in which way the level of dietary Cu influenced the level of Cu concentrations in rat milk. The trials were made to establish whether data on the Cu content of milk might be used as indication of the level and state of Cu supply to the animal. In the period of colostrum formation the Cu content of the milk was shown to be clearly dependent on the level of dietary Cu. In later periods of lactation Cu concentrations in the milk (from 2 mg of Cu per kg of diet) were found to be unaffected by the Cu content of the diet. Constant Cu concentrations of between 2.5 to 3.0 mg per kg of milk were noted in this period. It was only in cases of extreme Cu deficiency (0.5 mg/kg of diet) that soon after parturition the Cu values decreased to and remained at a very low level of 1 mg per kg of milk. Generally, colostrum contained 4-6 times more Cu than ordinary milk (in all groups).

Animal Nutritional Physiological Phenomena↗

PubMed1976

Effect of varying vitamin B6 intake of early-weaned piglets on urinary xanthurenic and kynurenic acid excretion, serum transaminase activity and urea concentration.

In a bipartite rearing experiment (day 1-24 and 24-45) 72 early-weaned piglets were used to study the effect of varying dietary vitamin B6 contents on renal excretion of xanthurenic and kynurenic acid after a tryptophan load, on urea concentration and activities of two transaminases in serum at the end of each period. The animals, divided into 6 groups, were fed ad libitum a prestarter and a starter in period I and II, respectively, each containing 0.5, 1.2, 2.0, 2.8, 3.5 or 6.6 mg vitamin B6 per kg dry matter. The urinary xanthurenic acid excretion was elevated especially at the vitamin B6 supply of 0.5 ppm and rose severalfold with increasing depletion time (period II). In both periods, the smallest amount was excreted by piglets supplemented with 2.8 ppm. In comparison to groups B (1.2 ppm) and C (2.0 ppm), their average excretion rate was reduced by 29% and 15%, respectively, in period I and by 50% and 22%, respectively, in period II. Analogously to xanthurenic acid, the smallest amount of kynurenic acid was excreted by group D (2.8 ppm). Starting from the lowest vitamin B6 supply, the activity of SGPT showed an almost linear increase in both experimental periods. In contrast, SGOT already reached an upper activity level with the dietary vitamin B6 content of 3.5 and 2.8 ppm at the end of period I and II, respectively. The concentration of serum urea was influenced only by the lowest vitamin B6 supply of 0.5 ppm.

Alanine Transaminase↗

PubMed1975

[Changes in the nutrient and energy content in defined parts of the veal calf (author's transl)].

In a study on the nutrient and energy content of defined parts of the body, five veal calves each were slaughtered at the start and at the end of two fattening periods with liquid diet. The whole body weight of the three groups of veal calves averaged 56, 96, and 151 kg. All body organs and parts resulting from slaughtering and partitioning were weighed, divided among 11 groups of cuts, and analyzed for dry matter, crude protein, ether extract, ash and energy. The various cuts showed different weight gains in relation to live weight. Blood, hide and gastrointestinal tract and also total meat increased about proportionally to live weight, the innards and bones developed more slowly. During the 12-week fattening period the percentage of total meat of the carcass increased from 68 to 72, the percentage of adipose tissue from 3 to 8. Over the same period the percentage of bones decreased from 26 to 19. The groups of organs and tissues showed considerable differences in nutrient content. With an increase in ether extract concentration from 39 to 69% of fresh matter during fattening, the adipose tissue of finished calves contained 13 times the amount of ether extract of animals at the start of fattening. The deposition of fat in the skeleton, in contrast to the soft tissues, already reached the maximum level in the weight range under 100 kg. Among the four defined groups of lean meat there were no major differences in crude protein and ash. In the total meat crude protein content declined from 20.4 to 19.3%, ash content from 1.7 to 1.3% of fresh matter during fattening. The total protein content amounting to 13.2 kg in the group after finishing reached 2.7 times the level of the inital content. At the same time the fat content of the total meat increased from 2.4% initially to 7.7% at the end. The highest level found was 11.3% in the lean meat of the chest/abdominal part. In the total meat about 2.8 times as much fat was retained in the second period of fattening than in the first period.

Adipose Tissue↗

PubMed1975

[On the complex formation of proteins with cu ions under acidic conditions].

In order to determine the influence of copper additives on the protein digestibility, the complex formation of proteins with Cu ions under acidic conditions (pH=2.2) was investigated. Isolated soja-protein (300 mg) resp. pepsin was mixed with 10 mumol (2.49 mg) CuSO4-5H2O and dialysed against low molecular complexing agents with increasing affinity towards copper ions. The experiments with soja-protein showed, that most of the Cu ions dialysed (97% of total Cu2+ content) without any addition of complexing agents, pepsin, however, had a lower percentage (83% of total Cu2+ content). The remaining copper ions in pepsin could only be removed by alanin and ammonium-tetramethylendithiocarbamate. Therefore it is concluded, that in the acidic range Cu ions only form complexes with pepsin, but not with soja-protein. This effect is due to the very low isoelectric point of pepsin. The determination of iron, nickel, and zinc in native proteins revealed, that at pH=2.2 iron and nickel are stronger linked to pepsin than to soja-protein; only zinc was loosely bound to both proteins.

Copper↗

PubMed1975

Carbonic anhydrase activity and erythrocyte count in the blood of zinc-deficient rats.

Eighteen male Sprague Dawley rats were divided into three groups. They were offered a semisynthetic casein diet containing either 1.2 mg Zn/kg dry matter (depletion group) or 100 mg Zn/kg dry matter (ad libitum and pair-fed control groups). At the beginning and on the 5th and 24th day of the experiment, blood was removed from a tail vein by incision to determine erythrocyte count and carbonic anhydrase activity. The zinc-depleted animals displayed a great increase in erythrocytes during the course of the experiment as compared to the ad libitum control animals. The erythrocyte counts of the pair-fed animals were also increased after 24 days on experiment, but remained significantly lower than those of the depleted animals. The activity of the carbonic anhydrase per ml blood was the same in all groups at the end of the experiment. When, however, the carbonic anhydrase activity was expressed per unit of erythrocytes, the zinc-deficient animals had a significantly lower enzyme activity than both the ad libitum and the pair-fed control rats.

Animals↗

PubMed1975

[Effect of zinc deficiency on glucose tolerance].

18 male rats (Sprague Dawley) were divided into 3 groups each receiving the following amounts of dietary zinc: 2 mg/kg in the depletion group and 100 mg/kg in both the ad libitum-fed control group and in the pair-fed control group. After 34 days of experiment the rats were fasted for 12 hrs and then received 50 mg of glucose per 60 g of body weight injected into the femoral muscle. With equal intial glucose concentrations Zn-depleted rats exhibited a significantly reduce glucose tolerance compared with that of the ad libitum-fed control animals. The reduced glucose tolerance in the Zn-deficient animals does, in this case, not arise as a result of the reduced food intake and the resulting weakened condition of the animals. This was shown by results obtained with the pair-fed animals exhibiting a significantly more stable glucose tolerance than the Zn-depleted rats, which was even more rigid than that of the ad libitum-fed controls.

Animal Feed↗

PubMed1975

[Excretion of zinc in lactating cows receiving various supply of zinc].

Studies were carried out with 5 lactating cows receiving a semisynthetic diet to trace the pattern of zinc excretion in the faeces, urine and milk under conditions of Zn depletion and repletion. Faecal Zn concentrations were found to be drastically reduced during a 6-week period of Zn depletion. The Zn supply to the animals at different levels of Zn repletion (varying between 22 mg and 436 mg Zn per kg) was well reflected in the corresponding faecal Zn concentrations. Similarly, faecal Zn excretion expressed as the percentage of Zn supplied with the diet was shown to change with the level of Zn supply. In the range between 6 mg and 54 m Zn per kg of dietary dry matter the level of relative faecal Zn excretion increased from 42% to 56% whereas with higher Zn supplements (up to 436 mg/kg) only slight increases (up to 60%) were observed. This indicates that the organism exhibits a strong tendency to maintain a physiological balance; this tendency is all the more pronounced with increasing Zn depletion; thus after 19 weeks of Zn depletion as little as 25% of the administered amount of Zn was excreted in the faeces. The average minimum of urinary Zn concentrations was 0.25 mg Zn per litre. The Zn concentrations in urine were not found to be dependent on the Zn supply. The level of relative Zn excretion in the milk was markedly increased despite the reduced concentrations of milk Zn during the periods of Zn deficiency. At the beginning of Zn depletion rather more zinc was released with the milk than was taken up with the Zn deficient diet. The mean proportion of milk Zn in the total amount of dietary Zn over the 6-week depletion period was 91%. With Zn amounts of 22 mg, 54 mg, 87 mg, 108 mg, 130 mg and 436 mg per kg of diet 23.7%, 13.1%, 12.9%, 5.7%, 4.3%, and 1.7% of the dietary Zn were excreted with the milk. Thus, a relative decrease of Zn excretion in the milk was observed, i.e. relative to the level of Zn supplementation.

Animal Feed↗

PubMed1975

[Determination of metabolic availability of zinc and estimation of zinc requirements through changes in the activity of metallo-zinc enzymes].

Data on the zinc requirements of animals vary widely with the type of diet or kind of zinc compound considered, as they are dependent on the kind of definition and estimation of mineral requirements used which, in turn, are based on the analytical content of the mineral in the diet. Actually, requirements for a particular trace element are the same for any diet provided differences in the rate of absorption and metabolic availability of the element are taken into consideration. A suggestion is made in the present paper to utilize changes in the activity of different metallo-zinc enzymes as a method for determining the degree of metabolic availability of zinc. Within the framework of a repletion trial young male rats were fed a semisynthetic casein diet containing 1.2 ppm of zinc for a 14-day period of zinc depletion followed by a 15-day repletion period during which the rats received a diet containing 4.5 ppm or 12 ppm of zinc. In this trial the pattern of activity of the alkaline phosphatase in serum and in the femoral bones was studied and the level of pancreatic carboxypeptidase A and B was estimated. The data thus obtained were compared with those of pair-fed control animals and control animals fed a libitum. (96 ppm of dietary zinc). The results of the present trial show the metabolic availability of zinc can be determined by measuring the level of activity of these metallo-zinc enzymes. A suitable model was established. Moreover, attempts have been made to show in which way the zinc demands of growing, full-grown, pregnant and lactating animals may be estimated by measuring changes in the degree of activity of these metallo-zinc enzymes. A definition is, in this case, given by that amount of zinc which allows for an optimum activity of the different metallo-zinc enzymes. Such data are applicable only to a particular diet or are valid only for a particular zinc compound. Principally, it is much better to relate the Zn requirements of the animal to the level of absorbable and metabolically available zinc. The present model has been suggested to provide a possibility for measuring the metabolic availability of zinc in the body.

Alkaline Phosphatase↗

PubMed1975

[The effectiveness of a single oral administration of iron depot tablets in iron deficiency anemia of baby pigs].

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Administration, Oral↗

PubMed1975

[Changes in zinc content of the cow's milk with varying zinc supply. 14. Metabolism of zinc in the animal organism].

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Animal Feed↗

PubMed1975

[Zinc status in bones of dairy cows (Tuber coxae) in zinc depletion and repletion. 15. Metabolism of zinc in the animal organism].

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Animal Feed↗

PubMed1975

[Serum and plasma insulin levels in zinc-deficient rats following glucose stimulation].

In three experiments male Sprague-Dawley rats depleted in zinc (2 ppm dietary zinc) for 30 to 35 days had greatly reduced serum insulin levels when compared to ad libitum-fed control animals (100 ppm dietary zinc) but in only one of the experiments when compared to pair-fed control animals (100 ppm dietary zinc) which also had reduced insulin levels. Similarly, in a following study the plasma insulin levels of zinc-deficient animals depleted for 20 days were not different from those of pair-weight control animals (100 ppm dietary zinc). Fifteen minutes after one i.m. glucose injection and 15 minutes after two glucose injections, two hours apart, the zinc-deficient rats showed a higher blood glucose level than the pair-weight controls. The plasma insulin contents also increased after the glucose stimulation but were not significantly different between the zinc-deficient and the zinc-supplemented groups. It is assumed that zinc deficiency lowers the physiological potency of insulin and thereby effects a reduced glucose homeostasis of zinc-deficient rats. This could also be demonstrated by additional studies with zinc-deficient rats which secreted 76 per cent more insulin after a Rastinon injection than control animals though they showed about the same bloodglucose levels.

Animals↗

PubMed1975

[Vitamin E concentration in blood and tissues of growing pigs fed on varying DL-a-Tocopherylacetate supplements].

The concentration of tocopherols in blood serum, liver and adipose tissue of growing pigs with different vitamin E supply was estimated gas-chromatographically. The animals were fed with a practical diet, supplemented with 0, 5, 15, 25 and 95 ppm dl-alpha-tocopheryl acetate (groups I-V). Based on a naturally vitamin E content of 7.4 and 8.6 mg per kg of the diet the control animals (group I) showed very low tocopherol concentrations of 0.5 mug per ml serum and about 1 mug per g tissue. No clinical vitamin E-deficiency symptoms were observed. The increasing alpha-tocopherol supplements raised the vitamin E contents in a proportional rate, and with high vitamin E supplies the highest quantities of tocopherols were stored in the adipose tissue. When the alpha-tocopherol content in the diet was raised by 1 mg, the concentration in the serum increased by 0.033 mug per ml, in the liver by 0.094 and in the adipose tissue by 0.129 mug per g, respectively (gamma = 0.99). This increase in the concentrations was strongly linear and can be interpreted by constant rates of absorption and retention of alpha-tocopherol in the present investigation. The growth of the pigs was no influenced by the different alpha-tocopherol supplements.

Adipose Tissue↗

PubMed1975

[Experimental animal studies on the absorption of zinc from various parts of the small intestine and various zinc compounds].

The absorption of zinc in different parts of the small intestine and from various Zn compounds was studied in situ, using rats. Segments of equal length from the duodenum, jejunum and ileum were ligated. Into these loops, 65Zn-ZnC12 or 65Zn-ZnC12 with an excess of histidine at a molar ratio of 1:250 and 1:2,000 was injected. The uptake of 65Zn was measured in blood, plasma and different organs after 1 h of absorption. The absorption of zinc was significantly greatest from the duodenum, followed by the jejunum and ileum. The jejunum differed only slightly from the ileum in the absorption capacity for zinc. A 250-fold excess of histidine did not alter the Zn absorption in comparison to ZnC12. There were, however, distinct interactions between the site of Zn absorption and the Zn compound at the molar ratio of zinc:histidine of 1:2,000. With this addition of excess histidine, zinc was absorbed just as well from the jejunum as from the duodenum. The 2,000-fold addition of histidine raised the Zn absorption from the jejunum by about 40% in comparison to ZnC12.

Animals↗