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Biomedical subjects

M Kreuzer

Publications and source records attributed to M Kreuzer.

71 records · Page 4Linked to original sources
PubMed1995

Response of renal orotic acid and creatinine to treatments affecting metabolic protein supply of ruminants.

90 urine samples obtained in three lamb trials and one experiment using adult wethers were analyzed for their contents of orotic acid and creatinine. The average daily excretion of orotic acid accounted for 0.5 mg to 1.5 mg (35 micrograms to 130 micrograms/W0.75) with a high individual variation. Correlation coefficients between orotic acid and other urinary constituents were low indicating an entirely different response to metabolic variations. There was only a weak relationship to live weight, protein retention and rumen fluid traits. Defaunation reduced the orotic acid excretion (significant in the adult wethers) whereas the addition of rumen-protected lysine as well as the use of different dietary carbohydrate sources were without effect. The urinary excretion of creatinine increased with live weight and age from 0.4 g/d in the 20 kg lambs to 1.7 g/d in the adult 53 kg wethers. The correlations with live weight were close whereas the apparently negative correlation with protein retention was not real as could be evaluated by calculation of the partial correlations. There was a close correlation of creatinine with total N, urea and allantoin. Neither defaunation nor rumen-protected lysine and the kind of carbohydrate source had significant effects on creatinine. The use of orotic acid and creatinine as indicators of metabolic disorders were discussed. Easy application in practical diagnosis without quantitative urine collection might be possible by the determination of orotic acid in the milk of cows and of the creatinine/N ratio in urine.

Allantoin↗
PubMed1994

[Age and sex dependent variation in the content of Fe, Zn, Cu and Mn in different body parts and their retention in fattening pigs].

The concentrations of Fe, Zn, Cu and Mn were determined in meat, inner organs, blood and residual carcass in a total of 24 barrows and gilts of 60 kg and 100 kg of live weight, respectively. the finisher diet contained 192 ppm Fe, 113 ppm Zn, 18 ppm Cu and 65 ppm Mn with, as calculated, a great proportion originating from the mineral supplement. During growth, the contents of Fe, Cu and Mn were significantly reduced. No sex differences occurred. In the lean meat of the 100 kg pigs, common values accounting for 1.1 mg Fe, 2.8 mg Zn and 0.05 mg Cu per 100 g were analyzed. The manganese concentration of 0.01 mg per 100 g, however, was considerably lower as the corresponding figure from nutrient tables. In the finishing period, the animals retained per animal and day about 18 mg Fe, 15 mg Zn and 0.2 mg Cu. Mn retention was not significantly different from zero. The low utilization rates calculated from these data can be partly explained by the moderately excessive supply in this fattening period. In order to reduce the trace element load of the soils, a considerably lower tolerance of excessive trace element contents in finisher diets has to be developed.

Aging↗
PubMed1994

Interactions of cobalt and iron in absorption and retention.

The effects of supplementary oral cobalt and iron, as well as the interaction between both at the absorption site, fecal and urinary excretion as well as the retention of these trace elements were determined by using four diets containing either 9 or 63 micrograms/kg of Co and 48 or 446 mg/kg of Fe over a period of 19 days in a total of 24 rats. Retention was calculated by the balance technique and by the comparative slaughter technique. After one day, fecal as well as urinary excretion of both elements had already responded to the dietary treatments, with constant values being reached after approximately three days. Cobalt excretion was enhanced by supplementary cobalt; fecal excretion, too, was increased by supplementary iron; whereas urinary excretion was decreased in both cases. Additional iron significantly inhibited the absorption of cobalt in both dietary cobalt treatments. The lower rate of absorption in the groups receiving 446 mg Fe instead of 48 mg of Fe per kg diet resulted in a decreased renal excretion of cobalt. Consequently, the effect of iron on the retention of cobalt was lower than on absorption. This suggests that interactions between the two elements only take place at the site of absorption. Because of the low dietary cobalt concentration as compared to the iron contents of the diets, no effect of cobalt on iron absorption and excretion occurred. Differences in iron balance were only observed between both dietary concentrations, showing a higher absolute but a lower relative absorption as well as retention in the groups fed further Fe.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Endogenous iron excretion. A quantitative means to control iron metabolism?

The effects of supplemental oral (0, 40, and 400 ppm) and parenteral iron (0 and 2.72 mg Fe iv given initially as a single dose) on iron absorption, excretion, and retention were determined in 30 rats. Endogenous fecal iron excretion was determined by the radioisotope dilution technique after im injection of 80 kBq Fe-59, using blood and certain body tissues as reference sources for the estimation of the specific activity (Bq Fe-59/micrograms Fe) of endogenous iron. The basal diet contained 3.6 ppm Fe. Fe(III)-hydroxide-polymaltose was used as the sole iron source in oral, iv, and im iron treatments. Iron balance as determined from day 14 to 20 of the experiment was not significantly affected by iv iron administration. Nevertheless, a temporarily reduced retention should have occurred, since differences in final body iron contents were lower than 2.72 mg, as compared to the respective untreated groups. Apparent iron absorption and iron retention increased with surplus oral iron, and the efficiency rates were highest with adequate iron supply (40 ppm). True absorption rates of iron were similar without any, and with 40 ppm Fe amounting 40 to 50% of the intake. In the iron deficient rats, half of the actually absorbed iron (about 16 micrograms/d) was lost by endogenous fecal re-excretion, and another 3 micrograms/d by the urinary route. Endogenous loss with feces and with urine increased with further oral iron supply, but at a considerably lower rate as total fecal excretion. Parenterally administered iron did not affect endogenous loss at all. The results indicate that endogenous excretion cannot be regarded as a means to eliminate excessive iron, and might actually be an inevitable loss.

Absorption↗
PubMed1991

Cellulose fermentation capacity of the hindgut and nitrogen turnover in the hindgut of sows as evaluated by oral and intracecal supply of purified cellulose.

Adult sows fed a constant amount of a basal diet received purified cellulose either orally at levels of 0 and 475 g/animal.d (Experiment 1) or intracecally at levels of 0, 285, 570 and 855 g/animal.d (Experiment 2). Each experiment consisted of subsequent periods of faeces and urine collection with the animals re-allocated to the treatments each time. With that, a total of 36 observations on each parameter was achieved. The faecal samples were analyzed for the contents of organic matter, cell wall carbohydrates and various nitrogen fractions such as bacterial N and undigested dietary N. Furthermore, N balance, urinary allantoin excretion and plasma urea concentrations were determined. In a preliminary study, the effects of freeze-drying and of shaking of the faecal samples as suspensions with water (in order to release bacteria from fibre) on content and composition of faecal nitrogen had turned out to be reproducible. Cellulose significantly enhanced faecal nitrogen loss whereas N retention was not affected due to the counteraction of urinary N loss. Plasma urea concentration reflected the situation with urinary N. The proportion of undigested dietary N and of water-soluble protein in total faecal N was somewhat increased by cellulose at cost of the bacterial N proportion which accounted for about 72% of total N on average. Urinary allantoin did not respond to the higher bacterial activity in the hindgut in the presence of supplementary cellulose. Cellulose significantly decreased the apparent N digestibility by on average about 3 percentage units per 100 g of supplementary cellulose. True N digestibility was also reduced by cellulose but did not go below 95%. The supplementary cellulose was fermented in the hindgut at similar rates of on average about 60% regardless of the route of administration. The almost 100 g of native cellulose incorporated in the basal diets were lignified by about 20%, and that is why they were fermented at a rate of only about 30%. The rate of fermentation was only slightly decreasing with increasing amounts of supplementary cellulose, and a daily quantity of 564 g (11 g/W0.75) cellulose was fermented on average if the highest level of cellulose was provided. This was within a range exclusively reported for easily-fermentable carbohydrates but was achieved in the case of cellulose only at a consistently higher level of supply. The true efficiency of bacterial protein synthesis was 5.2 g bacterial protein/100 g supplementary cellulose on average. The apparent efficiency was 60% higher averaging 8.4 g bacterial protein/100 g further apparently fermented organic matter.

Animals↗
PubMed1990

Quantitative effects of allogeneic small-bowel transplantation on nutrient digestion and on body protein balance as determined in vivo in rats.

Heterotopic and orthotopic small-bowel allotransplantation was carried out in Wistar rats using grafts reduced to one-half of the original length. Portocaval venous anastomoses and intestinal end-to-end anastomoses were performed. Animals either with complete or with partially reduced native small-bowel served as control. In a total of 51 rats, 88 quantitative in vivo measurements of apparent digestion and absorption of dietary dry matter, organic matter, energy, protein, fat, total ash, and glucose were carried out. Body protein retention was calculated from intake and losses with feces and urine. The digestion trials comprised 8 days of adaptation and 10 days of continual recording of nutrient balance data. In experiments 1 and 2, digestibility coefficients were obtained before and after transplantation within the same animals, untreated or initially treated with cyclosporine A after surgery. Similar groups of rats untreated, with partial resection and with transplantation of the small-bowel, followed by temporary cyclosporine treatment, were used in experiment 3. In experiment 4, rats with transplanted intestines from experiments 1 and 2 were subjected to a further digestion trial 4 to 6 months after the respective first trial. With transplantation of the small intestine, apparent digestion and absorption of nutrients, as well as protein retention, tended to be lower. Significant depression occurred in the digestion of fat and ash. In long-term survivors all parameters decreased further. The adverse effects on fat and ash digestion seemed to be pronounced when rejection occurred. Fecal fat excretion might therefore be an indication of dysfunction of small-bowel grafts. Digestion was less imparied if cyclosporine was applied, and part of the effects on digestion and protein balance could be attributed to the shortened bowel.

Animals↗
PubMed1990

Biliary flow rate and concentration of Fe, Cu and Mn as affected by enteral or parenteral Ni supply.

Five and three bile duct cannulated 45 kg pigs were used in two experiments to evaluate the effects of nickel on the biliary excretion of iron, copper and manganese. In control periods the animals consumed 1.5 mg Ni per day (1 mg/kg diet), and in the respective treatment periods they further received 90 mg Ni per day (60 mg/kg diet) orally or 1.5 mg Ni per day intravenously. Oral supplementation of nickel had no significant effect on biliary iron, whereas the secretion rate of copper was increased by about 50%, and manganese secretion was reduced to about 50% of the control value. Parenteral administration of nickel had no significant effect on biliary iron, copper and manganese secretion. Iron and copper secretion rates were highest after feeding, whereas the pattern of manganese secretion was characterized by a predominant noctural peak irrespective of the treatments in both experiments.

Animals↗
PubMed1988

[Amino acid pattern in the bodies and several organs of broilers fed different provisions with tryptophan and neutral amino acids].

Carcasses and organs of 36 broiler chicks originating from an extensive fattening experiment with differing proportions of tryptophan (0.65 and 0.93 g/16 g N) to the neutral amino acids (15.2, 18.3 and 22.0 g/16 g N) in feed were analyzed for amino acid contents. Aside from the whole carcasses, a selected muscle (M. fibularis longus), liver, small intestine, and brain were prepared from the animals and analyzed. The organ weights differed according to the live-weights with the exception of the brain, where no group differences were measured. The patterns of amino acids of carcasses and organs remained nearly constant with differing amino acid supply. The only remarkable effect was the increase of the proportions of proline and hydroxyproline in the carcass protein from 6.4 to 7.4 and from 1.6 to 1.8%, respectively, with the higher tryptophan supply indicating increasing proportions of connective tissue. No relationship between weight gain and collagen content (calculated from hydroxyproline content) could be detected. The frequently supposed antagonism between tryptophan and the neutral amino acids, especially at the border of blood and brain, caused no reduction in tryptophan content of brain with increasing supply of neutral amino acids. There was, however, a significant depression of the development of the animals and the other inner organs.

Amino Acids↗
PubMed1987

[The nutritive defaunation of the rumen in ruminants].

Two promising methods to remove the ciliate protozoa of the stomach of ruminants by simple alterations in the feeding system were examined in vivo with lambs and heifers in the present investigation. The use of pelleted concentrates fed ad libitum and of milk, especially of milk fat (cream), turned out to be effective against protozoa when given after few hours of fasting. Milk led to the defaunation of a great proportion of the animals supplied all at once in an amount of 5-10% of rumen fluid volume. With cream the amount could be lower according to the higher fat content. Defaunation with concentrate was found to be not dangerous only for animals adapted to intensive feeding sufficiently. Additionally, a series of in vitro experiments were carried out to evaluate the reasons for the anti-protozoal effects of these methods. Concentrates rich in starch had toxic effects against protozoa, which mainly derived out of the depression in ruminal pH. The formed lactic acid had further effects irrespective of pH. The addition of crude fibre, especially of cellulose or lignin, reduced or prevented the anti-protozoal effects of concentrate fed ad lib. This was not so with the addition of buffers. With milk the included fat was shown to be responsible for the anti-protozoal effects, while the other main constituents of milk were of no importance.

Animal Feed↗
PubMed1986

[Allantoin excretion of wethers in variations of raw protein and energy administration].

216 values of urinary allantoin excretion were received from 8 digestibility trials, which included 48 rations with different protein and energy content. Thus relations between allantoin excretion and food intake and ration composition, respectively, could be evaluated. Additionally variations in N balance were measured, since there is a close relation to allantoin metabolism. Fecal N excretion was elevated with increasing energy intake, but varied only slightly with modified N supply. Urinary N excretion and also N retention increased with higher N intake. On the other hand urinary N losses were reduced with increasing energy supply and part of the saved nitrogen was deposed into the body. There was a distinct increase in allantoin excretion with raised protein intake, when N supply ranged generally low. But with a daily supply of crude protein above 60 to 70 g there was no significant further response in allantoin excretion. Allantoin excretion increased linearly with higher energy supply. Several restrictions for conclusions on the extent of microbial protein production in the digestive tract estimated out of measured allantoin values were discussed.

Allantoin↗
PubMed1985

[Effect of type of starch and quantity in rations on apparent and true digestibility of nitrogen and nitrogen balance in sheep].

In a digestibility trial 5 semisynthetic rations were fed in 3 periods to 10 male sheep to examine the effects on N balance, components of faecal nitrogen and N digestibility. The rations contained constant amounts of nitrogen but different contents of cellulose and two different types of starch (untreated and steamflaked). Content and type of starch did not show any noticeable effect neither on excretion of undigested dietary nitrogen nor on true digestibility. There could not be noticed any effects on the apparent N digestibility by changing contents of cellulose or untreated starch. If the rations contained steamflaked corn starch, the animals excreted more faecal nitrogen and therefore showed a lower apparent N digestibility. Especially the water soluble N fraction of the faecal nitrogen was clearly higher. Compensation took place through a lower N excretion with the urine. The reason for increased faecal N excretion may be higher microbial protein synthesis in the rumen. This was accented by the allantoin excretion with the urine.

Animal Feed↗
PubMedDate not supplied

Endogenous excretion and true absorption of cobalt as affected by the oral supply of cobalt.

At the end of a 49-d experiment with 32 growing male rats, a period of 8 d was used to determine endogenous excretion and true absorption as well as apparent absorption and retention of cobalt with the aid of the isotope dilution technique. For this purpose, a single im dose of 58Co was applied at d 35 of the experiment. After that, urine and feces were collected separately from d 8 to 15 after injection of the isotope. The specific cobalt activity of the liver was used as an endogenous reference source. The basal diet provided 5.9 ppb cobalt, the different treatment groups were obtained by supplementing the diet with 0, 10, 50, 250, or 1250 ppb cobalt. The different diets were offered from the beginning of the experiment. In the balance period, apparent and true absorption as well as fecal excretion behaved similar to cobalt intake, whereas urinary excretion increased more rapidly with increasing cobalt supply. Endogenous fecal excretion accounted for 3.5 ng Co/d in the groups fed the diets without and with 10 ppb cobalt. An increase was not observed until supplementing the diet with 50 ppb cobalt. This increase between 250 and 1250 ppb cobalt was higher than the corresponding increase in the dietary cobalt supply. This indicates that endogenous fecal excretion might be more important for homeostatic regulation at a higher dietary cobalt concentration. Endogenous renal excretion as calculated from the results of the isotope dilution technique showed a similar kind of response to increasing cobalt supply as endogenous fecal loss. Nevertheless, the elimination of excessive cobalt mainly took place by adjusting urinary excretion, whereas the variations in true absorption and endogenous fecal excretion had no quantitative importance. Apparent and true absorption were on average 28.0 and 29.8%, respectively, of the cobalt intake. In the case of retention, a marked decline was observed from 19% in the depletion group to 3% with 1250 ppb cobalt, again demonstrating the importance of urinary excretion for controlling the cobalt content of the organism.

Administration, Oral↗