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Biomedical subjects

H Bergner

Publications and source records attributed to H Bergner.

At least 73 records · Page 4Linked to original sources
PubMed1983

[Changes in protein synthesis in the liver and small intestine of rats after feeding].

Rats trained on fast food intake received a combined intravenous injection of [14C]valine and unlabelled valine before and 1, 2, 4 and 6 h after food intake, respectively. The rate of protein synthesis was calculated basing on the average specific radioactivity of free valine in blood plasma and in the analyzed tissues during the 10 min incorporations period and on the specific radioactivity of protein bound valine in the tissues at the end of incorporation time. Before food intake the fractional rate of protein synthesis (ks) in liver was 55-67% per day and increased 1 to 4 h after food ingestion to 80-120% per day. ks in small intestine before food intake amounted to 78-109% per day and no specific changes were observed in time course. The synthesized amount of protein in liver and small intestine (related to 100 g body weight) was found to be 14-19 mg/h before food ingestion. This value increased postprandially in the liver to 25-32 mg/h and decreased towards the end of the testing period to 20-25 mg/h. The stimulation of the rate of protein synthesis in liver and perhaps in other organs may be part of a mechanism delaying the inflow of amino acids into tissues with lower turnover rates.

Animals↗
PubMed1982

Studies on the range of tissue protein synthesis in pigs: the effect of thyroid hormones.

The effects of thyroid hormones on the range of tissue protein synthesis in growing pigs using the constant infusion technique with [14C]lysine were studied. 2. During a 6 h infusion, samples were taken from blood and, at the end of the infusion, from liver, pancreas, stomach, small and large intestines, kidney cortex, kidney medulla, muscle and skin. 3. Lower relative specific radioactivities of free leucine and lysine in several tissues were observed in the hormone-treated group than in the untreated one. 4. The range of protein synthesis rate and the daily amount of protein synthesized in tissues was higher in all tissues after application of thyroid hormones. 5. Assuming that the organs analysed represented 70% of the total trichloroacetic acid-precipitable protein of the pig, the estimated range of daily protein synthesis was 251-490 and 312-880 g in untreated and hormone-treated pigs respectively.

Animals↗
PubMed1982

[Examination of protein digestibility in individual intestinal segments under in vivo conditions in experimental rats by the isotope dilution method].

Test rats were labelled with 15N over a period of 7 days and killed on the 12th day. 220 min. before they were killed the diet was changed (wheat diet leads to whole egg diet) and they were given a 14C-leucine injection. The 15N-labelling of the digesta proved to be suitable for the determination of the digestibility of the feed proteins in the individual sections of the intestines. If the atom-% 15N-excess of the TCA-soluble fraction of the digesta is = 100%, the resulting digestibility of the protein fraction (TCA-precipitable fraction) corresponds to the 15N-dilution of the unlabelled feed protein. The following digestibility values were ascertained: (formula; see text) The calculation method suggested here cannot be applied to the large intestine because microbial activity influences the quotients. 14C-labelling was also insufficient for gathering statements on the digestibility of proteins.

Animals↗
PubMed1982

Investigations on the amino acid secretion and absorption in the stomach of the growing pig.

Two pigs of 35 kg live weight were fitted with re-entrant duodenal cannulas anterior to the pancreatic duct and fed barley-soya or casein-wheat starch diets prior to the experiment. After 24 hours fasting they were given a single meal of 15N-labelled free amino acids-wheat starch (A) or 15N-labelled wheat (B) diets and digesta leaving the stomach was collected during 12 hours. The proportion of TCA soluble N in total N of digesta increased with time from 10 to 40% with diet B and decreased from 90 to 47% with diet A. Total N leaving the stomach within 12 hours accounted for 96% and 106% of N ingested on diet A and B, while the amount of 15N accounted for only 66 and 86% of 15N given in diets A and B, respectively. The content of endogenous N in the digesta was 1.22 g/12 h after feeding diet A and 1.67 g/12 h after feeding diet B. It was concluded that considerable amounts of N are secreted and absorbed in the part of the digestive tract proximal to the opening of the pancreatic duct.

Absorption↗
PubMed1982

Flow of endogenous and exogenous amino acids along the gut of pigs.

Digesta were collected from 5 pigs of 33 kg live weight fitted with re-entrant cannulas in the duodenum (within 20-30 cm of the pylorus) and terminal ileum. The pigs received a diet of barley, soya bean oilmeal and a vitamin and mineral mixture. The flow rates of digesta, total nitrogen and the individual amino acids were measured at different time after feeding and during two 24 h periods. A marked increase in the flow of digesta, nitrogen and amino acids was seen in the duodenum after feeding. Total flow during 24 h of nitrogen and amino acids except His, Val, Leu, Phe and Met exceeded intake. Output of nitrogen and amino acids from the duodenal cannula was 117 and 108% of intake, respectively. A method to calculate the ratio of endogenous amino acids in digesta based on the amino acid composition of digesta, diet and endogenous secretions was developed. The calculated amounts of endogenous amino acids passing the proximal duodenum and terminal ileum were 32.2 and 21.9 g per 24 h, respectively. The greatest amount of endogenous amino acids passed through the duodenal cannula in the first two hours after feeding (2-3 g/h) and then gradually decreased to 1 g per hour. The results are discussed in relation to other studies on the secretion of endogenous protein and its amino acid composition.

Amino Acids↗
PubMed1981

[Isobutylidene diurea as an NPN source for ruminants. 1. Rumen fermentation, digestibility of the nutrients and microbial protein synthesis in dairy cows].

In 3 experiments 2 lactating dairy cows received a mixed ration consisting of 10 kg maize silage, 2.5 kg hay, 2.0 kg barley, 1 kg dried sugar-beet pulp, 1.5 kg maize starch, 0.5 kg sugar, 0.2 kg of a mineral-vitamin mixture and 0.08 kg non-protein nitrogen (NPN) per animal and day. The ration contained 8.3 kg dry matter, 5.1 kEFU cattle and 1.18 kg crude protein, 0.5 kg of which from NPN, and was given in equal shares twice a day. Urea (I) or isobutylidene diurea (IBDU), to which the animals were not adapted (II) resp. adapted (III), were the sources of NPN.IBDU proved to a be a very slow source of NH3 in the rumen. 2 hours after the intake of NPN 48 . . . 75, 5 . . . 9 and 5 . . . 12 mg NH3/100 ml could be detected from I to III. Up to the third hour the concentration of IBDU and urea increased in III, which is due to the slow distribution of the slowly soluble IBDU in the fluid digestaphasis. 12 hours after the feeding the level of IBDU and urea in III still amounted to 25 mg urea/100 ml, in I to 1 mg/100 ml only. In the first 3 hours after supplying the NPN the pH-value of I was more than 1 unit higher than that of II and III. There were no significant differences in the fermentation models between the variants, the concentration of volatile fatty acids was 12.6, 12.3 and 11.1 mmol/100 ml. In the stomachs the digestibility of the organic matter was 52, 51 and 54%, that of the crude cellulose 64, 62 and 66% and that of the starch 91, 93 and 98%. At the duodenum the passage rate of N was 87 . . . 93, 107 . . . 126 and 96 . . . 130% of the N-intake, that of NH3-N 6, 43 and 22 g per day and that of bacteria-N 61 . . . 76, 78 . . . 100 and 76 . . . 96% of the N-intake. 2.3 . . . 2.8, 2.6 . . . 3.2 and 2.1 . . . 3.1 g bacteria-N were formed per 100 g dry matter fermented in the rumen. In the intestines 55 . . . 61, 57 . . . 64 and 48 . . . 71% of the feed-N were available as non-NH3-N. The conclusion is that in comparison to urea and concerning IBDU, the rumeno-hepatic circulation plays a definitely bigger role for the N-supply of the rumen microbes and that the possibility of the better N-utilisation can be derived from that.

Animals↗
PubMed1981

[A new method for testing the quality of food proteins for maintenance metabolism. 4. Testing of isolated proteins as well as various protein sources of plant and animal origin].

Male adult rats (370 g body weight) were fed on maintenance level (460 kJ ME/kg 0,75). In a 10 days preliminary period they received a casein/methionin diet (95,5 W/W) supplemented with 10 mg N-15-excess per 0,178 kg metabolic body weight in form of ammonium acetate. Thereafter the animals were changed on 8 isonitrogenous diets containing as protein sources casein, soya protein, gelatine, whole egg, fish meal, pea, wheat and yeast. The N-15-excretion via urine and faeces 6th and 10th day after the end of labelling period was used to evaluate the dietary proteins for maintenance. N-15 in urine was lowest in animals fed with the wheat diet and highest after feeding the whole egg diet. From these data a so called "N-15-excretions BV" was calculated, which indicated the highest quality for wheat and soy protein in meeting the needs of the intermediary metabolism in maintenance. On the other hand, dietary protein sources influence the loss of endogenous nitrogen as metabolic faecal nitrogen (MFN). It was found to be lowest in animals fed with diets containing isolated proteins (6 mg MFN/100 g body weight) and highest after feeding protein sources of plant origin with a high content in crude fibre (10 mg MFN/100 g). Both, losses of N-15 via urine and via feces were combined in a parameter called "total BV". According to this parameter the differences in quality for maintenance were only little between the protein sources testet (casein 100, soy protein 100, pea 99, wheat 99, whole egg 92, fish meal 89, gelatin 89). It was concluded that in maintenance the supply with indispensable amino acids is not critical and that the supply with dispensable amino acids (or nonspecific nitrogen) is of great importance.

Amino Acids↗
PubMed1981

[Isobutylidene urea as NPN source for ruminants. 2. Digestion of 15N-labeled isobutylidene urea in lactating dairy cows].

Two cows with rumen cannulae and duodenal re-entrance cannulae received in the first experiment (Ia and IIa) a conventional diet on the basis of a mixture of maize silage, hay and concentrated feed and after a three-week adaptation to isobutylidene diurea (IBDU)--276 g per animal and day--138 g IBDU with 3.865 mg 15N-excess as a single supplementation to their first meal. In the second experiment (IIa and IIb) after a 6-week break the same cows served a repeated experiment without IBDU adaptation. Irrespective of the adaptation, a re-increase of the 15N-labelling in the TCA-soluble N in the rumen could be proved between the 6th and the 8th hour after the intake of the isotopes, which resulted from the backflow of 15N to the rumen. In the duodenal digesta the maximum labelling of the TCA--soluble N-fraction appeared 12 hours after the intake of the isotopes. At that moment a labelling plateau began in the protein fraction, which lasted to the 36th hour. On an average of all 4 cows approximately 30% of the 15N taken in the TCA-precipitable fraction and 55 and 60% in the TCA-soluble fraction had passed the duodenum up to the 72nd hour after the beginning of the experiment. Up to the 72nd hour after the beginning of the experiment, approximately 15% were excreted in urine, approximately 16% in feces and approximately 7% in the milk. This shows that roughly one half of the 90% 15N-amount measured at its passage in the re-entrance cannula (related to the intake) was metabolised in the rumen at least twice, resp. after the first passage through the duodenum it originated from the intermediary metabolism (e.g. as amino acids and their incorporation as digestion secretions). Negative correlations could be ascertained between the pH-value of the rumen fluid and the 15N incorporation in the rumen proteins as well as 15N-excretion through the TCA-soluble and -precipitable quota of feces. An adaptation to IBDU is obviously not necessary.

Animal Feed↗
PubMed1981

[Absorption of 14C-leucine and 15N-leucine in rats after feeding a fish meal diet in comparison with a gelatin diet].

Albino rats received after nine days of adaptation to a fish meal diet in comparison with a gelatin diet 14C-U-Leucine and 15N-L-leucine via a pellet made from the specific diet after food deprivation for 15 h. Thereafter, the experimental animals consumed the non-labelled experimental diet ad libitum. Five times after the pellet intake, 30 min, and 1, 2, 4 and 6 h after injection of the labelled food, four experimental rats were sacrificed. The contents of the digestive tract and tissue samples were examined for 14C and 15N. We detected to following percentages of 14C-intake or the intake of 15N-excess (15N') in the TCA-soluble fraction of the gastric contents: [Formula: see text] We found in the TCA-soluble fraction of digesta of small intestine the following percentage of intake: [Formula see text] Where these values regarded as non-absorbed leucine, the 14C values obtained up to four hour period of experiment would be too high. Presumably, they are in the case of both diets simulated by other 14C-metabolites which originate from the leucine catabolism and reach the intestinal lumen. Amino acids labelled with 15N should be preferred in studies on the absorption of amino acids because, in case of catabolism, the 15N-aminogroup is excreted mainly in the form of urea via urine.

Animal Feed↗
PubMed1981

[A new method for testing the quality of food proteins for maintenance metabolism. 3. Methodological studies of 15N-labeled adult rats].

Experiments were made in order to estimate the optimum amount of daily N-15-application and the optimum period for labelling adult rats in maintenance conditions with N-15-ammonium acetate. Labelling periods of 7 and 10 days were combined with 10 or 30 mg N-15-excess per day and 0,178 kg0,75. N-15-label in urine growth to a plateau within 3--4 days during N-15-feeding. After omitting N-15 from the diet the N-15-label declined rapidly and reached again a relative stable value within 3 to 4 days. The curve pattern for N-15-label in faeces was similar, however, with a time lag of about 24 hours. The ratio between N-15-label in faeces was similar, however, with a time lag of about 24 hours. The ratio between N-15-label in urine and faeces was constant from the 6th to 10th day after the labelling period. Therefore, this period should be used for the estimation of metabolic faecal nitrogen on the basis of N-15-label of nitrogen in faeces and N-15-label of endogenous nitrogen secreted into the gastrointestinal tract. Both, N-15-label of urine and N-15-label of TCA-soluble fraction of plasma can be used as a indicator of the N-15-label of endogenous faecal nitrogen. But, from methodical point of view urine seems to be more convenient. Among the variants of labelling tested the best was found to be a 10 days period with 10 mg N'--15/0,178 kg0,75 daily.

Acetates↗
PubMed1981

Effect of thyroid hormones on the in vivo protein synthesis in rats.

The studies were made in order to estimate the rate of tissue protein synthesis in euthyroid, hyperthyroid and hypothyroid rats (110 g body weight). Hyperthyroidism was simulated by daily oral application of 4,44 micrograms thyroxine (T4) and 0,89 micrograms triiodothyronine (T3)/100 g body weight. Hypothyroidism was induced by oral application of 17,8 mg of methylthiouracil (MTU) per day and 100 g body weight. In both cases the treatment lasted for 7 days. The concentration of both hormones in blood serum was twice that of the control group in the T3 + T4 treated group. The MTU application produced a decrease in T3 and T4 concentration to levels below the lower detection limits of the methods used. The fractional rate of tissue protein synthesis was estimated using the constant intravenous infusion technique with L-14C-leucine and L-14C-lysine simultaneously. The range of the fractional rate of protein synthesis was found to be higher in hyperthyroid than in control animals in all organs under study (liver, small intestine, large intestine, gastrocnemius muscle and pancreas). Protein synthesis was stimulated to the greatest extent in muscle (4,5--5,1% . d-1 in controls vs, 5,5--6,7% . d-1 in hyperthyroid animals). The influence of hypothyroidism on the rate of protein synthesis was uncertain.

Animals↗
PubMed1980

[Investigation of the feed value of straw].

Two groups of four pigs each were fed ad libitum with rations containing 70.7% barley, 7.7% fish meal, 0.7% Sussopan, 0.9% mixed minerals and 20% straw meal. Group 1 received partly hydrolysed straw meal, group 2 untreated straw meal. When those rations were given, weight increase performances of 767 g per animal and day in group 1 and 537 g per animal and day in group 2 were achieved in a preliminary 30-day feeding period. On the basis ofthe weight of the feed remnants, a consumption of 19.7% dry matter of the straw meal (group 1) resp. 18,5% (group 2) of the total intake of dry matter could be ascertained. At an average live weight of 93 kg (group 1) resp. 87.5 kg (group 2) the digestibility of both rations was examined. A significant difference was only found for the crude protein fraction with an apparent digestibility of 74.6% in group 1 and of 79.1% in group 2. Those pigs which received partly hydrolysed straw meal consumed 71.4 g N per animal and day, of which 25,4% were excreted in feces and 32.4% in urine. Those animals which were fed with untreated straw meal consumed 62.9 g N per animals and day of which 20.8% were excreted in feces and 49.7% in urine. The higher N-excretion in feces could also be proved for most amino acids the feeding with partly hydrolysed straw meal. For arginine, serine, glutamic acid, proline, isoleucine and Leucine these differences were significant. Differences concerning N-retention could not be found between the groups. 25% of the organic matter of the partly hydrolysed straw meal, 9.4% of the crude fibre and 44.2% of the N-free extractives were digestible. Of the untreated straw, 12.9% of the organic matter, 5.5% ofthe crude fibres and 21.7% of the N-free extractives were digestible. 193 EFpig were calculated for partly hydrolysed and 105 EFpig for untreated straw meal per kg dry matter. The result of substracting the CaCl2 of the partly hydrolysed straw meal is 205 EFpig per kg dry matter of the straw.

Animal Feed↗
PubMed1979

[Feed value of straw materials in the in vitro system. 4. Influence of the additional pre-incubation with the rumen fluid of animals deprived of food on the in vitro rate of protein synthesis].

Rumen fluid was extracted from sheep after they had been deprived of food for 48 hours. This rumen fluid was either directly applied in an artificial rumen or after pre-incubation (up to 16 hours). The 35S-incorporation rate into the microbial protein was measured after the admixture of untreated straw meal, straw meal treated with NH3-water of with NaOH. Generally, the 35S-incorporation rates were highest for the blank experiments. The reason for this is that the straw meal admixtures withdraw from the microorganisms low-molecular, energetically utilisable substrates by absorption and adsorption. Pre-incubation could not much reduce the relatively higher 35S-incorporation rate of the blank experiments. The two treated straw variants were significantly superior to the untreated straw meal concerning the 35S-incorporation rate.

Animal Feed↗
PubMed1979

[Action of proteinase inhibitors in rats. 3. Influence of leupeptin on the rate of protein synthesis and the intracellular protein degradation by use of a test system including constant infusion of labelled amino acids, estimation of 3-methyl-histidine excretion and a triple-labelling technique].

Male Wistar rats (initial body weight 90 g) were fed ad libitum a whole-egg diet containing 10,5% crude protein. The animals of the experimental group received in each case of 1 mg leupeptin per 100 g of body weight in 12 hrs-intervals by i. p.-injection (3 days of treatment). Control animals got a leupeptin free solution. In addition, lysine dihydrochloride-alpha-15N was applied during the first three days of experiment to all animals and the nitrogen balance was determined. Urine from the N-Balance collection was analysed for 3-methyl-histidine excretion in order to calculate the degradation rate of myofibrillar proteins. On the fourth day the fractional rate of protein synthesis in several organs was estimated using the continuous infusion technique with 14C-leucine and 14C-lysine. The apparent biological half-lives of tissue protein were determined by a triple labelling technique, with (14C)-guanidino-L-arginine, L-5-3H-arginine and 15N-Lysine. The short-term treatment 3 days) with leupeptin did not affect the weight gain, the apparent digestibility of nitrogen and the N-balance. The fractional rate of protein synthesis was highest in the small intestine followed by the large intestine, liver and skeletal muscle and no influence of leupeptin treatment was observed. Furthermore no differences in the degradation rates of myofibrillar proteins between treated and untreated animals were found. The 3-methyl-histidine excretion via urine was 1.44 mg . kg-1 day-1 in both groups corresponding to a fractional rate of degradation of myofibrillar proteins of 2,5% per day. Apparent half-lives of tissue proteins in the small intestine, large intestine and liver, respectively, were shortest when estimated from the decay curves for the 14C-label and longest from the curves for the 15N-label. Leupeptin treatment resulted in prolonged apparent half-lives of the proteins in the large intestine and of the slowly turning over proteins in the liver. However, this effect seems to be caused rather by an increased reutilization of labelled amino acids than by a decreased protein degradation. Before continuing this kind of work the rate of uptake of injected leupeptine into tissues has to be investigated. Studies dealing with the in vivo action of proteinase inhibitors on protein metabolism have to include estimations of N-balance, protein synthesis rate, intracellular degradation rate of proteins as well as amino acid reutilization.

Amino Acids↗
PubMed1979

[Food value of straw meal in the nutrition of pigs. 1. Digestibility of the nutrients and N-balance after feeding with partially hydrolized straw meal].

Straw Meal was mixed with concentrated HCl at a mass proportion of approximately 10 : 1. After a one-hour duration of action the mixture was diluted with water (in proporation to the added HCl volume the double amount of water) and steamed in an electric steaming caldron for one hour. The partially hydrolised final product was neutralised with calcium hydroxide (3,5 kg per 10 kg HCl). In a digestibility experiment 4 pigs were fed according to the differential method with barley (supplemented with lysine and methionine) without straw meal resp. with straw meal (717 g barley dry matter+386 g straw meal dry matter per animal and day for pigs with an average live weight of 64.3 kg). In this test 21.0% of the organic matter of partially hydrolised straw meal, 0.5% of the crude fibre and 42.3% of the N-free extractives were digestible. When the animals were fed with barley exclusively (1045 g dry matter per day and animal of an average body weight of 61,4 kg), 17,1% of the 26,0 t N per animal and day were excreted in feces. After the feeding with straw meal admixtures, 34,5% of the 20,9 g N per animal and day were excreted in feces. When the feed consisted of 1,99 kg barley, 220 g fish meal and 565 g straw meal (dry matter in each case) per animal and day for the same pigs with an average body weight of 97,1 kg a digestibility of the organic matter of the partially hydrolised straw meal of 24,6% was achieved. 24.3% of the nitrogen consumed (72.9 g) by each animal per day were excreted in feces. After slaughtering, the pH-value in the caecum sould be ascertained as 6.0 to 6.5. The conclusion of this is that partially hydrolised straw meal contains approximately 20% utilisable carbohydrates and has a positive dietic effect in the digestive tract.

Animal Feed↗