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H Bergner

Publications and source records attributed to H Bergner.

At least 91 records · Page 5Linked to original sources
PubMed1978

Estimation of rate of protein synthesis by constant infusion of labelled amino acids in pigs.

1. The fractional synthetic rates of tissue proteins were studied in growing pigs using the constant-infusion technique of tracer-labelled amino acids ([14C]leucine and [14C]lysine) and the mathetmatical model for calculation, employed in rats by Garlick, Millward & James (1973). 2. During a 6 h infusion, samples were taken from blood and muscle and at the end of the infusion from liver, muscle, pancreas, heart, duodenum, jejunum, ileum, colon, and skin. The specific radioactivity of free and protein-bound leucine and lysine was estimated. 3. A quasi-steady-state in the specific radioactivity of free plasma leucine and lysine was reached within approximately 2 h, the rate-constants being 35 and 48/d respectively. 4. The specific radioactivity of free leucine and lysine in plasma was used to calculate the flux of these amino acids. It was found to be higher than the daily intake. 5. The average fractional rate of protein synthesis in muscle and heart 8.1% d, in small and large intestine the values were 50 and 33% d respectively and in liver and pancreas more than 100% d. 6. The calculation of protein synthetic rate in pig tissue using the constant-infusion method of labelled amino acids seems to be a suitable toof for study of this species.

Animals↗
PubMed1978

[Characterization of radioactivity distribution in the organism during constant intravenous infusion of tracer amino acids and calculation of the rate of tissue protein synthesis in rats].

Male wistar rats (100 g live mass) were given infusions into the tail vein of 14C-leucine and 14C-lysine simultaneously for 0.5; 1.0; 2.0; 3.0; 4.5; 6.0 and 7.0 hours. At the end of the infusion the specific radioactivity of the free leucine and lysine in the blood plasma, liver, M. gastrocnemius, small intestines and colon were ascertained as well as after the 6-and-7-hour infusion that of the protein-bound leucine and lysine. In all tested tissues the specific radioactivity of the free amino acids attained a plateau during the 6-and-7-hour infusion. The rate constants for the increase were calculated for each organ tested. The two amino acids used are suitable for the calculation of the fractional rate of protein synthesis in tissues. The values of the fractional rate of protein synthesis calculated on the basis of the 6-and-7-hour infusion were: 54 +/- 7.7%/day for the liver, 9.4 +/- 1.2%/day for muscles, 89 +/- 12.2%/day for the small intestines and 42 +/- 5.9%/day for the colon. The simultaneous application of two tracer amino acids is recommendable for the estimation of the precursor pool for protein synthesis and the more accurate calculation of the rate of protein synthesis.

Amino Acids↗
PubMed1978

[New method of checking the quality of food proteins required for maintenance. 2. 15N excretion in feces of test rats labelled with 15N after feeding with different protein sources].

For 7 days 37 test rats received a casein diet with an extra of 6.6 mg 15N-excess in the form of ammonium acetate. From the eighth test day onwards 4 resp. 5 rats each received various protein sources under maintenance conditions (115 kcal/kg body mass0,75). The atom-% 15N-excess was determined in feces, blood liver and muscles (urine cf. 1st information). The endogenous quota of N in the feces was calculated as follows: (formula: see text). The numerical value of the TCA-soluble fraction of N in the total blood was corrected by the decrease of the atom-%15N' in the last 12 hours (time for the passage of the fecel matter from small intestines to excretion). Since the endogenously excreted N-amount varied greatly according to different feed, a scale is proposed as biologic value of food proteins, which exclusively refers to the metabolic fecal nitrogen (MFN) under conditions of maintenance (abbr. MFN-BV). A proposal for its definition is: (formula: see text). Above that, a total BV is suggested which also refers to maintenance metabolism. The total BV is calculated as follows: (formula: see text). The following values were ascertained for MFN-BV and total BV: casein = 80 and 82; complete egg=68 and 67; fish meal=61 and 86; Torula yeast=31 and 46; peas=41 and 43; soya (assay protein)=73 and 61; wheat=47 and 71; gelatin=64 and 42. Finally, the recommendation is given to include in feed tables real digestibility values for food proteins ascertained with the 15N method. In the above mentioned order the following values of the real digestibility of proteins were ascertained with the 15N method and classical methods: casein=98.2 and 97.2; complete egg=100.0 and 98.7; fish meal=96.9 and 93.4; Torula yeast=83.0 and 67.6; peas=97.1 and 85.6; soya (assay protein)=98.3 and 96.4; wheat=95.7 and 87.3; gelatin=99.1 and 96.0. *cf. 1st information Bergner et al. (1978)

Animals↗
PubMed1978

[Metabolism-oriented lysine requirement of mature rats based on the catabolism rate for 14C- and 15N-labelled lysine].

Mature male albino rats (ca. 300 g body mass) received 10 diets with a varying lysine content (1.6 to 8.4 g/16 g N). In one partial test the animals were fed ad libitum and in another partial test they were kept in the state of maintenance by limiting the amount of the diet. After 7 feeding days the catabolisation of 14C-lysine into 14CO2 was measured and after 8 feeding days the 15N-excretion in urine after 15N-lysine doses was ascertained. Based on these characteristics typical of metabolism, which show increased catabolisation of the amino acid after the lysine requirement was met, the lysine requirement of a mature rat was determined as 3.5 to 4.0 g/16 g N in the diet. In conclusion, this shows that the lysine requirement in the state of maintenenace and of mature animals is considerably lower than during the period of growth.

Animals↗
PubMed1978

[The effect of types of rations on a straw basis on fermentation and volatile fatty acid production in the rumen of lactating cows. 2. Ruminal fermentation and milk yield criteria after use of a high-fiber straw pellet batch as a basic ration component].

Lactating Black-Pied (DSR) cows were used to study, over a period of 100 days, the influence of different basal ration types (experimental group - straw pellets; control group - dried forage + fodder root crops) on fermentation response and daily production rate of volatile fatty acids (VFA) as well as on some criteria of milk yield. Whilst only slight differences were found between the experimental groups in the molar proportions of VFA, the straw pellet-concentrate ration resulted in a lower VFA production as compared to the conventional ration. The control group's VFA production relativated to energy intake, was found to be of the same level (4.1, 4.3 and 3.9 Mol/1 kilo energetic feed equivalents/cattle) after 30, 60 and 100 days of feeding, respectively. The corresponding values in the experimental group declined from 3.3 to 2.3 and 1.9 Mol/1 kilo EF/cattle when feeding a high-fibre straw-pellet batch as basal ration component. The VFA production rates rather diverging between both groups were not found to have a uniform effect on the milk synthesis processes. Both the daily and the first 100-day milk yields did not differ between the groups but within the range of statistical error. Statistically secured positive correlations were found to exist between concentration and production of VFA which, however, depend on the basal ration type and revealed a relatively wide deviation.

Animal Feed↗
PubMed1978

[The influence of different straw-based ration type on fermentation and production of volatile fatty acids in the rumen of lactating cows. 3. Rumenal fermentation processes and milk yield criteria after using a low-fiber straw pellet batch as basal ration component and a fully pelleted straw-based ration].

Lactating Black-Pied (DSR) cows were used to study, over a period of 100 days, the influence of different basal ration types (I-treated wheat straw pellets, low-fibre; II- monodiet pellets containing 48% of wheat straw; III = conventional rations based on fresh forage and arable root crops) on the molar fermentation pattern and the daily rate of VFA production and some milk yield criteria. Ration types I and II results in almost equal fermentation patterns of the VFA; as against the conventional ration types (III) a significantly higher molar acetate propertion as well as a highly significantly decreased molar proportion of iso-acids were found. The daily rated of VFA production relativated to energy intake were as follows (in the order of the ration types mentioned): 4.9, 4.2 and 5.0, and 3.3, 2.5 and 3.3 moles per 1,000 anergetic feed equivalents (cattle) after 30 and 100 days of feeding, respectively. In both trials, only about 80% of the relative VFA production of the straw pellet-concentrate (I) and conventional (III) ration types were found when feeding fully pelleted diets (II). On account of the relatively wide variation of the experimental results no statistically secured findings were obtained as to the milk yield criteria, but ration type II produced some 200 and 300 kg milk less thant ration types I and III, respectively, during the 100-day experimental period.

Animal Feed↗
PubMed1978

[A new method for testing the quality of food protein for maintenance metabolism. 1. Investigations into the amount of 15N excreted via the urine of 15N-labelled young rats fed various proteins].

Over a period of 7 days, 38 experimental rats were fed a casein diet with a supplementation of 6.6 mg 15N-excess (15N') in the form of ammonium acetate. From the 5th experimental day, groups of 4 or 5 rats each were fed, over 5 days, different protein carriers to meet the meintenance requirement (115 kcal/kg body weight 0.75). The 15N-excretion via the urine, in terms of % of N absorbed from the food protein, served as yardstick of protein quality under maintenance conditions. The least 15N-excretion rates were reciprocally relativated for this maximum value (reciprocal 15N excretion biological value). The least 15N-excretion values from the 2nd to the 5th experimental days allowed to establish the following order for protein quality under maintenance conditions: fish meal, casein, wheat, whole egg, soybean (assayprotein), yeast peas, gelatin. The very good quality of the wheat protein for the maintenance state is seen in relation with the high content of glutamic acid (33.5 g/16 g N) and aspartic acid (5.7 g/16 gN). The found lysine content of the wheat protein (3.1 g/16 g N) proved sufficient for maintenance conditions.

Animals↗
PubMed1978

[Results of comparative studies on ammoniated straw pellets conducted in two research institutions of animal nutrition].

Ammoniated straw pellets were produced from pure wheat straw in a pelleting press reaching temperatures of more than 90 degrees C, 4% NH4HCO3 being added as degradation agent. Digestibility trials with sheep gave 389 energetic feed equivalents (cattle) per kg straw dry matter. This value exactly agrees with the formula Energetic feed equivalents (cattle)/kg DM = 650 -6x x = % crude fibre in dry matter which had been reported first in 1973 by Bergner and Marienburg (Arch. Tierernährung 23, 423 [193]) for chemically treated straw pellets. When testing the digestibility of the same straw pellets charge in the Animal Nutrition Division of the Dummerstorf-Rostock Research Centre for Livestock Production, considerably lower values were found which would allow to calculate energy concentration to amount to 310 energetic feed equivalents (cattle)/kg DM (see Arch. Tierernährung Vol. 28, page 393). The reason for this 20% lower feed value of the straws pellets lies possibly in the reversibility of the degradation effect when using ammoniacal media. The digestibility of the straw pellets had been tested in the Berlin research Institution one year earlier than at the Rostock Institute. The possible causes of the reversibility of the ammoniacal degradation effect are discussed.

Ammonia↗
PubMed1978

[Determination of lysine requirement in growing rats as based on the catabolism rate of 14-C- and 15-N-labeled lysine].

Male Wistar rats (weighing some 80 g at the start of the experiment) were fed diets containing maize gluten as protein carrier and which was supplemented with amino acids (except lysine) in such way that their concentrations came up to the requirement norms. Lysine was gradually supplemented this resulting in 10 diets of different lysine content (1.6-10.6 g lysine/16 g N). On the 7th experimental day, 4 animals of each group were labelled with 14C-lysine and subjected to 2-hour measuring of 14CO2-excretion. On the following day, the animals were injected i.p. 15N-lysine, the urine being collected over 24 hours to determine 15N-frequency in urine. Both 14CO2-excretion and 15N-frequency in urine were found to remain constant at a lysine content of the diet up to 4.5 g/16 g N and rose steeply from 5.8 g lysine/16 N on. Under the experimental conditions chosen the lysine requirement is deduced to be 5 g/16 g N. This method of lysine requirement determination is highly sensitive and exact because it covers the catabolization of the amino acids under study and not so parameters that are known to be influenced by other factors such as growth, N-balance, total N-conversion or CO2-formation. The method can also be applied to metabolic situations not connected with productive performances.

Animal Nutritional Physiological Phenomena↗
PubMed1978

[Dynamics of 15N-isobutylidene diurea (IBDU) in sheep. 1. IBDU conversion in the digestive tract].

Four Merino Landrace wethers averaging 47.6 kg body weight were adapted to a semi-synthetic diet containing as the only N-source 60 g of IBDU per day. After the adaptation phase, on the 1 st experimental day the IBDU of the morning feed was given in 15N-labelled form (701 mg 15N-excess). After 2 1/2, 7 1/4, 12 and 24 hours the experimental animals were killed without having been fed again. The comparison of the IBDU-concentrations in the content of the rumen bottom with the residual rumen content did not allow to draw conclusions regarding IBDU-sedimentation at the bottom of the rumen. For the 15N-decline in the rumen content, a relationship was established following y = 76.3 - 2.62 (r = 0.96) (see fig. 2). In the order of killing times the following 15N-IBDU amounts were retrieved (% of intake): I = 15.6%, II = 24.1%, III = 3.3% and IV = 3.6%. 7 1/4 hours after starting the experiment, 40% of the 15N-labelled material were found in the rumen in the form IBDU; after 12 hours it came to 10%. Except for sheep I, 15N-urea was not found but in small amounts. Only sheep I and III revealed IBDU-traces in the abomasum, but in the small intestine of all sheep 2 to 6% of the amount taken in. This fact is explained with the endogenous influx of IBDU from the blood. An additional experimental sheep provided with a ligature at the abomasum entry, revealed that IBDU is absorbed from the rumen and allowed to enter the individual segments of the intestine in small amounts.

Animals↗
PubMed1977

[Isobutylidene diurea, a new NPN source for ruminants. 3. Excretion of isobutylidene diurea following feeding of N-15 isobutylidene diurea to lactating cows].

2 experimental cows received isobutylidenedi urea added to a natural diet in amounts of 175 g (I) and 730 g (II) per day for a period of several weeks before the trial was started. On the 1st day of experiment the morning dose was labelled with 5.05 g of excess 15N. 8 hrs after the beginning of the trial of 15N level in the TCE soluble portion of blood plasma (TCE=trichloroacetic acid) increased and remained at an elevated level until the 36th hour of experiment. Similarly, the values for maximum urinary 15N concentrations were maintained for a prolonged period of time. Isobutylidenedi urea was excreted with the urine in rates related to its solubility. Only small percentages of the 15N intake were excreted in the TCE soluble portion of the milk (cow I: 0.03%; cow II: 0.05%). The 15N-labelling of milk protein provides evidence for the fact that nitrogen from IBDU is utilized for the synthesis of milk in the cows. The amount of urea in milk averaged 400 mg per litre. None of the milk samples tested contained IBDU.

Animal Feed↗
PubMed1977

[Secretion of radioactively labeled amino acids into the digestive tract. 2. 14C labeling and amount of 14C leucine in the intestinal contents after subcutaneous injection of 14C leucine in rats].

Experimental rats received a subcutaneous injection of 14C of varying activity. The rats were then killed in groups within a period of from 2 mins to 30 mins after the injection. A certain amount of 14C activity was detected in the intestinal contents as early as 2 mins after the injection, both as free 14C leucine and in the TCE soluble portion of the intestinal contents (TCE=trichloroacetic acid). A comparison of the degree of labelling in the TCE soluble and the TCE precipitable fractions of the intestinal contents showed that the most likely way for free 14C leucine to get into the lumen of the intestine is via the pancreatic juice while that for protein-bound 14C leucine is through the proteins in the pancreatic gland. The degree of labelling in both fractions decreased very steeply from the first to the third third of the intestine. This may be caused either by absorption of the secreted 14C leucine or may be brought about by a delay in food passage through the intestine.

Amino Acids↗
PubMed1977

[In-vitro studies on the catabolism of acetyl urea in liver tissue].

In vitro-studies were carried out with hepatic tissue from freshley slaughtered cows using 14C acetyl urea (in which the urea-C-atom was labelled). Methods of thin-layer chromatography were used to investigate the process of acetyl urea degradation. The cows had not previouslybeen adapted to acetyl urea. The test mixtures used contained 3.3 mg or 20 mg acetyl urea per 100 ml of the homogenate. The pattern of acetyl urea degradation in these mixtures was investigated after 1 min, 3 mins, 10 mins and 30 mins. The degradation rates were found to be the same for both types of test mixtures. This indicated that a saturation of the substrate had not been accomplished, even when higher concentrations of acetyl urea were used. Supplementary addition of urease to the test mixture for decomposing the quantity of urea always produced did not alter the rates of acetyl urea degradation. From this it may be concluded that even under in vivo-conditions some urea will be liberated when acetyl urea passes through the liver.

Animals↗
PubMed1977

[Studies on the methionine-threonine imbalance in chicks].

Experimental lots of 12 chicks each received, in addition to their standard diets, supplements of 1, 2 or 3% DL-threonine, in each threonine treatment 1, 2 or 3% methionine being added. After an 8-day feeding period the chicks were injected 35S-methionine and were killed after 6, 12 and 24 hours, respectively. The increasing methionine supplementation was found to markedly deteriorate chick growth. It was not possible to correct this effect by any of the threonine doses. The 35S-activity of the blood decreased very strongly from the 6th to the 12th hours following injection. The 35S-activity of the liver also declined clearly at low threonine supply, but less markedly at high threonine rates. In the breast muscle, the 35S-activity also proved three times higher 24 hours after the injection at equal methionine supplementation to the diet (1 or 2%) and at triplicated threonine level (3% against 1%). This finding is related with the fact that threonine supplements to not attenuate the negative imbalance symptoms after methionine overdosing, but that they are likely to aggrevate due to transport competition. The possibility of threonine degradation into glycine does not seem to be of importance for methionine detoxication in chicks.

Administration, Oral↗
PubMed1977

[The secretion of radioactively labeled amino acids into the digestive tract. 3. 14C-labeling of the intestinal wall after subcutaneous injection of 14C-L-leucine in rats].

Experimental rats allotted in 4 different groups received 14C leucine injections at 4 different levels of specific 14C activity. Groups A and B were injected a leucine dosis corresponding to the daily requirement, the specific 14C activity being high (A) and low (B). Groups C and D were injected a leucine dosis of one ninth the amount applied to groups A and B, the level of 14C labelling being again high (C) and low (D). The 14C labelling of the TCE-soluble fraction of the 1st third section of the small intestinal wall in all 4 groups proved identical with the course of the curve representing the TCE-soluble fraction of the small intestine contents. The specific 14C leucine activity of the intestinal wall of the 1st third section of the small intestine was found to be 5 to 8 times lower than in the TCE-soluble fraction of the pancreatic gland. Thus a dilution effect has been produced from absorption. Two minutes after injection, the 14C labelling of the intestinal wall proteins had half the level of labelling of the pancreatic proteins. This finding applied to both the 1st and the 3rd sections of the small intestine. The results obtained allow to conclude that 14C labelling of intestinal wall proteins is relatively independent of 14C leucine absorption and is conditioned by the level of labelling of the plasma leucine.

Animals↗
PubMed1977

[Metabolism-oriented determination of amino-acid requirement by means of catabolic rates of 14C- and 15N-labelled lysine under maintenance].

Male Wistar rats (of 60 g live weight) allotted in 10 groups were fed diets with gradually increasing lysine levels ranging from 1.4 to 7.4 g lysine/16 g N. Feed intake was restricted so much that the experimental animals did not change their live weights during the last 3 days of the 8-day experiment period. On the 7th experimental day, 4 animals of each group were injected i.p. 14-C-L-lysine, the 14CO2-excretion being subsequently measured over a period of 2 hours. On the next day, 6 animals of each group were applied an i.p. injected of 15N-L-lysine, the urine being collected over the following 24-hour period to measure the 15N-frequency. Applying both labelling methods, an increased catabolisation of the amino acid was observed after the metabolically necessary lysine requirement had been covered. The methods are very sensitive and revealed, under the experimental conditions chosed, a lysine requirement coverage of about 3 g lysine/16 g N. The possibility of using also 15N-labelled compounds in the metabolism-oriented amino acid requirement determination is likely to facilitate the transfer of the methodology to farm animals and would thus allow to study the amino acid requirement of man. The metabolism-oriented amino acid requirement determination will likewise allow to estimate exact amino acid requirement data under conditions that cannot be rated on the basis of productive yields.

Amino Acids↗