[Endogenous nitrogen metabolism in 15N-labeled swine. 3. Endogenous excretion of 15N- and 14C-labeled secretions following a 14C-leucine injection]. / Untersuchungen zu endogenen N-Umsatzprozessen an 15N-markierten Schweinen. 3. Mitteilung. Endogene Ausscheidung von 15N- und 14C-markierten Sekreten nach einer 14C-Leuzininjektion.

Four pigs (59-65 kg live weight) were labelled over a period of 10 days with 15N in the feeding of a fishmeal diet (1), a fishmeal diet + partly hydrolysed straw meal (2), a horse bean diet (3) and a horse bean diet + partly hydrolysed straw meal (4). After a 24-hour fasting the animals were provided with simple cannulae in the upper part of the small intestines. After a fasting period of 24 h all four pigs received a 14C-leucine injection and the cannula secretion was collected in the subsequent 24 h. After the feeding of the diets without straw meal supplement (1 and 3) there were distinct differences in the secretion in comparison with the feeding with straw meal supplements (2 and 4) despite the long fasting period (48-72 h). 14C-activity could already be detected in the TCA-precipitable fraction of the secretion after 3-6 min of the injection in 1 and 3 but only 20 to 25 min after the 14C-leucine injection in 2 and 4. The specific 14C-leucine activity of the TCA-soluble fraction of the secretion was, after the straw meal supplementation to the fish meal diet, 15 times higher 25 min after the 14C-leu-injection, 25 times higher after 70 min, 36 times after 2 h and 1.8 times after 4 h than without straw meal supplementation. For all four diets a specific correlation (r = 0.96) could be ascertained between the increase of 14C-activity/mg N in the TCA-soluble fraction and the increasing crude fibre content in the diet between 25 and 180 min after the injection. Furthermore, a distinctly decreased N-secretion/h could be ascertained (correlation coefficient r = 0.84) with the increasing crude fibre content in the diet. The influence of the crude fibre on the parameters mentioned is seen in the changed osmotic conditions in the secretion, which may be caused by the changed regulation by hormones of the gastro-intestinal tract. The atom-% 15N' in both TCA-fractions of the secretion underwent big rhythmic variations, which is explained by different ratios of the components pancreatic juice, bile, and intestinal juice.

[Endogenous nitrogen metabolism processes in 15N-labeled swine. 2. Fecal excretion of amino acids and 15N-labeled amino acids with diets differing in crude fiber content]. / Untersuchungen zu endogenen N-Umsatzprozessen an 15N-markierten Schweinen.

Four pigs were labelled with 15N-ammonium salt over a period of 10 days in the feeding of a fishmeal diet, a fishmeal diet + partly hydrolysed straw meal, a field bean diet and a field bean diet + partly hydrolysed straw meal. The 14N-amino acids and the 15N-amino acids excreted in faeces showed highly significant correlation coefficients with the increasing content of crude fibre in the diets, which amounted to 3.0, 5.3, 10.0 and 12.1% in the DM. The following sequence was established for the growth angle (tan alpha) of the essential 14N-amino acids: Leu, Lys, Arg, Thr, Phe, Ile, Val, His and of the 15N-amino acids: Lys, Arg, Val, Leu, Ile, Thr, Phe and His. As Lys, His and Thr cannot incorporate 15N in transamination reactions in the intermediate metabolism, their level of labelling was considerable in case of diet 4. Nevertheless, tan alpha is highest for 15N-Lys and lowest for 15N-His. This means that His in contrast to Lys, parallel to increased synthesis, is also increasingly decomposed in the large intestine. In contrast to this, proline was not labelled with 15N even with the highest content of crude fibre in the diet. Despite this, 14N-proline excretion, next to glutamic acid, increased most with the growing content of crude fibre in the diet. Due to the hydrophilic character of glutamic acid and the increased water influx in the large intestine and the increased content of crude fibre in the diet, a growing proline transport parallel to the increased influx of crude fibre and water must be assumed. If the growth angle tan alpha for the excretion of 14N-amino acids is ascertained regressively for a crude fibre content of diet of 10%, one can prove from the proportion of the amino acids and a comparison from literature for faecal bacteria and ileum digesta that the amino acid composition for this measuring point largely corresponds to that of bacteria protein.

[Endogenous nitrogen metabolism in 15N-labeled swine. 1. Course of 15N-labeling and 15N excretion in urine and feces under 4 different diets]. / Untersuchungen zu endogenen N-Umsatzprozessen an 15N-markierten Schweinen. 1. Mitteilung. Verlauf der 15N-Markierung und 15N-Ausscheidung über Harn und Kot bei Fütterung von 4 verschiedenen Diäten.

Four male castrated pigs (55-65 kg) either received a wheat--fish meal diet (1 and 2) or a wheat--horse bean diet (3 and 4) without straw meal supplement (1 and 3) or with a supplement of 20% DM partly hydrolysed straw meal to the DM of the ration (2 and 4). In order to investigate whether a 15N-labelling of the pigs is also possible with a protein excess in the ration, the animals 1 and 2 received 24.8 g and the animals 3 and 4 = 11.6 g crude protein/kg0,75 live weight. During a 10-day 15N-labelling 385 mg 15N-excess (15N') per kg0,75 were applied in a mixture of ammonia acetate and ammonia chloride in the feed. During the period of 15N-labelling the following quotas of the applied 15N-amount were incorporated: 1 = 10.2%, 2 = 7.2%, 3 = 18.7%, 4 = 14.4%. 15N-excretion in both TCA fractions of faeces showed a highly significant positive correlation to the increasing content of crude fibre in the 4 diets. The immediate 15N-incorporation into the TCA-precipitable fraction of faeces (from the 2nd of the beginning of the 15N-application onwards) proves that 15N enters the large intestine endogenously (probably as 15N-urea) and serves bacterial protein synthesis. Three days after the last 15N-application the pigs were killed. The following values of atom-% 15N' could be determined in the TCA-precipitable blood plasma and in the TCA-precipitable fraction of the liver: 1 = 0.18 and 0.19 resp., 2 = 0.22 and 0.27 resp., 3 = 0.22 and 0.23 resp. and 4 = 0.24 and 0.26 resp. The other examined organs and tissues showed smaller differences between the test animals. The following atom-% 15N' were measured in the TCA-precipitable fractions on an average of the 4 test pigs: kidney = 0.20, pancreas = 0.18, intestinal wall tissue, duodenum = 0.18, jejunum (beginning) = 0.17, jejunum (end) = 0.15, ileum = 0.15, caecum = 0.16, colon (beginning) = 0.15, colon (middle) = 0.14, colon (end) = 0.13, stomach (cardia) = 0.11, stomach (fundus) = 0.12, spleen = 0.13, heart = 0.12, skin = 0.07 and skeleton muscles = 0.06. The results show that the 15N-labelling of tissues and organs of pigs is also possible at a high level of protein supply by means of an oral application of 15N ammonia salts.

[Measurement of ileal protein digestibility using 15N-labeled rats]. / Untersuchungen zur Messung der ilealen Proteinverdaulichkeit an 15N-markierten Versuchsratten.

After 15N-labelling over 7 days male albino rats (92-95 g live weight) received either a wheat or whole egg diet (10 animals each) for 4 days. On the following day of the experiment 5 animals each continued to receive their diets as their morning meal (group 1 whole egg, group 3 wheat) and 5 animals each after the previous feeding of a wheat diet received a 2.9 g whole egg diet (group 2) and after the previous feeding of a whole egg diet a 2.85 g wheat diet (group 4) resp. This morning meal was supplemented with chromium(III)oxide. The rats consumed their meals within 20 minutes. The animals were killed 3.5 hours after the beginning of feed intake. At that time the following relative amounts (in % of the intake) could be detected in the stomach in the sequence of groups 1 to 4: Cr2O3 = 22.5; 26.5; 57.5 and 64.2; dry matter = 25.4; 22.1; 43.2 and 38.5. The better agreement between the whole egg diet and Cr2O3 can be explained with the hydrophobic qualities of Cr2O3 and the small disposition of the Cr2O3 to decompose in combination with the whole egg diet. In the first third of the small intestines less than 1% of the intake of Cr2O3 and a maximum of 3.5% of the DM could be detected. Between 20 and 36% of the Cr2O3 and between 15 and 20% of the dry matter intake were ascertained in the small intestines as a whole; in the large intestines the values were 12-20% of the Cr2O3 and 16-23% of the DM. Endogenous 15N-secretion could be ascertained in all parts of the digestive tract. According to the method suggested by U. Bergner and H. Bergner (1982), protein digestibility in the last third of the small intestines was calculated as follows: (formula; see text) The following ileal digestibility values were calculated for crude protein: whole egg = 95.6%; whole egg (wheat previously) = 95.5%; wheat = 94.1%; wheat (whole egg previously) = 85.1%. It is a precondition for the application of this method that at the time of killing representative quotas of the diet sample to be tested can be detected both in the stomach and the large intestine so that the decrease of 15N-labelling in the ileum is actually caused by the test protein.

[Examination of protein digestibility in individual intestinal segments under in vivo conditions in experimental rats by the isotope dilution method]. / Prüfung der Proteinverdaulichkeit in einzelnen Darmabschnitten unter in vivo-Bedingungen an Versuchsratten nach der Isotopenverdünnungsmethode.

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.

[Absorption of 14C-leucine and 15N-leucine in rats after feeding a fish meal diet in comparison with a gelatin diet]. / Untersuchungen zur Resorption von 14C-Leuzin und 15N-Leuzin nach Fütterung einer Fischmehldiät im Vergleich zu einer Gelatinediät an Versuchsratten.

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.

[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]. / Eine neue Methodik zur Prüfung der Qualität von Nahrungsproteinen für den Erhaltungsstoffwechsel. 2. (Mitteilung) Untersuchungen zur 15N-Ausscheidung über den Kot von 15N-markierten Versuchsratten nach Fütterung verschiedener Proteinträger.

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)

[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]. / Eine neue Methode zur Prüfung der Qualität von Nahrungsproteinen für den Erhaltungsstoffwechsel. 1. Mitteilung. Untersuchungen zur Höhe der 15N-Ausscheidung über den Harn von 15N-markierten jungen Versuchsratten nach Fütterung verschiedener Proteinträger.

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.

[Behavior of Ethephon residues on tomatoes. Part I. Green house tomatoes]. / Zum Rückstandsverhalten von Ethephon an Tomaten. 1. Mitt. Gewächshaustomaten.

The preparation Flordimex, which contains Ethephon (2-chloroethanephosphonic acid) as the active ingredient, is used for accelerating the ripening of tomatoes. During the years 1974--1977, tomato samples from 89 experiments were tested for Ethephon residues. The determination was performed gas chromatographically using alkali flame ionization detector as 2-chloroethanephosphonic acid dimethyl ester; the detection limit of the method was 0.01 mg/kg. The observed results must be evaluated on the basis of the permissible value (1 mg/kg) stipulated for vegetables by the Ministry of Health of the GDR. 1--2 days after the use of concentrations of 0.1%, 0.2%, 0.3% and 0.4%, respectively, the following mean residue values were found: 0.31, 0.50, 0.39 and 0.91 mg/kg, respectively, which decreased but slowly. This leads to the conclusion that formulation concentrations of more than 0.3% and applications of more than 6 1/ha should not be allowed by the Ministry. In case of repeated uses, 3-week intervals are imperative. Under the above-mentioned conditions of use, the mean residue values determined 4--5 days after application approximated 0.6 mg/kg. This period is to be regarded as a tentative waiting-period that must be respected after the treatment of glasshouse tomatoes with Flordimex.

[Secretion of radioactively labeled amino acids into the digestive tract. 4. 14C label and 14C-leucine in the digestive tract following subcutaneous injection of 14C-leucine in rats after ligation of the pancreas]. / Die Sekretion von radioaktiv markierten Aminosäuren in den Verdauungstrakt.

Secretion into the Gastro-Intestinal Tract of Amino Acids Labelled with Radioactive Isotopes. (4) 14C-Labelling and 14C-Leucine in the Gastro-Intestinal Tract after Subcutaneous Injection of 14C-Leucine to Rats with Tied-off Pancreatic Gland.

[Relationships between the apparent digestibility of crude protein and the amino acid balance of the swine digestive tract]. / Beziehungen zwischen der scheinbaren Verdaulichkeit des Rohproteins und der Aminosäurenbilanz des Verdauungstraktes bei Schweinen.

A diet of equal composition (88% barley, 5% extracted sunflower meal, 3% fishmeal and 3% yeast) was subjected to 9 different forms of thermal treatment and fed to experimental pigs. The biological value of the proteins was found to decline from 65.9 below 50. The amino acid balance of the digestive tract ("true digestibility of amino acids" according to other authors) proved to deteriorate due to the thermal treatment. The individual amino acids always revealed highly significant positive correlations with the apparent digestibility of crude protein. This finding is related with the often demonstrated fact that the fecal protein always has a constant amino acid composition, irrespective of feed protein and, consequently, only influences the quantitative fecal protein secretion, i. e. the amino acid balance of the digestive tract which is suggested to be the cause of the mathematical relations shown.

[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]. / Die Sekretion von radioaktiv markierten Aminosäuren in den Verdauungstrakt. 3. 14C-Markierung der Darmwand nach subkutaner Injektion von 14C-L-Leuzin an Ratten.

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.

[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]. / Die Sekretion von radioaktiv markierten Aminosäuren in den Verdauungstrakt

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.

[Secretion of radioactively labeled amino acids into the digestive tract. I. Report 14C labeling of the pancreas after subcutaneous injection of 14C-leucine in rats]. / Die Sekretion von radioaktiv markierten Aminosäuren in den Verdauungstrakt

4 different groups of experimental animals (rats) were injected 14C leucine at 4 different levels of specific 14C activity. Groups A and B received a dosis of leucine corresponding to the daily leucine requirements of the animals. The specific 14C activity was high in group A and low in group B. Groups C and D were injected a leucine dosis at a level of 10% from the groups A and B. the specific 14C activity being again high (group C) or low (group D). The results showed that a true evalution of the experiment could lnly be achieved if the values were related to the true rate of labeling (DPM/mg N or specific 14C leucine activity). The "percentage of the injected dosis" proved to be unsuitable for the analysis of the experimental results when taken as reference frame. The levels of specific 14leucine activity in free plasma leucine were in the same order as the specific activities of the injected solutions (C greater than A greater than D greater than B) whereas the order of specific 14C leucine activities in the TCE-soluble fraction of the pancreatic gland (TCE-trichloroacetic acid) was found to be A greater than C greater than B greater than D. This was due to the higher rate of 14C-leucine transfer into the protein fraction in the animals of group C and D receiving a normal supply of leucine. In these groups an equilibrium in specific 14C-leucine activity between the TCE-soluble and TCE-precipitable fractions was achieved 20-30 mins after injection. A relatively high degree of labelling of the pancreatic protein was noted as early as about 2 minutes after the injection of 14C-leucine. This indicates that in studies on amino acid absorption the secretion of those amino acids that are first absorbed and then resecreted via the pancreatic gland should always be taken into account.

[Residue retention of ethephon on stone fruits and berries. 2. Ethephon residues in currants and gooseberries]. / Zum Rückstandsverhalten von Ethephon auf Stein- und Beerenobst. 2. Mitt. Ethephon-Rückstände auf Johannis- und Stachelbeeren

Studies on the residual behaviour of Ethephon on black and red currants showed that the fruits contained on an average 0.39, 0.81, 2.2 and 0.64, 1.14, 1.04 p.p.m. of Ethephon, respectively, after application of 0.04, 0.06 and 0.08%. Flordimex mixture. When a concentration of 0.08% was applied to gooseberries, the fruits contained on an average 0.31 p.p.m. of Ethephon. The juice of black currants contained relatively larger residues.

[Behavior of Ethephon residues on stone fruits and berries. 1. Ethephon residues on sweet and sour cherries]. / Zum Rückstandsverhalten von Ethephon auf Stein- und Beerenobst 1. Mitt. Ethephon-Rückstände auf Süss- und Sauerkirschen

The authors describe a gas chromatographic method for determing Ethephone residues. Studies on the residual behaviour of Ethephon on sweet cherries showed that the fruits contained 0.88, 1.45 and 1.83 p.p.m. of Ethephon after applications of 0.05, 0.075 and 0.1% Flordimex mixture, respectively. When the same doses were applied to sour cherries, the fruits contained 0.54, 1.12 and 1.44 p.p.m. of Ethephon; and the juices, 0.81, 1.36 and 1.77 p.p.m.