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H D Bock

Publications and source records attributed to H D Bock.

30 records · Page 2Linked to original sources
PubMed1979

[The protein digestibility and amino acid absorption in various segments of the digestive tract of pigs. 6. Results of the application of 15N-lysine].

From two fattening pigs (average live weight 63 kg) with re-entrance cannulae both in the duodenum and the ileocecal region, the intake, the excretion and the flow rates of nitrogen, 15N, lysine and 15N-lysine are measured after the oral application of 15N-lysine as supplement of a wheat-wheat gluten diet. A scheme of the lysine metabolism of pigs is drawn on the basis of the measured values. The absorption of synthetic and native lysine as well as the endogenous and exogenous lysine contents of the duodenal and ileum chyme are estimated.

Amino Acids↗
PubMed1978

[Nutrient composition of some newly bred high protein and/or high lysine grains and their digestibility determined on growing pigs].

With the view to complementing the feedstuff data store and, consequently, to further improving the GDR Feed Evaluation System, some newly bred high-protein and/or high-lysine cereal varieties and strains (spring barley, winter wheat, maize) were studied for their nutrient composition and digestibility. Apart from from WEENDER's feed analysis technique, more recent methods were applied to determine total fat (after HCl treatment), carbohydrates (enzymatic method), lignin and amino acids. The digestibility of the nutrients was determined using growing pigs of different live weight, the test rations being made up of the cereals under and supplementations of limiting amino acids as well as vitamins and minerals. In comparison with the values from currently applied tables, the newly bred strains and varieties proved to have markedly higher contents of crude protein, digestible crude protein, lysine and energetic feed equivalents. Compared to crude fat, the total fat values proved markedly higher in the barley and wheat samples. The readily soluble and easily hydrolizable carbohydrates found with the new analysis procedure suggested, were 100% digestible in all cereal samples used. Lignin proved the constituent most difficult to digest and must be regarded as virtually undigestible in the case of pigs.

Animal Nutritional Physiological Phenomena↗
PubMed1978

[Influence of sex and live body mass on the true protein and amino-acid digestibility of various animal feeds in pigs. 1. Comparative studies between barrows and female pigs].

Growing barrows and female pigs of 3 liveweight ranges (20-30 kg, 50-60 kg, 80-90 kg) were used to study the true digestibility of protein and essential amino acids from 4 cereal species and 4 high-protein concentrate using the fecal analysis method and regression techniques. No significant differences were found between the females and the barrows in the true digestibility of the protein and most of the amino acids from the protein carriers under study. In the 3rd liveweight range, the true digestibility of some amino acids of the cereals proved somewhat lower in tendency with female animals. In comparison with the true digestibility of protein, in the cereals under study that of lysine gave significantly lower, and that of cystine, arginine, phenylalanine and histidine significantly higher values. The relative values (protein = 100%) were 85.0, 110.6, 106.8, 106.5 and 105.5 for lysine, cystine, arginine, phenylalanine and histidine, respectively. The true digestibility of the remaining amino acids is comparable to that of protein.

Amino Acids↗
PubMed1978

[Amino acid composition of non-absorbed peptide fractions in rat small intestines. III. Feeding of wheat gluten and molasses yeast. Essential amino acid content of feces].

The authors investigated the nitrogen content of different fractions and in particular the aminoacid composition of the trichloroacetic acid (TCA)-precipitable and TCA-soluble peptides in the distal small intestine of rats which had been fed experimental diets (nitrogen-free or containing casein, wheat gluten or molasses yeast as a protein carrier). Parallel with this, they determined in growing rats the nitrogen and amino-acid digestibility of molasses yeast and wheat gluten according to the technique of faecal analysis, and studied the amino-acid composition of the faecal protein. Independently of the dietary protein fed, the peptide fractions of the content of the intestine showed an amino-acid composition that was largely similar to that found in case of nitrogen-free diet. The amino-acid composition of the faecal protein is, independently of the dietary protein given, relatively constant and corresponds approximately to the intestinal loss protein. There is agreement between the amino-acid composition of the TCA-precipitable peptide fractions and those of the corresponding faecal proteins. These components seem to be of endogenous origin.

Amino Acids↗
PubMed1976

[Problem of nitrogen metabolism in monogastric animals].

A new method has been developed for determining the proportion of endogenic and exogenic faecal N by measuring the degree of specific labelling in the feeding-stuff (administered orally) and in the excreta (faeces and urine). The method has also been developed to find out whether the endogenic excretion of intestinal N is actually independent of the N intake. The present technique had been worked out on the basis of the model that had been originally established by Czarnetzki et al. in 1969 with the aim of characterizing processes of nitrogen metabolism in monogastric animals. As a result, a multi-compartment model was developed and a number of conclusions were derived from it. These conclusions were tested in 3 series of experiments on rats fed 15N labelled spring barley and 15N labelled feed yeast. Additionally, 15N labelled experimental rats were used receiving unlabelled extracted soya bean meal. The proportion of endogenic intestinal nitrogen (DVN) varied between 15-22% relative to the proportion of N ingested. The relative proportion of endogenic faecal N in the tota faecal N was found to be 100% in the case of the nitrogen-free diet. With increasing levels of dietary N this proportion lended to decrease down to a final value that was quite characteristic for each partitular feeding-stuff. The absolute amount of endogenic faecal N, however, was found to increase with increasing N levels. This shows that contrary to current views, DVN is not constant and is not independent of protein intake. Rather, a close relationship was found to exist between the level of N intake and DVN excretion (r = 0.951...0.972). So, the proportion of exogenic N contained in the faeces is much smaller than was previously assumed on the basis of the classical and regressive methods. These were based on the assumption that DVN is constant. Consequently, higher digestibility values will be obtained in comparison with those calculated on the basis of the previous methods. Digestibility data for spring barley increased from 83.9 to 95.6, i.e. by 11 digestibility units; for feed yeast there was an increase by 6.2 units, from 83.3 to 90.0; and for extracted soya bean meal an increase of 6.2 units was observed (from 90.7 to 96.9).

Animal Feed↗
PubMed1976

[The problem of the use of urea in feeding swine].

For a period of 9 days growing fattening pigs (with liveweights ranging from 40 to 50 kgs were fed a ration of autumn barley, dried skim mild and wheat gluten supplemented with 0.5% of 15N labelled urea (12.5% of the total N). The N balance and the rate of 15N protein retention as well as the rates of protein and amino acid synthesis in the different organs and tissues of the carcasses were estimated by emission spectrometry after amino acid fractionation. On an average, 19.3% of the ingested urea were retained, while only 4% N were retained in the essential amino acids found in the carcasses. This proportion will, to a large extent, result from transamination processes and, to a lesser extent, from microbia synthesis. From this it may be concluded that urea N does not induce any appreciable synthesis of amino acids in pigs so that urea cannot be regarded as a suitable substitute for protein feeds in the feeding of monogastric animals.

Animal Nutritional Physiological Phenomena↗
PubMed1975

[Evaluation of protein quality in human and animal foodstuffs].

Having mentioned the present criteria for the evaluation of the protein quality, which are almost exclusively based on a numerical value, the author explains and discusses the principles of new criteria suggested since 1969. The following criteria are presented: the "Index d'Equilibre de la Protéine" of Arnould; the criteria "Total Amino Acid Value" and "Essential Amino Acid Value", outlined by GLEM-HANSEN and EGGUM; the "Nitrogen Efficiency Ratio" of EGGUM; the model of a nitrogen balance function, developed by RUFEGER; the multicompartment model for studying the resorption and metabolism kinetics of nitrogen and amino acids, as extended by KRAWIELITZKI; the functional conception of the relationships between the parameters of the nitrogen metabolism and of the laws of growth, according to GEBHARDT, and the method for determining the true amino-acid digestibility according to DAMMERS [7], EGGUM [8], WIESEMULLER [23], POPPE and co-workers [19], UHLEMANN [22] and HERRMANN [12]. Finally, the author gives suggestions for further research on the evaluation of protein quality.

Amino Acids↗
PubMedDate not supplied

[Protein digestibility and the absorption of amino acids in various segments of the digestive tract of pigs. 4. Digestibility of crude protein and amino acids and rate of passage through the duodenum and ileum and the total digestive tract of growing pigs].

The crude protein digestibility and the amino acid absorption of six female pigs (average live weight 61 kg) with duodenal and ileocecal re-entrant cannulae, which were fed with a wheat + wheat gluten + lysine ration and an N-free ration, were determined in various segments of the intestines. Comparative experiments concerning the N-metabolism with pigs without and with cannulae showed that the animals renormalised their metabolism 14 days after narcosis and fistulation of the intestines. The extents of secretion and absorption of the various amino acids vary as it is shown from the values of the apparent and true digestibility resp. rate of passage through various segments of the intestines. While for methionine and glutamic acid absorption exceeds endogenous secretion already in the duodenum, the amino acids with a high endogenous quota (glycine, alanine, threonine, tryptophan) are, even at the terminal ileum, not as well absorbed as the others. Methionine is obviously synthesised on a large scale by the colon flora and excreted in feces. The fractionation of the duodenal and ileum chyme after feeding wheat + wheat gluten + lysine as well as N-free mixture, into the fractions "solid particles", "peptides-free amino acids" and "proteines precipitable by trichlor-acetic acid" supplies information on the degree of protein degradation in various segments of the intestines.

Amino Acids↗
PubMedDate not supplied

[Absorption and utilization of amino acids infused into the cecum of growing swine. 3. Studies with 15N- and 14C-labeled isoleucine].

In 3 experiments growing female pigs, (live weight 35-56 kg) received continuous infusions of 15N-labelled or 15N- and 14C-doubly labelled isoleucine by means of caecal cannulae. The whereabouts of the infused isoleucine were investigated. Between 8.9 and 12.3% of the infused 15N-excess (15N') was excreted in faeces mainly in the forms of bacteria protein, between 0.7 and 0.9% only of the infused amount unchanged as 15N-isoleucine. The highest quota is microbially decomposed in the colon and absorbed in the form of NH3 or amines. Between 45 and 70% of the infused 15N are excreted in urine, mainly as urea (85-95% of the 15N-amount in urine). Virtually no 15N from the infused isoleucine is incorporated in the organ and tissue proteins (exception: colon wall). These findings are corroborated by the 14C-activity measuring as no intact 14C labelled isoleucine could be detected in the tissue protein. These results show that intact isoleucine is not absorbed in the colon. The nitrogen originating from the absorbed NH3 is nearly completely excreted in urine and thus not available to the biosynthesis of body protein.

Animals↗