scholarly journals Metabolism of heat-damaged proteins in the rat

1971 ◽  
Vol 26 (2) ◽  
pp. 311-322 ◽  
Author(s):  
J. E. Ford ◽  
C. Shorrock
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Total Amino Acid ◽  
Carbohydrate Complex ◽  
Urinary Peptide

1. Freeze-dried cod muscle and casein were subjected to various conditions of heat treat-ment. Diets containing the different products, or the unheated materials, were given to a group of four adult male rats during successive 48 h periods, and urine was collected during the second 24 h of each 48 h period. A further collection of urine was made from the rats after they had been given protein isolated from heated skim-milk powder. The content and amino acid composition of the ‘peptide’ and ‘free amino acids’ in the urines were determined.2. Heat damage to the cod-fillet protein increased the total urinary excretion of peptide-bound amino acids, from 18·6 to 48·8 µmol/rat.d. The composition of the peptide also changed, and in particular there was a marked increase in lysine, from 2·98 to 20·30 µmol %. Three amino acids - lysine, aspartic acid and glutamic acid - together comprised nearly 70 % of the total amino acid residues. There was a corresponding increase in urinary excretion of free amino acids, from 53·7 to I 14·4 µmol/rat.d. The combined losses of lysine in urinary peptide and free amino acids were 1·5 % of the total lysine ingested, as against 0·3 % for the unheated cod fillet.3. The effects of similar heat treatment of casein on the composition of the urinary peptide and free amino acids were less marked. There was no increase in total urinary peptide excretion and there was a smaller increase in the lysine content of the peptide.4. In urine of rats given protein isolated from heated skim-milk powder, the peptide hydro-lysate was rich in lysine and in furosine, which together comprised 41 mol % of the total amino acid composition. These compounds were presumably formed, together with a smaller quantity of pyridosine, from lysine-carbohydrate complex in the urine. It is probable that, as compared with free lysine, the lysine-carbohydrate complex was absorbed relatively in-efficiently from the rat intestine.5. The findings are discussed in relation to the wider question of the metabolism of the ‚unavailable peptide’ that is released in the course of digestion of heat-damaged protein.

scholarly journals Amino acid oxidation by young pigs receiving diets with varying levels of sulphur amino acids

1983 ◽  
Vol 50 (2) ◽  
pp. 383-390 ◽  
Author(s):  
Kyu-Il Kim ◽  
Henry S. Bayley
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Choline Chloride ◽  
Milk Powder ◽  
Skim Milk ◽  
Essential Amino Acids ◽  
Acid Oxidation ◽  
Amino Acid Requirement

1. Piglets were weaned at 3 d of age and were introduced to liquid diets in which 400 g/kg protein was supplied as skim-milk powder and the balance as a mixture of free amino acids. The skim milk contributed 2·3 g methionine and 1·4 g cystine/kg diet; the experimental diets were made by supplementing these levels with free amino acids.2. The adequacy of the test level of the amino acid in the diet was assessed by measuring the oxidation of [1−14]phenylalanine as an indicator of the partition of the essential amino acids between incorporation into protein and degradation. Radioactivity recovered as carbon dioxide was used as a measure of catabolism.3. Addition of 0·2, 0·4, 0·7, 1·2 and 1·7 g L-methione/kg to a diet containing 5 g cystine and 3 g choline chloride/kg showed that phenylalanine catabolism was minimal for the diet with 2·7 g methionine/kg indicating that this is the dietary requirement for methionine to serve as a source of methionine residues for protein synthesis.4. Addition of D-methionine to produce a series of diets with graded levels of methionine showed that the D-isomer was less effective than the L-isomer in reducing phenylalanine catabolism: the addition of 0·8 g D-methionine/kg diet was needed to produce the same effect as 0·4 g L-methionine/kg diet showing that the replacement value of D-methionine for L-methionine was 50% in the young pig.5. To investigate the influence of cystine on methionine requirement, diets with varying levels of methionine and cystine were prepared. Oxidation of [U-14C]methionine was used as an indication of an excess of methionine, and the results showed that increasing the dietary methionine level above 3·0 g/kg in diets containing 1·4 g cystine/kg provided an excess of methionine for oxidation. This indicated a sulphur amino acid requirement of 4·4 g/kg, one-third of this being supplied as cystine.

scholarly journals Nitrogen Storage and Its Interaction with Carbohydrates of Young Almond Trees in Response to Nitrogen Supply

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 796C-796
Author(s):  
Guihong Bi* ◽  
Carolyn Scagel ◽  
Lailiang Cheng ◽  
Leslie Fuchigami
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Total Amino Acid ◽  
Total N ◽  
N Supply ◽  
N Assimilation ◽  
Predominant Amino Acid ◽  
Total Amino Acids

June-budded `Nonpareil/Nemaguard' almond (Prunus dulcis (Mill) D.A. Webb) trees were fertigated with one of five nitrogen (N) concentrations (0, 5, 10, 15, or 20 mm) in a modified Hoagland's solution from July to September. In October, the trees were sprayed twice with either water or 3% urea, then harvested after natural leaf fall and stored at 2°C. Trees were destructively sampled during winter storage to determine their concentrations of amino acids, protein, and non-structural carbohydrates (TNC). Increasing N supply either via N fertigation during the growing season or with foliar urea applications in the fall increased the concentrations of both free and total amino acids, whereas decreased their C/N ratios. Moreover, as the N supply increased, the proportion of nitrogen stored as free amino acids also increased. However, protein was still the main form of N used for storage. The predominant amino acid in both the free and total amino-acid pools was arginine. Arginin N accounted for an increasing proportion of the total N in both the free and total amino acids as the N supply was increased. However, the proportion of arginine N was higher in the free amino acids than in the total amino acids. A negative relationship was found between total amino acid and non-structural carbohydrate concentrations, suggesting that TNC is increasingly used for N assimilation as the supply of N increases. Urea applications decreased the concentrations of glucose, fructose, and sucrose, but had little influence on concentrations of sorbitol and starch. We conclude that protein is the primary form of storage N, and that arginine is the predominant amino acid. Furthermore, the synthesis of amino acids and proteins comes at the expense of non-structural carbohydrates.

scholarly journals Influence of dietary protein concentration on the oxidation of phenylalanine by the young pig

1986 ◽  
Vol 55 (3) ◽  
pp. 651-658 ◽  
Author(s):  
Ronald O. Ball ◽  
Henry S. Bayley
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
G Protein ◽  
Dietary Protein ◽  
Free Amino Acids ◽  
Free Amino ◽  
Crude Protein ◽  
Protein Concentration ◽  
Skim Milk ◽  
Intact Protein

1. Piglets were weaned at 3 d of age and reared to 2.5 kg on a liquid diet in which the protein was supplied by dried skim milk and a mixture of free amino acids. The oxidation of L-[l-14C]phenyIalanine was measured as an indication of the partition of amino acids between retention and catabolism in pigs (2.5 kg) offered meals containing vaned concentrations of crude protein (nitrogen x 6.25).2. The dietary protein concentration was varied either by increasing the inclusion of a mixture of free amino acids in a series of diets containing 100 g protein/kg from skim milk, or by increasing the level of inclusion of the skim milk in a series of diets containing the equivalent of 100 g protein/kg from the free amino acid mixture.3. The oxidation of phenylalanine was minimized by dietary protein concentrations of 240 and 258 g/kg for the diets containing increasing concentrations of free amino acids or skim milk respectively.4. These results show that a mixture of free amino acids is used more effectively than intact protein for promoting retention of essential amino acids.5. The recovery of radioactivity in expired carbon dioxide was inversely related to the recovery of radioactivity in liver tissue when the concentration of dietary crude protein was increased from deficient to adequate, demonstrating that the fractional oxidation of the indicator amino acid was inversely related to protein synthesis.

scholarly journals Impact of Bovine Diet on Metabolomic Profile of Skim Milk and Whey Protein Ingredients

Metabolites ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 305 ◽  
Author(s):  
Jonathan B. Magan ◽  
Tom F. O’Callaghan ◽  
Jiamin Zheng ◽  
Lun Zhang ◽  
Rupasri Mandal ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Perennial Ryegrass ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Total Amino Acid ◽  
Sweet Whey ◽  
Acid Whey

The influence of bovine diet on the metabolome of reconstituted skim milk powder (SMP) and protein ingredients produced from the milk of cows fed on pasture or concentrate-based diets was investigated. Cows were randomly assigned to diets consisting of perennial ryegrass only (GRS), perennial ryegrass/white clover sward (CLV), or indoor total mixed ration (TMR) for an entire lactation. Raw milk obtained from each group was processed at pilot scale, to produce SMP and sweet whey, and SMP was further processed at laboratory scale, to yield ideal whey and acid whey. The total amino acid composition and metabolome of each sample were analyzed, using high-performance cation exchange and a targeted combination of direct-injection mass spectrometry and reverse-phase liquid chromatography–tandem mass spectrometry (LC–MS/MS), respectively. The nitrogen composition of the products from each of the diets was similar, with one exception being the significantly higher nonprotein nitrogen content in TMR-derived skim milk powder than that from the GRS system. Total amino acid analysis showed significantly higher concentrations of glycine in GRS- and CLV-derived sweet whey and acid whey than in those from TMR. The cysteine contents of CLV-derived ideal whey and acid whey were significantly higher than for TMR, while the valine content of GRS-derived acid whey was significantly higher than TMR. The phenylalanine content of GRS-derived ideal whey was significantly higher than that from CLV. Metabolomic analysis showed significantly higher concentrations of the metabolites glutamine, valine, and phosphocreatine in each ingredient type derived from TMR than those from GRS or CLV, while the serine content of each GRS-derived ingredient type was significantly higher than that in TMR-derived ingredients. These results demonstrate that the type of bovine feeding system used can have a significant effect on the amino acid composition and metabolome of skim milk and whey powders and may aid in the selection of raw materials for product manufacture, while the clear separation between the samples gives further evidence for distinguishing milk products produced from different feeding systems based on LC–MS/MS.

scholarly journals Determination of amino acid requirements of young pigs using an indicator amino acid

1983 ◽  
Vol 50 (2) ◽  
pp. 369-382 ◽  
Author(s):  
Kyu-Il Kim ◽  
Ian McMillan ◽  
Henry S. Bayley
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Essential Amino Acid ◽  
Free Amino ◽  
Skim Milk ◽  
Linear Increase ◽  
Deficient Diet ◽  
Direct Estimate ◽  
Phenylalanine Level

1. Mixtures of skim milk and free amino acids were compared as diets for pigs which would allow manipulation of dietary amino acid levels. Piglets gained 208 g/d between 3 and 14 d of age on the skim-milk diet, but replacement of 600 g/kg of the dietary nitrogen with free amino acids reduced growth rate to 148 g/d.2. Supplementation of a lysine-deficient diet with lysine reduced the catabolism of [14C]phenylalanine showing that phenylalanine catabolism could be used as an indicator of the adequacy of diet with respect to another essential amino acid.3. The dietary level of phenylalanine which would provide an excess for catabolism by the piglet was estimated directly by measuring the influence of dietary phenylalanine level on [14C]phenylalanine oxidation. Reduction of the dietary phenylalanine level below 7 g/kg had no effect on phenylalanine oxidation, whereas increasing the dietary phenylalanine level above 7 g/kg resulted in a linear increase in phenylalanine oxidation.4. An indirect estimate of histidine requirement was made by examining the influence of dietary histidine level on [14C]phenylalanine oxidation. In diets containing more than 4 g histidine/kg, phenylalanine oxidation was minimal. In diets containing less than 4 g histidine/kg, [14C]phenylalanine oxidation increased as the level of dietary histidine was reduced. This showed that the utilization of the essential amino acid phenylalanine, for protein synthesis, was not limited by histidine supply in diets containing more than 4 g histidine/kg.5. A direct estimate of histidine requirement was made by examining the influence of dietary histidine level on [14C]histidine oxidation. Diets with more than 4 g histidine/kg contained an excess which was catabolized: there was a linear increase in histidine oxidation in response to dietary histidine levels greater than 4 g/kg. This confirmed the previous indirect estimate of histidine requirement.

Changes in proteins and free and total amino acids of peanuts (Arachis hypogaea) infected with Aspergillus parasiticus

1975 ◽  
Vol 53 (22) ◽  
pp. 2639-2649 ◽  
Author(s):  
John P. Cherry ◽  
Clyde T. Young ◽  
Larry R. Beuchat
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Arachis Hypogaea ◽  
Free Amino Acids ◽  
Free Amino ◽  
Aspergillus Parasiticus ◽  
Amino Acid Content ◽  
Total Amino Acid ◽  
Sequence Of Events ◽  
Total Amino Acids

Protein and amino acid composition of peanuts (Arachis hypogaea L.) inoculated with Aspergillus parasiticus Speare were compared with those of non-infected seeds during an 18-day test period to determine metabolic changes within this interrelationship. The levels of buffer-soluble proteins of infected peanuts decreased rapidly to quantities much lower than those of non-infected seeds shortly after inoculation. Simultaneously, the levels of insoluble proteins increased to quantities greater than those contained in soluble fractions. Gel electrophoresis of soluble extracts from inoculated peanuts showed that proteins were hydrolyzed to many small-molecular-weight components, which eventually disappeared as fungal growth progressed. A corresponding increase in quantity of most free amino acids was observed shortly after inoculation of the peanuts. Major changes in free amino acid content coincided with substantial alterations of proteins in both soluble and insoluble fractions. These data suggested that inoculation of peanuts with A. parasiticus initiated a sequence of events whereby proteins were hydrolyzed first to small polypeptides and (or) insoluble components, then to free amino acids. After extended periods of infection, levels of free amino acids varied from day to day, suggesting that differential utilization of these components by the fungus was occurring. Quantities of total amino acids in whole seeds and soluble and insoluble fractions were different for non-inoculated and inoculated peanuts. Distinct differences were especially notable among samples of these three fractions of inoculated seeds. Differences in total amino acid contents apparently reflect qualitative and quantitative changes in proteins and (or) polypeptides present in various fractions examined during the infection period.

PARTIAL REPLACEMENT OF SKIM MILK WITH FREE AMINO ACIDS IN DIETS FOR THE PIGLET

1984 ◽  
Vol 64 (4) ◽  
pp. 1019-1022 ◽  
Author(s):  
R. O. BALL ◽  
K. I. KIM ◽  
H. S. BAYLEY
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Control Diet ◽  
Skim Milk ◽  
Partial Replacement ◽  
Synthetic Diet ◽  
Acid Diet ◽  
Amino Acid Requirements

A semi-synthetic diet in which 60% of the nitrogen from dried skim milk was replaced with a mixture of free amino acids supported gains of 236 g/day between 3 and 18 days of age, as compared with a gain of 282 g/day for a control diet in which skim milk provided all the protein. Neutralizing the acidity of the free amino acid diet increased its palatability. All of the indispensible amino acids may be made deficient in the experimental diet, thus providing the opportunity to evaluate the amino acid requirements of the piglet. Key words: Piglets, growth, amino acids, semi-synthetic diet

Free amino acids in the blood of fetal and maternal Weddell seals

1982 ◽  
Vol 242 (1) ◽  
pp. R85-R88
Author(s):  
B. J. Murphy ◽  
P. W. Hochachka ◽  
W. M. Zapol ◽  
G. C. Liggins
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Concentration ◽  
Free Amino Acids ◽  
Free Amino ◽  
Gravid Female ◽  
Weddell Seal ◽  
Amino Acid Concentration ◽  
Total Amino Acid ◽  
Weddell Seals

The content of free amino acids in whole blood was measured in near-term gravid female Weddell seals (Leptonychotes weddelli) and compared with fetal amino acid profiles during rest and during experimental diving. With the exception of taurine and glutathione, Ninhydrin-reactive components of acid extracts of blood occurred in higher concentrations on the fetal side of the placenta than on the maternal side. Compared with humans the Weddell seal displayed higher ratios of fetal arterial to maternal arterial levels for aspartate, glycine, alanine, valine, tyrosine, phenylalanine, and total branched-chain amino acids. In the resting state the total free amino acid concentration in maternal blood was only about 70% as large as the total amino acid concentration in fetal blood, compared with a value of over 80% for humans. Only modest changes in the concentrations of specific amino acids occurred during simulated awake diving, but the overall maternal pools of glycine, glutamate, and glutamine were augmented, creating favorable conditions for uptake by the fetus.

scholarly journals The amino acid composition of cotyledons, testa, embryo and protein fractions of bean seeds

2013 ◽  
Vol 41 (1) ◽  
pp. 69-75
Author(s):  
Ryszard Kosson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Total Nitrogen ◽  
Acid Content ◽  
Free Amino Acids ◽  
Free Amino ◽  
Amino Acid Content ◽  
Total Amino Acid

The contribution of cotyledons, embryo and testa to the whole seed, was analyzed in the bean cultivar, Wiejska. The total nitrogen content and amino acid composition of morphological parts of the seed were determined. The average amino acid composition of globulins and albumins and the content of free amino acids in seeds of six Polish cultivars were estimated as well. It was found that the embryo contained the highest quantity of total nitrogen and the lowest of protein nitrogen. The exogenous amino acid content in the embryo was higher than in cotyledons and testa. Both albumins and globulins were shown to contain 42% exogenous amino acids. The content of methionine - the first limiting amino acid of bean proteins - did not exceed 0.30% of the total amino acid content in albumins and globulins. Free glutamic and aspartic acids made up more than 60% of the total free amino acids.

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