scholarly journals Non-essential nitrogen and protein utilization in the growing rat

1990 ◽  
Vol 64 (3) ◽  
pp. 653-661 ◽  
Author(s):  
J. Heger
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Essential Amino Acid ◽  
Essential Amino Acids ◽  
Protein Utilization ◽  
Biological Value ◽  
Growing Rats ◽  
Growing Rat ◽  
Per Se

Three series of nitrogen-balance experiments were carried out on growing rats fed on purified isonitrogenous diets (16 g N/kg) to study the importance of non-essential N and the essential:total N (E:T) ratio for attaining maximum N balance (NB) and biological value (BV) of protein. Minimum dietary levels of asparagine, proline and glutamic acid required for maximum NB and BV were estimated to be 1.0, 2.0 and 5.0 g/kg respectively. In an essential amino acid-based diet, the levels of individual amino acids were successively reduced to 110% of the requirement. Reducing the level of arginine, lysine or methionine + cystine resulted in a significant increase in NB and BV while the response of rats given the isoleucine-reduced diet significantly decreased. Addition of asparagine, proline and glutamic acid in the estimated minimum amounts to an essential amino acid-based diet resulted in a significant increase in NB and BV. A further significant increase was found when the levels of arginine, lysine and methionine + cystine in the diet were reduced to 110 % of the requirement. The performance of rats fed on the latter diet was similar to that of rats given a diet with the optimum E:T ratio. It is concluded that the optimum protein utilization may be influenced by the presence of some non-essential amino acids and by the surplus of some essential amino acids rather than by the E:T ratio per se.

scholarly journals Efficiency of utilization of essential amino acids in growing rats at different levels of intake

1985 ◽  
Vol 54 (2) ◽  
pp. 499-508 ◽  
Author(s):  
J. Heger ◽  
Z. Frydrych
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Essential Amino Acid ◽  
Essential Amino Acids ◽  
N Balance ◽  
Growing Rats ◽  
Dietary Concentration ◽  
Limiting Amino Acid ◽  
Maintenance Requirements ◽  
Different Levels

1. Nitrogen balance was studied in growing male SPF-rats fed on diets in which each essential amino acid was varied from zero to about 120% of optimum requirement. From the balance results, optimum and maintenance requirements were estimated as well as the efficiency of utilization of amino acids for growth and growth + maintenance.2. N balance increased with increasing dietary level of the deficient amino acid; the response gradually diminished as the content of the amino acid approached optimum. At zero level of intake, negative N balance was found for all amino acids except histidine. The highest loss of body N was found in the sulphur-amino-acid-free diet and the lowest one in the lysine-free diet.3. Maximal utilization of essential amino acids for growth was found at dietary levels corresponding to 30–60% of optimum requirement and ranged from about 0.65 to 0.85 except for S amino acids and histidine. The utilization of S amino acids was about 0.55 while that of histidine exceeded 1.0. The utilization of amino acids for growth-tmaintenance was maximal at the lowest levels of intake and gradually decreased as the dietary concentration of the limiting amino acid increased. At dietary levels near optimum the utilization was about 06–07, except for S amino acids where the utilization was less than 0.5.

scholarly journals Protein reserves and muscle constituents of protein-depleted and repleted cocks

1967 ◽  
Vol 21 (3) ◽  
pp. 661-670 ◽  
Author(s):  
John H. Ashley ◽  
Hans Fisher
Keyword(s):  
Amino Acids ◽  
Body Weight ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Essential Amino Acid ◽  
Essential Amino Acids ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Fish Protein

1. Body-weight changes and nitrogen balance were studied, together with the concentration of various nitrogenous muscle components, in adult cocks before and after a 6-day period on a N-free diet and again after a 16-day repletion period on diets supplying various amounts and types of dietary N.2. In the first experiment a comparison was made during the repletion period between a fish-protein supplement and a supplement of glycine + glutamic acid added to an essential amino acid mixture.3. During the depletion period the muscle concentration of RNA, DNA and of two transaminase enzymes decreased significantly; during the repletion period these components increased again significantly, and usually to levels greater than the pre-depletion concentration. There were no differences in these responses obtained during repletion with the two N supplements, although the cocks given the glycine–glutamic acid supplement differed from those receiving fish protein in being in Negative N balance and in losing body-weight during the repletion period.4. In the second experiment one group of depleted cocks was given an essential amino acid mixture alone as the dietary N source and a second group this mixture supplemented by aspartic acid.5. A decrease in RNA and in the transaminase enzymes during depletion was followed by a significant increase during repletion, but the increase was greater for the group receiving the aspartic acid than for that receiving only the essential amino acid mixture.6. It was concluded that adding non-essential amino acids to a maintenance mixture of essential amino acids will permit greater repletion in mature cocks.7. The fluctuations in concentration of RNA and of certain enzymes with dietary protein supply may well be controlling factor in the regulation of N losses and accretions during protein deficiency and sufficiency.5. The relative constancy of muscle DNA in contrast to the fluctuations in other nitrogenous muscle constituents provides additional support for the concept of protein reserves.

scholarly journals The Diverse Functions of Non-Essential Amino Acids in Cancer

Cancers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 675 ◽  
Author(s):  
Bo-Hyun Choi ◽  
Jonathan L. Coloff
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Cancer Therapy ◽  
Metabolic Pathways ◽  
Essential Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Essential Amino Acids ◽  
Redox Status ◽  
Antioxidant Systems

Far beyond simply being 11 of the 20 amino acids needed for protein synthesis, non-essential amino acids play numerous important roles in tumor metabolism. These diverse functions include providing precursors for the biosynthesis of macromolecules, controlling redox status and antioxidant systems, and serving as substrates for post-translational and epigenetic modifications. This functional diversity has sparked great interest in targeting non-essential amino acid metabolism for cancer therapy and has motivated the development of several therapies that are either already used in the clinic or are currently in clinical trials. In this review, we will discuss the important roles that each of the 11 non-essential amino acids play in cancer, how their metabolic pathways are linked, and how researchers are working to overcome the unique challenges of targeting non-essential amino acid metabolism for cancer therapy.

The uptake of amino acids by mouse cells (strain LS) during growth in batch culture and chemostat culture: the influence of cell growth rate

1967 ◽  
Vol 168 (1013) ◽  
pp. 421-438 ◽  
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Amino Acid ◽  
Cell Growth ◽  
Glutamic Acid ◽  
Batch Culture ◽  
Amino Acid Uptake ◽  
Essential Amino Acids ◽  
Growth Yields ◽  
Acid Uptake

The uptake of thirteen essential amino acids by mouse LS cells in suspension culture was determined by bacteriological assay methods. Chemostat continuous-flow cultures were used to determine the effect of different cell growth rates on the quantitative amino acid requirements for growth. The growth yields of the cells ( Y = g cell dry weight produced/g amino acid utilized) were calculated for each of the essential amino acids. A mixture of the non-essential amino acids, serine, alanine and glycine increased the cell yield from the essential amino acids. The growth yields from nearly all the essential amino acids in batch culture were increased when glutamic acid was substituted for the glutamine in the medium. The growth yields from the amino acids in batch culture were much less at the beginning than at the end of the culture. The highest efficiencies of conversion of amino acids to cell material were obtained by chemostat culture. When glutamic acid largely replaced the glutamine in the medium the conversion of amino acid nitrogen to cell nitrogen was 100 % efficient (that is, the theoretical yield was obtained) at the optimum growth rate (cell doubling time, 43 h). The maximum population density a given amino acid mixture will support can be calculated from the data. It is concluded that in several routinely used tissue culture media the cell growth is limited by the amino acid supply. In batch culture glutamine was wasted by (1) its spontaneous decomposition to pyrrolidone carboxylic acid and ammonia, and (2) its enzymic breakdown to glutamic acid and ammonia, but also glutamine was used less efficiently than glutamic acid. Study of the influence of cell growth rate on amino acid uptake rates per unit mass of cells indicated that a marked change in amino acid metabolism occurred at a specific growth rate of 0.4 day -1 (cell doubling time, 43 h). With decrease in specific growth rate below 0.4 day -1 there was a marked stimulation of amino acid uptake rate per cell and essential amino acids were consumed increasingly for functions other than synthesis of cell material.

scholarly journals Nutritional interventions in sarcopenia: a critical review

2015 ◽  
Vol 74 (4) ◽  
pp. 378-386 ◽  
Author(s):  
Mary Hickson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Muscle Mass ◽  
Essential Amino Acid ◽  
Essential Amino Acids ◽  
Protein Supplementation ◽  
Nutrition Intervention ◽  
Nutritional Interventions ◽  
Intervention Trials ◽  
Nutritional Studies

The aim of the present paper is to critically review the details of the published nutrition intervention trials, with and without exercise, targeting sarcopenia. Sarcopenia is the loss of muscle mass, strength and/or performance with age. Since amino acids and energy are required for muscle synthesis it is possible that nutritional intake influences sarcopenia. Nutritional studies are challenging to carry out because of the complexity of modulating dietary intake. It is very difficult to change one nutrient without influencing many others, which means that many of the published studies are problematic to interpret. The studies included evaluate whole protein, essential amino acids and β-hydroxyl β-methylbutyrate (HMB). Whole-protein supplementation failed to show a consistent effect on muscle mass, strength or function. This can be explained by the variations in study design, composition of the protein supplement and the failure to monitor voluntary food intake, adherence and baseline nutritional status. Essential amino-acid supplements showed an inconsistent effect but there are only two trials that have significant differences in methodology and the supplement used. The HMB studies are suggestive of a beneficial effect on older adults, but larger well-controlled studies are required that measure outcomes relevant to sarcopenia, ideally in sarcopenic populations. The issues of timing and distribution of protein intake, and increased splanchnic amino-acid sequestration are discussed, and recommendations for future trials are made.

Nutrition of the bacon pig. XIX. The requirement of the bacon pig for certain essential amino acids

1958 ◽  
Vol 50 (2) ◽  
pp. 230-242 ◽  
Author(s):  
R. E. Evans
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Energy Supply ◽  
Essential Amino Acids ◽  
Food Utilization ◽  
Biological Value ◽  
Potential Value ◽  
The Past

The addition of essential amino acids to all-vegetable diets, so as to raise the biological value of their proteins to the level of animal-protein concentrates, has often been advocated in the past by animal nutritionists. This aim was frustrated in practice since it was impossible, until recently, to secure the necessary supplies at prices that would make such additions economical. Feeding stuffs with added amino acids are now being sold commercially. This is possible following the manufacture of synthetic DL-methionine and crude L-lysine monochloride.It seemed desirable, therefore, to carry out investigations into the potential value of these amino acids to the pig feeder. This paper deals with the effect on growth, food utilization and retention of nitrogen of adding small amounts of lysine and methionine to the diet. An attempt is made to correlate the amino acid composition of the pig's diet with its rate of growth, the energy supply being adequate.

scholarly journals TOLERANCE TO AMINO ACID MIXTURES AND CASEIN DIGESTS GIVEN INTRAVENOUSLY

1945 ◽  
Vol 81 (5) ◽  
pp. 439-448 ◽  
Author(s):  
S. C. Madden ◽  
R. R. Woods ◽  
F. W. Shull ◽  
J. H. Remington ◽  
G. H. Whipple
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Acid Content ◽  
Essential Amino Acids ◽  
Daily Injection ◽  
Nitrogen Requirement ◽  
Amino Acid Mixtures ◽  
Nitrogen Rates ◽  
Crystalline Amino Acids

Several synthetic mixtures of natural and racemic crystalline amino acids suitable for the daily nitrogen requirement are tested in dogs for their tolerance upon intravenous injection. Certain mixtures of the ten essential amino acids plus non-essential amino acids exclusive of glutamic acid are accepted without any obvious sign of disturbance even at rates above 10 mg. nitrogen per kilo per minute for quantities greater than 300 mg. per kilo. One such mixture consists in parts per 100 of dl-threonine 7, dl-valine 15, l(-)-leucine 10.9, dl-isoleucine 9.9, l(+)-lysine· HCl·H2O 10.9, dl-tryptophane 3, dl-phenylalanine 9.9, dl-methionine 6, l(+)-histidine·HCl·H2O 5, l(+)-arginine-HCl 5, glycine 9.9, dl-α-alanine 4, dl-serine 2, l(-)-cystine 0.5, and l(-)-tyrosine 1. In addition other well tolerated mixtures included the prolines. When glutamic acid, natural or racemic, is included in similar mixtures vomiting reactions frequently occur at nitrogen rates above 4 mg. per kilo per minute. Vomiting almost always occurs on the first daily injection containing glutamic acid and usually on any subsequent injection containing more than 100 mg. glutamic acid per kilo unless given very slowly. Upon the addition of glycine certain mixtures of the ten essential amino acids show an improved tolerance. Two casein digests tested usually produced vomiting at injection rates above 2 mg. nitrogen per kilo per minute, probably because of their glutamic acid content. No serious reaction has ever occurrred to any mixture of amino acids or casein digest tested. Elimination of minor reactions such as vomiting appears possible and desirable for greater usefulness of these solutions in parenteral feeding.

EFFECT OF STEAM PELLETING AND REGRINDING ON THE DIGESTIBILITY OF PROTEIN IN CEREAL GRAINS, SOYBEAN MEAL AND WHEAT BRAN BY THE RAT

1968 ◽  
Vol 48 (1) ◽  
pp. 35-39 ◽  
Author(s):  
E. M. Olsen ◽  
S. J. Slinger
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Wheat Bran ◽  
Soybean Meal ◽  
Protein Digestibility ◽  
Essential Amino Acids ◽  
Cereal Grains ◽  
Protein Utilization ◽  
Amino Acid Availability ◽  
Net Protein

The effect if steam pelleting and regrinding on digestibility of protein in corn, wheat, barley, oats, soybean meal and wheat bran was tested with rats. Percentage amino acid absorption and net protein utilization (NPU) were determined for the wheat bran. Pelleting and regrinding improved the digestibility of protein in bran but had no effect on the digestibility of protein in the other ingredients tested. Increased absorption of amino acids caused by the increased digestibility of protein in bran varied considerably for individual amino acids, being greatest for isoleucine, lysine, methionine and threonine of the essential amino acids. The improvement in protein digestibility and amino acid availability was reflected in a higher NPU.

scholarly journals Symbiotic bacteria enable insect to use a nutritionally inadequate diet

2008 ◽  
Vol 276 (1658) ◽  
pp. 987-991 ◽  
Author(s):  
E Akman Gündüz ◽  
A.E Douglas
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Essential Amino Acid ◽  
Acyrthosiphon Pisum ◽  
Amino Acid Content ◽  
Symbiotic Bacterium ◽  
Essential Amino Acids ◽  
Symbiotic Bacteria ◽  
Protein Amino Acid ◽  
Phloem Sap

Animals generally require a dietary supply of various nutrients (vitamins, essential amino acids, etc.) because their biosynthetic capabilities are limited. The capacity of aphids to use plant phloem sap, with low essential amino acid content, has been attributed to their symbiotic bacteria, Buchnera aphidicola , which can synthesize these nutrients; but this has not been demonstrated empirically. We demonstrate here that phloem sap obtained from the severed stylets of pea aphids Acyrthosiphon pisum feeding on Vicia faba plants generally provided inadequate amounts of at least one essential amino acid to support aphid growth. Complementary analyses using aphids reared on chemically defined diets with each amino acid individually omitted revealed that the capacity of the symbiotic bacterium B. aphidicola to synthesize essential amino acids exceeded the dietary deficit of all phloem amino acids except methionine. It is proposed that this shortfall of methionine was met by aphid usage of the non-protein amino acid 5-methylmethionine in the phloem sap. This study provides the first quantitative demonstration that bacterial symbiosis can meet the nutritional demand of plant-reared aphids. It shows how symbiosis with micro-organisms has enabled this group of animals to escape from the constraint of requiring a balanced dietary supply of amino acids.

Use of protein sources alternative to fish meal in diets with amino acids supplementation for the European eel (Anguilla anguilla)

1998 ◽  
Vol 66 (1) ◽  
pp. 285-292 ◽  
Author(s):  
M. García-Gallego ◽  
H. Akharbach ◽  
M. de la Higuera
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Essential Amino Acid ◽  
Fish Meal ◽  
Anguilla Anguilla ◽  
Essential Amino Acids ◽  
Protein Source ◽  
European Eel ◽  
Protein Sources ◽  
Meat Meal

AbstractThis experiment was conducted to test two different protein sources as alternatives to the commonly used fish meal (FM) in the diet of the European eel (Anguilla anguilla). Six experimental diets were tested in three replicated lots of European eels. All diets contained the same protein and energy content (ca, 300 g crude protein per kg dry matter and 18·5 MJ/kg, respectively) but differed in the nature of the protein source: FM was the only protein source in the control diet and was fully or partially (0–5: 0–5) replaced by meat meal (MM) or sunflower meal (SFM) in four other diets; a sixth diet included SFM as the only protein source but was supplemented with several essential amino acids. Food intake, fish growth and several indices of diet and protein utilization were measured. MM clearly was the poorest protein source while SFM could replace, at least 0·5 of the FM with no significant reduction in performance. In addition, the European eel was able to utilize the supplement of essential amino acids. The full-SFM diet was improved significantly when supplemented and results were not statistically different from the control FM-based diet. Overall, a good correlation was found between the results of each diet and the respective essential amino acid index, calculated using as reference the essential amino acid requirements previously defined for another eel species, Anguilla japonica. This index could be used as a reliable measure for an a priori evaluation of alternative protein sources to be included in commercial foods for eels.

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