479. Studies on the biological value of the proteins (nitrogen) of dried skim milk: effects of the addition of certain amino-acids, of age of rat and of level of protein intake

1952 ◽  
Vol 19 (2) ◽  
pp. 216-225 ◽  
Author(s):  
K. M. Henry ◽  
S. K. Kon
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Intake ◽  
Skim Milk ◽  
Adult Rats ◽  
Biological Value ◽  
Adult Rat ◽  
Amino Acid Requirements ◽  
Limiting Amino Acid ◽  
Control Milk

1. It has been shown that the biological value of undeteriorated dried skim milk is depressed to the same extent by the addition of 1·25% L-lysine as by the addition of 1·25% D-lysine. The latter is not used by the rat. It is therefore concluded that the added L-lysine is surplus to the animal's needs and that the apparent lowering of the biological value is due to excretion of the lysine in the urine.2. The slightly greater loss in the biological value of milk stored in air-pack compared with gas-pack was eliminated by the addition of 0·5% L-histidine to the former. Histidine is not a limiting amino-acid in the control or stored gas-pack milks for either young or adult rats.3. A lower biological value was found for the control milk with adult than with young rats at 4 and 8% levels of intake. No further lowering in the biological value of the stored milk, deficient in lysine, was observed with adult rats, the value obtained for this milk being independent of the age of the rat. These results are in keeping with the known lowered requirements of the adult rat for lysine.4. The significance of these findings in relation to the known amino-acid requirements of young and adult rats is discussed.

scholarly journals Studies of amino acid requirements of adult rats

1967 ◽  
Vol 21 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Elizabeth B. Smith ◽  
B. C. Johnson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Proteins ◽  
Latin Square ◽  
Essential Amino Acids ◽  
Adult Rats ◽  
Adult Rat ◽  
Amino Acid Requirements ◽  
Series Of Experiments ◽  
Whole Egg

1. A series of experiments was carried out to determine the minimum essential amino acid requirements of the adult rat.2. After testing four amino acid patterns taken from the literature, a basal pattern was formulated in which each amino acid appeared at the lowest level at which it was presented in any of the original diets.3. Nitrogen balance was the main criterion used to judge any benefit arising from modest increases in individual amino acids tested in a modified Latin-square design. They were given at a protein level of 3.6% of the diet. Non-essential amino acids were in the same proportions as in whole egg.4. It appeared that three amino acids, namely tryptophan, threonine and isoleucine, brought about more favourable balances when presented at concentrations higher than basal.5. Reduced levels of each amino acid were then tested in order to ensure that no surpluses were present.6. N retentions indicated that lysine, phenylalanine plus tyrosine, leucine and valine could be reduced below the basal level and still meet the needs of the rat for these amino acids.7. When the pattern of amino acids arising from these latter trials was tested in combination, rather than as trios, pairs, or single changes, positive N balances gave confidence that these were minimal levels of the essential amino acids required for meeting the maintenance needs of adult rats.8. Plasma proteins from the rats on the evolved pattern were found to be in no way different from those found for normal animals. This gave further support to the belief that the pattern was adequate for the rats.

scholarly journals The metabolic utilization of amino acids: potentials of 14CO2 breath test measurements

1992 ◽  
Vol 67 (2) ◽  
pp. 207-214 ◽  
Author(s):  
V. V. A. M. Schreurs ◽  
H. A. Boekholt ◽  
R. E. Koopmanschap ◽  
P. J. M. Weijs
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Breath Test ◽  
Relative Rate ◽  
The Body ◽  
Adult Rats ◽  
Total Oxidation ◽  
Amino Acid Utilization ◽  
Amino Acid Requirements ◽  
14Co2 Breath Test

The present paper offers a dual 14CO2 breath test approach to study the metabolic utilization of free amino acids in the body. Using the carboxyl-[14C]isotopomer of an amino acid as the test substrate the percentage recovery of the isotope as 14CO2 reflects which part of the labelled amino acid flux has been decarboxylated. The residual C fragments may flow to total oxidation at least to the level recovered for the universal [14C]isotopomer. In the case that recovery for total oxidation is less than for decarboxylation, part of the [14C]fragments are retained in the body by either exchange or non-oxidative pathways. Utilization of tyrosine and leucine was measured in the post-absorptive phase in adult rats conditioned on isoenergetic diets containing 210, 75 or 0 g protein/kg. It was shown that the level of dietary protein exerts an influence on both decarboxylation and total oxidation. Although the responses of leucine and tyrosine were not different for total oxidation, there was a difference between the amino acids in their relative rate of decarboxylation. That this dual 14CO2 breath test approach can be used as a tool to evaluate whether the protein and amino acid supply has been adequate to support actual requirements is discussed.Amino acid utilization: Amino acid requirements: Leucine: Tyrosine

scholarly journals Oxidation of an indicator amino acid by young pigs receiving diets with varying levels of lysine or threonine, and an assessment of amino acid requirements

1983 ◽  
Vol 50 (2) ◽  
pp. 391-399 ◽  
Author(s):  
Kyu-Il Kim ◽  
James I. Elliott ◽  
Henry S. Bayley
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino ◽  
Skim Milk ◽  
Linear Increase ◽  
Single Amino Acid ◽  
Dietary Level ◽  
Dietary Amino Acids ◽  
Young Pigs ◽  
Amino Acid Requirements

1. The catabolism of [14C]phenylalanine was used to indicate the effects of varying the dietary level of lysine and threonine on the retention of dietary amino acids by 2-week-old pigs receiving diets containing skim milk and a mixture of free amino acids.2. Reducing the dietary level of lysine from 16 to 12 g/kg had no influence on phenylalanine oxidation, reducing the lysine level from 12 to 11 then to 10 g/kg caused an almost linear increase in phenylalanine oxidation whereas further reduction to 9 or 8 g/kg resulted in a less-marked increase in phenylalanine oxidation. This showed that 12 g lysine/kg was required to maximize amino acid retention and indicated that lysine was conserved more effectively at low dietary concentrations than at dietary concentrations approaching the requirement.3. Reducing the dietary level of threonine from 8 to 6 g/kg had no influence on phenylalanine oxidation, whereas further reduction to 4 g/kg caused a linear increase in phenylalanine catabolism showing that 6 g threonine/kg was required to maximize amino acid retention.4. Reduction of the levels of lysine, threonine and methionine from the generous levels characteristic of a diet containing 240 g protein from skim milk/kg, to the requirement levels determined separately in the presence of the generous levels of all the other amino acids, resulted in a twofold increase in phenylalanine catabolism. This shows that the pig seems able to conserve limiting intakes of a single amino acid, but not if the intakes of two or three amino acids are limiting.

scholarly journals The influence of selected cultivation on the content of total protein and amino acids in the potato tubers

2011 ◽  
Vol 49 (No. 3) ◽  
pp. 131-134 ◽  
Author(s):  
J. Mitrus ◽  
C. Stankiewicz ◽  
E. Steć ◽  
M. Kamecki ◽  
J. Starczewski
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Total Protein ◽  
Total Protein Content ◽  
Row Spacing ◽  
Quality Changes ◽  
Potato Tubers ◽  
Biological Value ◽  
Potato Varieties ◽  
Limiting Amino Acid

The aim of study was to determine the effect of selected cultivation operations, such as nitrogenous fertilization (60,90 kgN/ha), row spacing (62, 82,102 cm), compaction of soil with wheels of farm aggregates (the numbers of passing 2×, 5×, 8×), on quality changes of two potato varieties (Irga and Ekra). The total protein content in the tubers of the tested potato varieties increased with the increase of the nitrogenous fertilization (90 kgN/ha). Genotype features of the tested potato tubers define the amino acid limiting the protein biological value (CS) to be leucine in Irga variety and isoleucine in Ekra variety. It is also genotype that influences the second limiting amino acid. It is the sum of sulphuric amino acids (Cys + Met) in respect to Irga variety and valine in respect to Ekra variety. The dose of90 kgN/ha decreases the protein biological value (EAAI) of the tubers of Ekra variety, which is high in starch.

scholarly journals The nutritional value of plant-based diets in relation to human amino acid and protein requirements

1999 ◽  
Vol 58 (2) ◽  
pp. 249-260 ◽  
Author(s):  
D. Joe Millward
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Human Subjects ◽  
Human Growth ◽  
Amino Acid Pattern ◽  
World Health ◽  
Biological Value ◽  
Protein Requirements ◽  
Age Related ◽  
Amino Acid Requirements

The adequacy of plant-based diets in developed and developing countries as sources of protein and amino acids for human subjects of all ages is examined. Protein quantity is shown not to be an issue. Digestibility is identified as a problem for some cereals (millet (Panicum miliaceum) and sorghum (Sorghum sp.)) and generally is poorly understood. Direct measurements of biological value in children are reviewed and scoring is consid-ered. Various existing requirement values for amino acids and especially lysine are reviewed, and it is concluded that stable-isotope studies do not yet provide adequate alternative values to N balance data, which for lysine are robust after recalculation and adjustment. A new maintenance requirement pattern is developed, with higher values than those of Food and Agriculture Organization/World Health Organization/United Nations University (1985) but lower values than the Massachusetts Institute of Technol-ogy pattern (Young et al. 1989). Calculations of age-related amino acid requirements are based on most recent estimates of human growth and maintenance protein requirements, a tissue amino acid pattern and the new maintenance amino acid pattern. These values appear valid when used to score plant proteins, since they indicate values similar to or less than the biological value measured directly in young children. When used to score plant-based diets in India, no marked deficiencies are identified. All regions score > 1 for adults, whilst for children scores range from > 1, (Tamil Nadhu) from 6 months of age to 0.78 (West Bengal), rising to 0.9 in the 2–5 year old, consistent with reports that high-lysine maize supports similar weight and height growth to that of casein. Inadequate amino acid supply is not an issue with most cereal-based diets.

scholarly journals Amino Acid Profiles of the Flesh of the Heterosexual Pairs of Neopetrolisthes maculatus

2017 ◽  
Vol 61 ◽  
pp. 23-35 ◽  
Author(s):  
Emmanuel Ilesanmi Adeyeye
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Essential Amino Acid ◽  
Essential Amino Acids ◽  
Efficiency Ratio ◽  
Amino Acids Composition ◽  
Amino Acid Requirements ◽  
Amino Acid Profiles ◽  
Limiting Amino Acid ◽  
Acid Index

This paper reports on amino acid profiles of the flesh of heterosexuals of porcellanids collected from the Atlantic Ocean at Orimedu beach in Ibeju-Lekki, Lagos, Nigeria. Results showed that high values of amino acids were observed in the heterosexual flesh of Neopetrolisthes maculatus (g 100g-1 protein): 17.7 – 17.8 (Glu), 9.90 – 10.0 (Asp), 8.70 – 9.07 (Arg), 7.23 – 7.94 (Leu) and 5.81 – 6.06 (Gly). Total essential amino acid values ranged from 45.2 – 46.2 g 100-1g. Predicted protein efficiency ratio was 3.82 – 4.14, the range of essential amino acid index was 86.9 – 89.9, the biological values ranged from 83.0 – 86.3. The Lys/Trp was 3.31-4.27. Serine was limiting amino acid (0.513 – 0.516) in the egg score comparison; under the essential amino acids scores, Lys (0.840) was limiting in female but Val (0.823) was limiting in the male; Lys (0.796 – 0.905) was limiting in both samples in the pre-school child amino acid requirements. It was observed that out of the twenty parameters determined, male flesh was more concentrated in 60% values than the female flesh and 40% better in female than male. Correlation coefficient result showed that significant differences existed in the amino acids composition at r = 0.01 of the N. maculatus samples.

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

Effect of Intraduodenal Starch Infusion on Net Portal Absorption of Amino Acids in Growing steers Fed Lucerne

1994 ◽  
Vol 1994 ◽  
pp. 28-28
Author(s):  
C.J. Seal ◽  
D.S. Parker ◽  
J.C. MacRae ◽  
G.E. Lobley
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Gastrointestinal Tract ◽  
Protein Turnover ◽  
Portal Blood ◽  
Intestinal Lumen ◽  
Short Term ◽  
Net Uptake ◽  
Amino Acid Requirements ◽  
Glucose Availability

Amino acid requirements for energy metabolism and protein turnover within the gastrointestinal tract are substantial and may be met from luminal and arterial pools of amino acids. Several studies have demonstrated that the quantity of amino acids appearing in the portal blood does not balance apparent disappearance from the intestinal lumen and that changing diet or the availability of energy-yielding substrates to the gut tissues may influence the uptake of amino acids into the portal blood (Seal & Reynolds, 1993). For example, increased net absorption of amino acids was observed in animals receiving exogenous intraruminal propionate (Seal & Parker, 1991) and this was accompanied by changes in glucose utilisation by the gut tissues. In contrast, there was no apparent change in net uptake of [l-13C]-leucine into the portal vein of sheep receiving short term intraduodenal infusions of glucose (Piccioli Cappelli et al, 1993). This experiment was designed to further investigate the effects on amino acid absorption of changing glucose availability to the gut with short term (seven hours) or prolonged (three days) exposure to starch infused directly into the duodenum.

Amino acids in blood plasma and tissues of rats following glucose force-feeding

1969 ◽  
Vol 47 (3) ◽  
pp. 323-327 ◽  
Author(s):  
J. E. Knipfel ◽  
H. G. Botting ◽  
F. J. Noel ◽  
J. M. McLaughlan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Blood Plasma ◽  
Protein Composition ◽  
Tissue Uptake ◽  
Body Protein ◽  
Glucose Administration ◽  
Force Feeding ◽  
Amino Acid Requirements ◽  
Concentration Changes

Changes in plasma amino acid (PAA) concentrations effected by force-feeding glucose to rats were studied in two experiments. Attempts were made to relate PAA concentration changes to amino acid requirements, previous diet, time after feeding glucose, and composition of several body proteins. Distribution of 14C-lysine between blood and tissues was examined in an additional rat experiment. Previous diet did not affect the relative quantities of amino acids removed from plasma (PAA removal pattern) after glucose force-feeding. Minimal PAA concentrations occurred by 40 min after glucose administration. The PAA removal pattern was not distinctly related to either amino acid requirements or to any particular body protein composition. Results of administering 14C-lysine simultaneously with glucose indicated that decreased plasma 14C-lysine levels were caused by increased tissue uptake of 14C, likely mediated by insulin. Muscle acted as the major recipient of 14C from plasma, with liver a lesser and more dynamic reservoir of 14C accumulation. Work is continuing to further clarify the significance of the PAA removal pattern, caused by the force-feeding of glucose.

Whole-body leucine and lysine metabolism: response to dietary protein intake in young men

1981 ◽  
Vol 240 (6) ◽  
pp. E712-E721 ◽  
Author(s):  
K. J. Motil ◽  
D. E. Matthews ◽  
D. M. Bier ◽  
J. F. Burke ◽  
H. N. Munro ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dietary Protein ◽  
Protein Intake ◽  
Whole Body ◽  
Dietary Protein Intake ◽  
Body Protein ◽  
Fed State ◽  
Amino Acid Requirements ◽  
Maintenance Requirements ◽  
Lysine Metabolism

Whole-body leucine and lysine metabolism was explored in young adult men by a primed constant intravenous infusion of a mixture of L-[1–13C]leucine and L-[alpha-15N]lysine over a 4-h period. Subjects were studied after an overnight fast (postabsorptive state) or while consuming hourly meals (fed state) after adaptation to diets providing either a surfeit level of protein (1.5 g.kg body-1.day-1), a level approximating maintenance requirements (marginal intake) (0.6 g.kg body wt-1.day-1), or a grossly inadequate level (0.1 g.kg-1.day-1). The change in protein intake from a marginal to a surfeit level was associated with an increased leucine flux and incorporation of leucine into body protein. In the fed state, oxidation of leucine increased sharply and release of leucine from tissue protein diminished. When dietary protein intake was reduced from the requirement to inadequate level, leucine flux and body protein synthesis and protein breakdown were reduced, together with a smaller reduction in leucine oxidation. The response of the metabolism of [15N]lysine was responsible for maintenance of leucine and other essential amino acid economy, and they appear to be related to the nitrogen and amino acid requirements of the subject. These findings also demonstrate an effect of meals, modulated by their protein content, on the dynamics of whole-body amino acid metabolism.

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