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.

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.

Plasma essential amino acids concentrations of early lactating Holstein dairy cows fed diet containing raw or roasted Iranian soybean

2007 ◽  
Vol 2007 ◽  
pp. 182-182
Author(s):  
Forouzan Tabatabaie ◽  
Hassan Fathi ◽  
Mohsen Danesh
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Dairy Cows ◽  
Physical Method ◽  
Essential Amino Acids ◽  
High Energy ◽  
Early Lactation ◽  
High Amino Acid ◽  
Amino Acid Requirements ◽  
Physical Treatments

Whole soybean has 40-42 percent CP and used as high energy-protein supplement for early lactation dairy cows. However, the protein is highly degradable, so small amounts of amino acids can be reached to small intestine to meet high amino acid requirements of early lactating cows. Therefore, various chemical and physical treatments have been suggested to decrease ruminal protein degradability of soybeans. The practical use and application of any one method to lower ruminal feed degradability is dependent not only on its efficacy but also on its cost effectiveness, safety and ease of application. For these reasons, heat treatment is the most commonly used physical method (Plegge et al., 1985). The purpose of this study was to determine how roasting of soybeans affect plasma essential amino acid concentrations in early lactation cows.

Amino Acid Requirements of Children: Nitrogen Balance at the Minimal Level of Essential Amino Acids

1964 ◽  
Vol 83 (2) ◽  
pp. 115-118 ◽  
Author(s):  
Itsiro Nakagawa ◽  
Tetsuzo Takahashi ◽  
Takeshi Suzuki ◽  
Katsumi Kobayashi
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nitrogen Balance ◽  
Essential Amino Acids ◽  
Minimal Level ◽  
Amino Acid Requirements

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 Response of adult rats to deficiencies of different essential amino acids

1974 ◽  
Vol 31 (1) ◽  
pp. 47-57 ◽  
Author(s):  
A. K. Said ◽  
D. M. Hegsted ◽  
K. C. Hayes
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nutritive Value ◽  
Plasma Concentrations ◽  
Essential Amino Acids ◽  
The Body ◽  
Adult Rats ◽  
Short Period ◽  
Body Weights ◽  
Fatty Livers

1. Adult rats were fed on diets free of either lysine, methionine, threonine or protein. The threonine- and protein-deficient animals lost weight at approximately the same rate, about 100 g in 14 weeks, at which time several were moribund. In contrast, lysine-deficient animals lost only about 30 g in 14 weeks and had lost only 46 g after 22 weeks, when they were killed. Methionine-deficient animals showed an intermediate response. Losses in weight of several tissues – kidney, heart and two muscles – were related to, but not necessarily proportional to, the loss of body-weight. Liver weights relative to body-weights were large in lysine- and threonine-deficient animals and smallest in methionine-deficient animals.2. Adult rats were fed on diets containing zero, a moderate amount (about twice the estimated minimal requirement) or an excess (about four times the estimated requirement) of lysine or threonine in all combinations (3 × 3 design). Analysis of variance of the body-weights, tissue weights and tissue nitrogen contents indicated, in general, a significant effect of each amino acid, as expected, but also, in most instances, a significant interaction. Plasma concentrations of lysine and threonine were affected by the intakes of the respective amino acids, but plasma lysine concentrations were also affected by the threonine intake.3. Liver histology also suggested significant interactions between the two amino acids. Animals given no lysine but moderate amounts of threonine developed severely fatty livers; next most severely affected were animals receiving excess of both amino acids. Threonine deficiency, in the presence or absence of lysine, produced moderately fatty livers similar to those seen in protein-deficient animals.4. Since animals have varying ability to conserve body nitrogen when they are fed on diets limiting in different essential amino acids, measurements of biological value (BV) and net protein utilization by conventional methods, over a short period of time, over-estimate nutritive value relative to amino acid score and probably over-estimate the true nutritive value of poor-quality proteins, particularly those limiting in lysine. If so, this is a serious error, since it leads to underestimates of the protein requirements if BV is used. The fact that certain tissues, particularly the liver, do not necessarily lose nitrogen in proportion to total body nitrogen and may show specific pathological effects depending on the limiting amino acid or the proportions of amino acids in the diet also indicates that general measures of nitrogen economy may not be sufficiently discriminating tests of the nutritive value of proteins.

The Contribution of Caseins to the Amino Acid Supply for Lactococcus lactis Depends on the Type of Cell Envelope Proteinase

1998 ◽  
Vol 64 (6) ◽  
pp. 1991-1996 ◽  
Author(s):  
Benedicte Flambard ◽  
Sandra Helinck ◽  
Jean Richard ◽  
Vincent Juillard
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Amino Acid ◽  
Lactococcus Lactis ◽  
Cell Envelope ◽  
Essential Amino Acids ◽  
Genetically Engineered ◽  
Amino Acid Requirements ◽  
Rate Limiting

ABSTRACT The ability of caseins to fulfill the amino acid requirements ofLactococcus lactis for growth was studied as a function of the type of cell envelope proteinase (PI versus PIII type). Two genetically engineered strains of L. lactis that differed only in the type of proteinase were grown in chemically defined media containing αs1-, β-, and κ-caseins (alone or in combination) as the sources of amino acids. Casein utilization resulted in limitation of the growth rate, and the extent of this limitation depended on the type of casein and proteinase. Adding different mixtures of essential amino acids to the growth medium made it possible to identify the nature of the limitation. This procedure also made it possible to identify the amino acid deficiency which was growth rate limiting for L. lactis in milk (S. Helinck, J. Richard, and V. Juillard, Appl. Environ. Microbiol. 63:2124–2130, 1997) as a function of the type of proteinase. Our results were compared with results from previous in vitro experiments in which casein degradation by purified proteinases was examined. The results were in agreement only in the case of the PI-type proteinase. Therefore, our results bring into question the validity of the in vitro approach to identification of casein-derived peptides released by a PIII-type proteinase.

Effects of atropine on plasma amino acid profiles and on the synthesis of individual milk proteins in dairy cows fed with pasture

2003 ◽  
Vol 70 (4) ◽  
pp. 373-378 ◽  
Author(s):  
Martin J Auldist ◽  
Catherine M Menzies ◽  
Colin G Prosser
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Blood Plasma ◽  
Latin Square ◽  
Milk Proteins ◽  
Protein Composition ◽  
Essential Amino Acids ◽  
Plasma Amino Acid ◽  
Milk Components ◽  
In Blood Plasma

Effects of atropine on blood plasma amino acid profile and on the yields and concentration of milk components were investigated in 12 Friesian cows in early lactation. Cows were housed indoors and fed with cut pasture ad libitum. Each cow received four treatments over 12 d during a replicated 4×4 Latin square experiment. Treatments were: control (saline); low dose (L; 30 μg atropine/kg body weight (BW)); medium dose (M; 40 μg atropine/kg BW); and 2×L dose, 2 h apart (2×L). On each of four treatment days, cows were milked at about 7.00, after which treatments were administered by subcutaneous injection. Cows were milked again at 2 h, 6 h and 10 h after injection. Milk samples were collected at each milking. Immediately after the 2 h milking, blood samples were drawn from each cow and the second injection was given for the 2×L treatment. Atropine reduced hourly milk yield, and concentrations and hourly yields of total protein, casein, whey protein, α-casein, β-casein, κ-casein, β-lactoglobulin and α-lactalbumin, but by differing amounts. Milk concentrations of bovine serum albumin and immunoglobulin G were increased by atropine, and overall yields of these proteins were mostly unchanged. Atropine lowered concentrations of most, but not all, amino acids in blood plasma, with essential amino acids reduced more than non-essential amino acids. Concentrations of α-amino N in whole blood, and glucose and insulin in blood plasma, fell after atropine injection. There was no difference between the L and M doses of atropine, but the 2×L dose had greater effects on milk composition than the single doses. For yields of milk and milk components, the effect of the 2×L dose was also more persistent. The results highlight the differential synthesis of individual milk proteins, and suggest that atropine might be useful for evaluating the mechanisms regulating milk protein composition.

scholarly journals THE AMINO ACID REQUIREMENTS OF RABBIT FIBROBLASTS, STRAIN RM3-56

1957 ◽  
Vol 41 (1) ◽  
pp. 91-100 ◽  
Author(s):  
R. F. Haff ◽  
H. E. Swim
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Good Condition ◽  
Essential Amino Acids ◽  
The Other ◽  
Isoleucine Leucine ◽  
Cellular Degeneration ◽  
Amino Acid Requirements ◽  
Dialyzed Serum

Strain RM3-56 of rabbit fibroblasts was found to require arginine, cystine, glutamine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, and valine for growth in a medium containing 2 per cent dialyzed serum as the only undefined component. The requirement for serine is less specific than that of the other 13 amino acids and it is partially replaced by glycine, or alanine, or by several combinations of so called accessory amino acids. The concentrations of essential amino acids which permit maximal proliferation range from 0.005 to 0.3 mM. Cystine, glutamine, lysine, tryptophan, tyrosine, valine are toxic at concentrations of 5 mM. The rate of proliferation of RM3-56 in a medium containing all 14 essential amino acids is increased significantly by the addition of alanine and to a lesser extent by the addition of aspartic and glutamic acids and glycine. A deficiency of cystine or glutamine results in cellular degeneration within 3 to 5 days, whereas the cells remain in good condition for 2 to 3 weeks in the absence of each of the remaining 12 essential amino acids. The results obtained with RM3-56 are compared with strains HeLa, L, and U12, whose amino acid requirements have been investigated under similar conditions.

SUBSTITUTION OF CHOLINE BY RELATED COMPOUNDS AND FURTHER STUDIES ON AMINO ACID REQUIREMENTS IN NUTRITION OF PHORMIA REGINA (MEIG.)

1956 ◽  
Vol 34 (6) ◽  
pp. 527-532 ◽  
Author(s):  
Ernest Hodgson ◽  
Vernon H. Cheldelin ◽  
R. W. Newburgh
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Essential Amino Acids ◽  
Phormia Regina ◽  
Acid Growth ◽  
Dietary Requirement ◽  
Amino Acid Requirements ◽  
Related Compounds

Phormia regina grown on a chemically defined diet under sterile conditions has been shown to have a specific dietary requirement for choline. The present work shows that carnitine and 2,2-dimethylaminoethanol can completely replace this in the diet whereas betaine is ineffective in this respect. Deletion of single amino acids from a mixture of 18 adequate for growth has previously shown the following 10 amino acids to be essential: arginine, histidine, leucine, lysine, phenylalanine, threonine, tryptophan, valine, proline, and isoleucine. The present work: shows by the inability of the organism to grow on these essential amino acids that this method is not adequate to detect amino acid combinations for which alternate requirements exist. By the deletion of groups of two or more amino acids it has been shown that P. regina has a dietary requirement for either methionine or cystine and for either glutamic acid or aspartic acid. Growth on the 10 essential amino acids is stimulated by yeast extract. This is apparently not due to a simple replacement of missing amino acids, since the addition of yeast creates an increased requirement for thiamine.

scholarly journals Digestion, absorption and utilization of single-cell protein by the preruminant calf

1985 ◽  
Vol 54 (1) ◽  
pp. 219-244 ◽  
Author(s):  
Cynthia A. Sedgman ◽  
J. H. B. Roy ◽  
Joanne Thomas ◽  
I. J. F. Stobo ◽  
P. Ganderton
Keyword(s):  
Amino Acids ◽  
Small Intestine ◽  
Amino Acid ◽  
Milk Protein ◽  
Alimentary Tract ◽  
Latin Square ◽  
Essential Amino Acids ◽  
Apparent Digestibility ◽  
Bacterial Protein ◽  
True Digestibility

1.Two experiments of Latin square design were made, each with four Friesian bull calves fitted with re-entrant duodenal and ileal cannulas at 4–10 d of age. The calves were used to studythe effect of giving milk-substitutes containing 0, 300, 500 and 700 g bacterial protein (Pruteen)/kg total protein on apparent digestibility of nitrogen fractions and amino acids and true digestibility of 3H-labelled milk protein and 35S-labelled bacterial protein in the small intestine. A third experiment of Latin square design with four intact Friesian calves was used to measure apparent digestibility of nutrients throughout the alimentary tract and retention of N, calcium and phosphorus.2.At the duodenum, volume of outflow, its pH, and outflow of total-N (TN), protein-N (PN) and non-protein-N (NPN) decreased with time after feeding. At the ileum, volume of outflow and TN outflow were unaffected by time after feeding but PN outflow decreased; NPN outflow at the ileum increased to a maximum 6 h after feeding and then declined.3.Increased inclusion of Pruteen did not affect the volume of outflow at the duodenum or ileum, but duodenal PN outflow increased. At the ileum, pH values were lower and TN, PN and NPN outflows were higher with increasing concentration of Pruteen in the diet. Apparent digestibility in the small intestine tended to decrease with greater amounts of Pruteen, but was only significant for NPN. Apparent digestibility from mouth to ileum significantly decreased for TN and PN as Pruteen inclusion increased.4.Amino acid concentration in duodenal outflow, with the exception of that of arginine, reflected intake. The total amount of each amino acid in ileal outflow increased and the apparent digestibility of most amino acids decreased with greater amounts of Pruteen in the diet. Apparent digestibility of nucleic acid-N from Pruteen was very high.5.True digestibility in the small intestine and between mouth and ileum of 3H-labelled milk protein was high and did not differ between dietary treatments. True digestibility of 36S-labelled Pruteen was low for the milk-protein diet and tended to increase linearly as more dietary Pruteen was included.6.Dry matter concentration in faeces and a high apparent digestibility throughout the whole alimentary tract of carbohydrates did not differ between treatments. Apparent digestibility of dry matter, organic matter, crude protein and fat, apparent absorption of Ca, P and ash throughout the tract, retention of N, Ca and P and biological value of the protein decreased with inclusion rates greater than 300 g Pruteen/kg total dietary protein. The amount of N apparently absorbed in the large intestine was estimated as 0.9 g/d.7.Comparison of intake of apparently absorbed essential amino acids with requirement suggests that histidine is likely to be the limiting amino acid, assuming that arginine is synthesized in the body.8.Efficiencies of utilization of protein for tissue synthesis and to cover obligatory loss are estimated as 0.80, 0.75, 0.66 and 0.47 for diets containing 0, 300, 500 and 700 g Pruteen/kg total protein in the diet. Efficiencies of utilization of individual essential amino acids were also estimated.

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