scholarly journals The effect of dilution of milk proteins with non-essential amino acids (L-alanine and L-glutamic acid) on nitrogen retention and biological value of the proteins in children

1970 ◽  
Vol 24 (3) ◽  
pp. 741-747 ◽  
Author(s):  
V.A. Daniel ◽  
T.R. Doraiswamy ◽  
M. Swaminathan ◽  
D. Rajalakshmi

1. The effect of addition of a mixture of two non-essential amino acids (NEA), namely alanine and glutamic acid, to milk proteins on nitrogen retention and the biological value of the proteins was determined in a group of six girls aged 10–11 years.2. The mean daily intakes of milk protein by the children on three diets (1, 3 and 5 ) were 1.41, 1.10 and 0.70 g/kg body-weight. The quantities of NEA added daily to the three diets were 0.97, 0.49 and 0.97 g/kg body-weight respectively.3. Addition of NEA did not bring about any significant increase in N retention in the children. The addition of NEA to milk proteins significantly decreased the biological value of the proteins.

1969 ◽  
Vol 23 (3) ◽  
pp. 547-557 ◽  
Author(s):  
A. F. Halfpenny ◽  
J. A. F. Rook ◽  
G. H. Smith

1. The plasma levels of individual amino acids were studied in dairy cows under different conditions of production and energy nutrition.2. A preliminary experiment was conducted which established that there was no regular change in amino acid levels with time of sampling in animals offered food twice daily at milking.3. For animals in the 8th month of pregnancy plasma concentrations of lysine, valine, serine and isoleucine were higher, and of threonine lower, in Jersey than in Friesian cows. Lactation was accompanied in most cows by a fall in the plasma concentrations of lysine, arginine, threonine, histidine, glutamic acid, leucine and alanine and a rise in the level of glycine.4. In lactating cows an improvement in the plane of energy nutrition was associated on average with an increase in the plasma concentrations of ‘non-essential’ amino acids and a decrease in the concentrations of ‘essential’ amino acids.5. Intraruminal infusion of propionic acid in the lactating cow increased the concentrations of certain ‘non-essential’ amino acids, glutamic acid in particular, and decreased those of most other ‘essential’ and ‘non-essential’ amino acids.6. These observations are discussed in terms of the possibility that an increased output of amino acids in milk proteins results in a depression in the concentrations of the ‘essential’ and certain of the ‘non-essential’ animo acids in the plasma. The hypothesis is put forward that the plasma supply of the other ‘non-essential’ amino acids, glutamic acid and proline in particular, may limit synthesis of milk proteins.


1979 ◽  
Vol 41 (2) ◽  
pp. 311-319 ◽  
Author(s):  
A. P. Williams ◽  
D. Hewitt

1. Ten calves (50–58 kg live weight) were given a diet consisting of diluted whole milk, wheat gluten and supplemented with appropriate nutrients including amino acids but deficient in lysine. The lysine requirements of these calves, which were growing at approximately 0.25 kg/d, were estimated from responses to lysine supplementation of this diet. From plasma urea, plasma lysine, nitrogen retention and apparent digestibility of N responses the estimated lysine requirements were 8.5, 7.5, 7.2 and 7.6 g/d respectively.2. From the mean lysine requirement (7.8 g/d) and the ratio, lysine: other essential amino acids in carcasses of similar calves the estimated requirements were (g/d): methionine 2.1, cystine 1.6, threonine 4.9, valine 4.8, isoleucine 3.4, leucine 8.4, tyrosine 3.0, phenylalanine 4.4, histidine 3.0, arginine 8.5, tryptophan 1.0.


1990 ◽  
Vol 64 (3) ◽  
pp. 653-661 ◽  
Author(s):  
J. Heger

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.


1967 ◽  
Vol 21 (3) ◽  
pp. 661-670 ◽  
Author(s):  
John H. Ashley ◽  
Hans Fisher

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.


2017 ◽  
Vol 68 (5) ◽  
pp. 1063-1069
Author(s):  
Cristina Simeanu ◽  
Daniel Simeanu ◽  
Anca Popa ◽  
Alexandru Usturoi ◽  
Dan Bodescu ◽  
...  

Polyodon spathula sturgeon breed is successfully reared in Romania in many fishery farms for meat production and it is capitalized on domestic market as consumption fish. In the current paper were studied a number of 1400 sturgeons from Polyodon spathula breed (1200 individuals of one summer - P.s.0+ and 200 individuals of fourth summers - P.s.3+). From this flock were weighted around 10%, for each age group, and for laboratory determinations were chosen 10 fishes for each age with the corporal mass close to the group mean. After analysing the fillets gathered from the studied fishes for establishing the chemical characteristics, nutritive and biological values of proteins were drawn some interesting conclusions. So, regarding chemical composition we notice that in the meat of analysed fishes water is in a rate of 75.41% at P.s.3+ and 78.37% for P.s.0+; proteins - between 18.08% for P.s.0+ and 19.89% for P.s.3+, values which place those fishes in the group of protein fishes; lipids - between 2.45% and 3.45%, values which situated those sturgeons in category of fishes with a low content in lipids; collagen � 3.83% at P.s.0+ and 4.14% at P.s.3+ which indicate low values for proteins of weak quality in the meat of those sturgeons. Study of nutritive value for the analysed fishes indicate the fact that fishes P.s.0+ have a mediocre nutritive value, having the ratio w/p of 4.33 while sturgeons P.s.3+ were placed in the 2nd category � fishes with a good nutritive value (rate w/p = 3.79). Energetic value of the studied fillets was 97.39 kcal/100 g for P.s.0+ and 114.31 kcal/100 g for P.s.3+, which enlightened an increase of nutritive value with aging, fact especially due to accumulation of adipose tissue. Study of proteins quality, through the presence of those 8 essential amino-acids in the meat of analysed fishes, show the fact that at sturgeons P.s.0+ proportion of essential amino-acids was 20.88% from total amino-acids, while at sturgeons P.s.3+ was 26.23%, fact which enlightened an increasing of proteins� biological value with fish aging. This fact was also shown by calculation of proteins� biological value through chemical methods (EAA index); calculated value for sturgeons P.s.0+ was a little bit lower (118.73) than the one calculated for sturgeons P.s.3+ (118.79).


1991 ◽  
Vol 71 (1) ◽  
pp. 211-220 ◽  
Author(s):  
John D. Summers ◽  
J. L. Atkinson ◽  
D. Spratt

Pullets were brought into production on a low-protein corn, soybean meal diet to which various nutrients including essential amino acids, choline, corn oil and feathermeal were supplemented. Production commenced between 18 and 20 wk of age and up to at least 60% production, hens fed the low protein diets (10% CP) produced at least as many eggs and as great an egg mass as these given a 17% protein corn, soybean meal control diet. Pullets fed the corn, soybean meal test diets, peaked at around 80% as compared to slightly over 90% for the control. Egg production immediately fell for birds fed the test diets to around 70% for most of the test treatments. Body weight remained constant or fell after peak production for birds fed the test diets as compared to a normal increase for birds on the control diet. Egg size increased for the test diets at a rate which was comparable to that of the control birds. In a second experiment, with older hens, supplementation of the 10% protein test diet with methionine, lysine, arginine and tryptophan, resulted in intakes of these amino acids which met NRC minimum requirement levels. However, egg mass output was reduced approximately 11% compared to the 17% protein control diet. While intakes of several essential amino acids fell below requirement levels, the degree that valine was calculated to be deficient in both experiments corresponded closely with the reduction in egg mass output of hens fed the test as compared to the control diet. Key words: Lysine, methionine, egg weight, body weight, hens.


1967 ◽  
Vol 168 (1013) ◽  
pp. 421-438 ◽  

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.


Author(s):  
Iyad Ali ◽  
Naser Shraim ◽  
Wafaa’ Atrash ◽  
Aisha Sirafi ◽  
Huda Abadi

Artificial Sweeteners (AS) are synthetic sugar substitutes that have sweetening potency hundreds of times more than the table sugar (sucrose). Artificial sweeteners are regarded as attractive alternatives to sugar as they add no calories to food intake. There are many hypotheses suggesting that AS may enhance appetite and cause weight gain. The aim of this study was to evaluate the effect of AS on food intake, fluid intake and body weight of mice. Acceptable daily intakes of AS solutions were administered orally to different set of mice for four weeks. The body weight, food consumption and fluid intake were measured. At the same time, the effect of Zingiber officinale extracts (natural appetite suppressor), Thymus vulgaris extracts (natural appetite inducer) and cyproheptadine (an appetite stimulant drug) on body weight of mice was evaluated. Artificial sweeteners consumption cause insignificant changes in body weight (p>0.05). However, the mean consumption of food and solutions varies significantly for some groups. The consumption of AS has no significant effect on body weight and may contribute to weight maintenance and energy balance as substitutes to high caloric sugar


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