scholarly journals Protein Substitutes in PKU; Their Historical Evolution

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 484
Author(s):  
Anne Daly ◽  
Sharon Evans ◽  
Alex Pinto ◽  
Catherine Ashmore ◽  
Anita MacDonald
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Animal Studies ◽  
Slow Release ◽  
Physiological Function ◽  
Nitrogen Retention ◽  
Gut Health ◽  
Physiological Profile ◽  
Potential Benefits ◽  
Normal Physiological Function

Protein substitutes developed for phenylketonuria (PKU) are a synthetic source of protein commonly based on L-amino acids. They are essential in the treatment of phenylketonuria (PKU) and other amino acid disorders, allowing the antagonistic amino acid to be removed but with the safe provision of all other amino acids necessary for maintaining normal physiological function. They were first formulated by a chemist and used experimentally on a 2-year-old girl with PKU and their nutritional formulations and design have improved over time. Since 2008, a bioactive macropeptide has been used as a base for protein substitutes in PKU, with potential benefits of improved bone and gut health, nitrogen retention, and blood phenylalanine control. In 2018, animal studies showed that physiomimic technology coating the amino acids with a polymer allows a slow release of amino acids with an improved physiological profile. History has shown that in PKU, the protein substitute’s efficacy is determined by its nutritional profile, amino acid composition, dose, timing, distribution, and an adequate energy intake. Protein substitutes are often given little importance, yet their pharmacological actions and clinical benefit are pivotal when managing PKU.

scholarly journals Regulation of rat magnocellular neurosecretory system by D-aspartate: evidence for biological role(s) of a naturally occurring free D-amino acid in mammals

2000 ◽  
Vol 167 (2) ◽  
pp. 247-252 ◽  
Author(s):  
H Wang ◽  
H Wolosker ◽  
J Pevsner ◽  
SH Snyder ◽  
DJ Selkoe
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Amino Acid ◽  
Physiological Function ◽  
Neurosecretory System ◽  
Milk Ejection ◽  
Magnocellular Neurons ◽  
Rat Hypothalamus ◽  
Naturally Occurring

Little evidence is available for the physiological function of D-amino acids in species other than bacteria. Here we demonstrate that naturally occurring freed -aspartate (D-Asp) is present in all magnocellular neurons of rat hypothalamus. The levels of this naturally occurring D-amino acid were elevated during lactation and returned to normal thereafter in the magnocellular neurosecretory system, which produces oxytocin, a hormone responsible for milk ejection during lactation. Intraperitoneal injections of D-Asp reproducibly increased oxytocin gene expression and decreased the concentration of circulating oxytocin in vivo. Similar changes were observed in the vasopressin system. These results provide evidence for the role(s) of naturally occurring free D-Asp in mammalian physiology. The findings argue against the conventional concept that only L-stereoisomers of amino acids are functional in higher species.

An optimal dietary amino acid pattern for growing pigs

1997 ◽  
Vol 1987 ◽  
pp. 91-91 ◽  
Author(s):  
T. C. Wang ◽  
M. F. Fuller
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nitrogen Retention ◽  
Essential Amino Acids ◽  
Growing Pigs ◽  
Amino Acid Pattern ◽  
Dietary Amino Acid ◽  
Ideal Protein ◽  
Limiting Amino Acid ◽  
The Ideal

An animal's rate of protein accretion (or nitrogen retention) is determined by the most deficient (or first limiting) amino acid in the diet, in a perfectly balanced (or ideal) protein all essential amino acids and the sum of the non-essential amino acids are equally limiting. If a dietary protein had any amino acids in excess of the ideal pattern, then the removal of any of the excess should not affect nitrogen retention. This principle was used to determine the ideal dietary amino acid pattern for growing pigs.Three nitrogen balance trials were carried out with a total of 64 gilts of weight from 30 to 55 kg. Casein and a mixture of amino acids were used in the semi-purified diets. The animals were given the diets at the rate of 93 g/kg BW0.75/d in three equal meals mixed with 0.3 L water. The feeding times were 08.30, 12.30 and 17.30. All pigs received their experimental diets for 7 days, made up of 3 days preliminary and a 4-day collection, except that the preliminary period before the first collection in the first period was 7 days. Before the first collection bladder catheters were introduced.

Amino Acid Profile and Aromatic Amino Acid Concentration in Total Parenteral Nutrition: Effect on Growth, Protein Metabolism and Aromatic Amino Acid Metabolism in the Neonatal Piglet

1994 ◽  
Vol 87 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Linda J. Wykes ◽  
James D. House ◽  
Ronald O. Ball ◽  
Paul B. Pencharz
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Parenteral Nutrition ◽  
Human Milk ◽  
Total Parenteral Nutrition ◽  
Aromatic Amino Acid ◽  
Nitrogen Retention ◽  
Aromatic Amino Acids ◽  
The Other ◽  
Constant Infusion

1. The protein and amino acid utilization of two commercially available amino acid solutions, one egg-patterned (Vamin), the other human-milk-patterned (Vaminolact), were studied in piglets receiving total parenteral nutrition. It was hypothesized that Vaminolact was deficient in total aromatic amino acids, so a third group received a human-milk-patterned amino acid solution with added phenylalanine. 2. The piglets were on total parenteral nutrition for 8 days from day 2 or 3 of life. They all received a total energy intake of 1040 kJ day−1 kg−1 with macro-nutrient intakes of 14.6g of amino acid, 27.4 g of glucose and 9.4 g of fat day−1 kg−1. 3. Nitrogen balances were performed on days 3-8 of total parenteral nutrition. On day 8 a primed constant infusion of (1-14C]-phenylalanine was given to measure phenylalanine flux and fractional conversion to tyrosine. Transamination catabolites of phenylalanine and tyrosine were measured in urine on day 7. 4. The piglets receiving Vaminolact gained significantly less weight (0.86 kg compared with 1.18 kg for Vamin and 1.20 kg for phenylalanine-supplemented Vaminolact; P < 0.02) and nitrogen (1435 mg day−1 kg−1 compared with 1601 mg and 1836 mg day−1 kg−1 for the other groups; P < 0.0001). 5. The piglets receiving Vamin had high plasma phenylalanine levels (2234 μmol/l compared with 156 μmol/l for Vaminolact and 399 μmol for phenylalanine-supplemented Vaminolact; P < 0.0001). Those receiving Vamin also had an elevated excretion of phenylalanine transamination metabolites and low plasma lysine levels. Phenylalanine flux was highest in the Vamin group, intermediate in the phenylalanine-supplemented Vaminolact group and lowest in the Vaminolact group. 6. We conclude that Vaminolact is limiting in aromatic amino acids and that the addition of phenylalanine to the level in Vamin significantly improves growth and nitrogen retention; however, increasing the phenylalanine content of total parenteral nutrition is not the most metabolically suitable way to provide aromatic amino acids in neonatal total parenteral nutrition.

scholarly journals Allometric growth of protein, amino acids, fat and minerals in slow- and fast-growing young chickens

2011 ◽  
Vol 56 (No. 3) ◽  
pp. 127-135 ◽  
Author(s):  
J. Zelenka ◽  
J. Heger ◽  
S. Kráčmar ◽  
E. Mrkvicová
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nitrogen Retention ◽  
Growth Period ◽  
The Body ◽  
Allometric Growth ◽  
Retention Efficiency ◽  
Body Protein ◽  
Fast Growing ◽  
Protein Amino Acids

Allometric growth of body constituents and apparent efficiency of amino acid and nitrogen retention were examined in slow-growing laying-type cockerels (SG) and in fast-growing male broiler hybrids (FG) during the growth period from hatch to Day 22. The respective allometric coefficients for water, protein, (N &times; 6.25)ash and fat in relation to body weight were 0.971, 1.080, 1.096 and 1.284 for SG chickens and 0.977, 1.099, 0.993, and 1.198 for FG chickens. The respective allometric coefficients describing the relationships of water, fat and ash weight with protein weight were 0.894, 1.014, and 1.186 for SG chickens and 0.893, 0.910, and 1.097 for FG chickens. High allometric coefficients for ash in both genotypes likely indicate the rapid growth of skeletal tissues which requires adequate mineral nutrition during this period of growth. The deposition of ash relative to protein was significantly higher (P &lt; 0.05) in SG chickens thus suggesting that the relative growth of ash may be affected by genotype. Allometric coefficients relating amino acids to body protein were less than unity in most cases which indicates that an increasing amount of non-protein N is deposited in the body with advancing age. Except for cysteine, the apparent efficiency of amino acid retention was lower in SG as compared to FG chickens. The high retention efficiency of cysteine in SG genotype was likely associated with the conversion of surplus methionine to cysteine, required for feather protein synthesis in laying-type birds at an early age.

scholarly journals The effect of amino acid imbalance on nitrogen retention (biological value) in rats

1981 ◽  
Vol 45 (1) ◽  
pp. 175-181 ◽  
Author(s):  
B. O. Eggum ◽  
K. E. Bach Knudsen ◽  
Ingeborg Jacobsen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nitrogen Retention ◽  
Basal Diet ◽  
Single Amino Acid ◽  
Protein Utilization ◽  
Biological Value ◽  
Egg Protein ◽  
Amino Acid Imbalance ◽  
Barley Protein

1. Three series of nitrogen balance experiments were performed with growing rats to test the effect of amino acid imbalance on protein utilization. In Expt 1 egg protein was fed as a basal diet and supplemented with one amino acid at a time in the amounts originally found in egg protein. In Expt 2 the procedure was repeated with a barley diet, and in Expt 3 egg and potato proteins were fed together in various combinations.2. Doubling the single amino acids, especially arginine, in an egg-protein diet reduced biological value (BV) markedly. Also the branched-chain and the basic amino acids reduced BV significantly. In the barley-based diets negative effects were also observed when the concentration of the single amino acid was doubled. However, it was assumed that the observed deleterious effects of amino acid excess were partly due to an exaggerated lysine deficiency in the barley protein when non-limiting amino acids were added.3. The results with various combinations of egg and potato proteins showed that as potato protein was increased true protein digestibility decreased linearly, whereas BV decreased Curvilinearly. Maximum protein utilization was obtained with egg protein alone.

scholarly journals Interactions among the branched-chain amino acids and their effects on methionine utilization in growing pigs: effects on nitrogen retention and amino acid utilization

2000 ◽  
Vol 83 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Stefan Langer ◽  
Malcolm F. Fuller
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Block Design ◽  
Nitrogen Retention ◽  
Growing Pigs ◽  
Deficient Diet ◽  
Randomized Block Design ◽  
Amino Acid Utilization ◽  
Limiting Amino Acid ◽  
Branched Chain

An experiment was conducted to investigate the effects of branched-chain amino acid (BCAA) interactions on their utilization by growing pigs and the effects of excessive amounts of BCAA (leucine, isoleucine, valine) on the utilization of methionine. A semipurified diet containing 100 g crude protein/kg with a balanced amino acid pattern was prepared using casein supplemented with free amino acids. Three further diets were made by reducing the concentration of methionine + cyst(e)ine, valine or isoleucine by 20 %. Each of these four diets was then supplemented with leucine (50 % excess) or a mixture of BCAA (50 % excess of each but excluding the limiting amino acid). All diets were isoenergetic and were made isonitrogenous by replacement of glutamic and aspartic acids. The twelve diets were given to twenty-four growing pigs (30–40 kg) in three periods according to a randomized block design. Each period lasted 8 d and N retention was measured during the last 5 d of each period. Reducing dietary methionine, valine or isoleucine reduced the utilization of N (N retained/N digested) by approximately 20 % (P < 0·05). Adding leucine to the isoleucine-limiting diet decreased the utilization of N by 9 % (P < 0·05). This was reversed by simultaneous addition of valine. Excess leucine in a valine-deficient diet did not significantly reduce N utilization. In methionine-limiting diets an excess of either leucine alone or of all three BCAA increased the utilization of N by 8 % (P < 0·05).

scholarly journals Effect of varying supply of amino acids on nitrogen retention and growth performance of boars of different sire lines

2013 ◽  
Vol 56 (1) ◽  
pp. 751-765
Author(s):  
C. Otten ◽  
A. Berk ◽  
L. Hagemann ◽  
S. Müller ◽  
M. Weber ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Growth Performance ◽  
Nitrogen Balance ◽  
Performance Test ◽  
Nitrogen Retention ◽  
Feeding Trials ◽  
Amino Acid Levels

Abstract. Three diets with varying amino acid levels were fed in two nitrogen balance studies and two fattening experiments in order to determine the nitrogen retention and growth performance of boars of different sire lines. A total of 12 boars, 6 crossbreed boars sired by Piétrain boars (Study 1) and 6 crossbreed boars sired by Duroc boars (Study 2) were used in the nitrogen balance studies. The feeding trials with 214 boars (109 crossbreeds of Piétrain sire line 1×hybrid sow [Pi 1] and 105 crossbreeds Piétrain sire line 2×hybrid sow [Pi 2]) in Experiment 1 and 212 boars (106 Piétrain sire line 3×hybrid sow [Pi 3] and 106 Duroc×hybrid sow [Du]) in Experiment 2 were carried out in three performance test centres in parallel to the nitrogen balance studies.

PSX-A-5 Late-Breaking: Branched chain amino acid and threonine requirements for puppy (>14 wk-9mo) Labrador Retrievers using the indicator amino acid oxidation (IAAO) technique

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 363-364
Author(s):  
Jessica L Varney ◽  
Heather Adams ◽  
Sarah Cox ◽  
Kevin Cline ◽  
Rhianna Bailey ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Control Diet ◽  
Branched Chain Amino Acids ◽  
Acid Oxidation ◽  
Gut Health ◽  
Isoleucine Leucine ◽  
Amino Acid Oxidation ◽  
Branched Chain ◽  
Labrador Retrievers

Abstract Branched chain amino acids are heavily involved in protein synthesis and turnover, emphasizing the need to establish requirement for growing animals. On the other hand, threonine is vital for supporting proteins necessary for gut health. Thus, it is very important to supply branched chain amino acids and threonine in appropriate amounts to growing animals. In this experiment, the indicator amino acid oxidation (IAAO) technique was utilized to determine valine, isoleucine, leucine, and threonine requirements in six puppy Labrador Retrievers (&gt;14wk-9mo). Puppies were subjected to diets ranging from deficient to excess, with each of the indispensable amino acids formulated at 1.6x NRC values. The control diet was fed for two days of adaptation, followed by one experimental day in which the test diet was fed. On the test day, a breath sample was collected using a using a respiration mask (Oxymax, Columbus Instruments). A priming dose of L-[1-^13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on body weight was supplied to each puppy, followed by [1-^13C]Phe doses every 30 minutes, for a four hour period. ^13CO[2] was collected after each dose and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results from IRMS were converted to atom percent excess (APE) and analyzed using a segmented line model (JMP^® Pro 16). Each of the Four Rivers mean and population requirements were as follows: 1.72 ± 0.11 g/1000 kcal ME for valine; 1.43 ± 0.24 g/1000 kcal ME for isoleucine; 2.25 ± 0.15 g/1000 kcal ME for leucine; 1.74 ± 0.16 g/1000 kcal ME for threonine (mean ± 2SD). The knowledge gained from this study is highly useful as the lean mass deposited as a puppy influences the animal throughout their lifetime.

Amind Acid Requirements of the Normal Infant

PEDIATRICS ◽  
1955 ◽  
Vol 16 (5) ◽  
pp. 672-672
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Protein ◽  
Essential Amino Acid ◽  
Nitrogen Retention ◽  
Normal Growth ◽  
Essential Amino Acids ◽  
Normal Infant ◽  
Minimum Requirement ◽  
Sole Purpose

If the sole purpose of protein in the diet is to furnish amino acids, the amount needed is that which provides the required quantities of essential amino acids. In these studies the requirement of an essential amino acid is determined by feeding a diet made up of purified amino acids and shown to support normal growth (as evidenced by weight nitrogen retention and plasma protein). The amino acid under study is omitted and then reintroduced in increments until normal growth is resumed; the least amount of the amino acid necessary is considered to be the minimum requirement. Using this technique the minimum requirement for infants between 1 and 6 months of age for threonine was 60 mg./kg./day and for phenylalanine, 90 mg./kg./day. An infant ingesting 200 ml./kg./day of woman's milk would receive approximately 104 mg. of threonine and 106 mg. of phenylalanine/kg./day.

The isoleucine requirement of the weanling pig

1962 ◽  
Vol 58 (3) ◽  
pp. 413-422 ◽  
Author(s):  
R. E. Evans
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nitrogen Balance ◽  
Essential Amino Acid ◽  
Nitrogen Retention ◽  
Amino Acid Requirements ◽  
Main Criticism ◽  
Current Standards

The current standards or estimates of the essential amino acid requirements of swine are based almost wholly on growth trials. These were carried out with groups of three or four pigs fed individually on semisynthetic diets. The trials generally lasted for only 30–35 days since several expensive amino acids were being fed. The main criticism is that the values given were not adequately substantiated by carrying out nitrogen-balance determinations. It is also possible that the nitrogen-retention values might have led to different conclusions from those arrived at on the basis of the growth trials only. The standards must remain tentative until tested with a larger number of animals and until many more nitrogenbalance determinations have been carried out.

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