scholarly journals Comparison of the ileal and faecal digestibility of dietary amino acids in adult humans and evaluation of the pig as a model animal for digestion studies in man

1994 ◽  
Vol 71 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Angela M. Rowan ◽  
P. J. Moughan ◽  
M. N. Wilson ◽  
K. Maher ◽  
C. Tasman-Jones
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Terminal Ileum ◽  
Human Subjects ◽  
Growing Pigs ◽  
Microbial Colonization ◽  
Diaminopimelic Acid ◽  
Adult Human ◽  
Model Animal ◽  
Adult Humans

The aim of the study was to determine if there is a difference between ileal and faecal assays for determining amino acid and N digestibilities in adult human subjects. Comparison of true ileal amino acid and N digestibilities was also made between adult human subjects and growing pigs to establish the usefulness of the pig as a model animal. Five subjects with established ileostomies and six subjects with intact large bowels consumed a constant diet consisting of meat, vegetables, fruit, bread and dairy products for 7 d with collection of ileostomy contents or faeces respectively over the last 4 d. The study was repeated using 25 kg body weight ileostomized and intact pigs. Apparent amino acid and N digestibility coefficients were determined. For human subjects the faecal digestibility values were significantly higher (P < 0·05) than the ileal values for Arg, Asp, Gly, Phe, Pro, Ser, Thr and Trp. The faecal digestibility of Met was significantly lower than the ileal value. Determination of DNA, diaminopimelic acid (DAPA) and the digestibilities of pectin, hemicellulose and cellulose in human subjects indicated that some microbial colonization had occurred at the terminal ileum after formation of an ileostomy; however, this was not as extensive as in the large intestine. True ileal amino acid and N digestibilities were calculated after correcting for the endogenous contribution of amino acids at the terminal ileum determined using a protein-free diet. There were no significant differences between adult human subjects and pigs for true ileal dietary amino acid digestibility except for Thr, Phe, Cys and Met. There were no significant differences between adult humans and pigs for the ileal digestibility of dry matter and the faecal digestibility of gross energy.

scholarly journals Available versus digestible amino acids – new stable isotope methods

2012 ◽  
Vol 108 (S2) ◽  
pp. S306-S314 ◽  
Author(s):  
Rajavel Elango ◽  
Crystal Levesque ◽  
Ronald O. Ball ◽  
Paul B. Pencharz
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Stable Isotope ◽  
Growing Pigs ◽  
The Body ◽  
Whole Body ◽  
Food Protein ◽  
Adult Humans

The nutritive value of food protein sources is dependent on the amino acid composition and the bioavailability of the nutritionally indispensable amino acids. Traditionally the methods developed to determine amino acid bioavailability have focused on intestinal absorption or digestibility, which is calculated as the percent of amino acid intake that does not appear in digesta or faeces. Traditional digestibility based methods do not always account for gut endogenous amino acid losses or absorbed amino acids which are unavailable due to the effect of heat processing and the presence of anti-nutritional factors, though methods have been developed to address these issues. Furthermore, digestibility based methods require the use of animal models, thus there is a need to developin vivomethods that can be applied directly in human subjects to identify the proportion of dietary amino acids which is bioavailable, or metabolically available to the body for protein synthesis following digestion and absorption. The indicator amino acid oxidation (IAAO) method developed in our laboratory for humans has been systematically applied to determine almost all indispensable amino acid requirements in adult humans. Oxidation of the indicator amino acid is inversely proportional to whole body protein synthesis and responds rapidly to changes in the bioavailability of amino acids for metabolic processes. Using the IAAO concept, we developed a newin vivomethod in growing pigs, pregnant sows and adult humans to identify the metabolic availability of amino acids in foods. The stable isotope based metabolic availability method is suitable for rapid and routine analysis in humans, and can be used to integrate amino acid requirement data with dietary amino acid availability of foods.

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.

scholarly journals Amino acid availability: aspects of chemical analysis and bioassay methodology

2003 ◽  
Vol 16 (2) ◽  
pp. 127-141 ◽  
Author(s):  
Paul J. Moughan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chemical Analysis ◽  
Structural Damage ◽  
Human Subjects ◽  
Scientific Evidence ◽  
Hydrolysis Time ◽  
Amino Acid Availability

AbstractIt is important to be able to characterise foods and feedstuffs according to their available amino acid contents. This involves being able to determine amino acids chemically and the conduct of bioassays to determine amino acid digestibility and availability. The chemical analysis of amino acids is not straightforward and meticulousness is required to achieve consistent results. In particular and for accuracy, the effect of hydrolysis time needs to be accounted for. Some amino acids (for example, lysine) can undergo chemical modification during the processing and storage of foods, which interferes with amino acid analysis. Furthermore, the modified amino acids may also interfere with the determination of digestibility. A new approach to the determination of available lysine using a modifiedin vivodigestibility assay is discussed. Research is required into other amino acids susceptible to structural damage. There is recent compelling scientific evidence that bacterial activity in the small intestine of animals and man leads to the synthesis and uptake of dietary essential amino acids. This has implications for the accuracy of the ileal-based amino acid digestibility assay and further research is required to determine the extent of this synthesis, the source of nitrogenous material used for the synthesis and the degree of synthesis net of amino acid catabolism. Although there may be potential shortcomings in digestibility assays based on the determination of amino acids remaining undigested at the terminal ileum, there is abundant evidence in simple-stomached animals and growing evidence in human subjects that faecal-based amino acid digestibility coefficients are misleading. Hindgut microbial metabolism significantly alters the undigested dietary amino acid profile. The ileal amino acid digestibility bioassay is expected to be more accurate than its faecal-based counterpart, but correction of the ileal amino acid flow for amino acids of endogenous origin is necessary. Approaches to correcting for the endogenous component are discussed.

scholarly journals Excessive heating of 00-rapeseed meal reduces not only amino acid digestibility but also metabolizable energy when fed to growing pigs

2020 ◽  
Vol 98 (7) ◽  
Author(s):  
Maryane S F Oliveira ◽  
Markus K Wiltafsky-Martin ◽  
Hans H Stein
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Basal Diet ◽  
Rapeseed Meal ◽  
Sole Source ◽  
Heating Time ◽  
Growing Pigs ◽  
Metabolizable Energy ◽  
Negative Effects ◽  
Ileal Digestibility

Abstract Two experiments were conducted to test the hypothesis that both the degree of heating and the time that heat is applied will affect the concentration of DE and ME, and the apparent ileal digestibility (AID) and the standardized ileal digestibility (SID) of amino acids (AA) in 00-rapeseed meal (00-RSM) fed to growing pigs. The nine treatments were prepared using a conventional 00-RSM that was either not autoclaved or autoclaved at 110 °C for 15 or 30 min or at 150 °C for 3, 6, 9, 12, 15, or 18 min. In experiment 1, 20 growing barrows with an average initial BW of 21.2 ± 1.2 kg were randomly allotted to the 10 diets in a replicated 10 × 4 Youden square with 10 diets and four periods in each square. A corn-based basal diet and nine diets containing corn and each source of 00-RSM were formulated. Urine and fecal samples were collected for 5 d after 7 d of adaptation. In experiment 2, nine diets contained one of the nine sources of 00-RSM as the sole source of AA, and an N-free diet that was used to measure basal endogenous losses of AA and CP was formulated. Twenty growing barrows with an initial BW of 69.8 ± 5.7 kg had a T-cannula installed in the distal ileum and were allotted to a 10 × 7 Youden square design with 10 diets and 7 periods. Ileal digesta were collected on days 6 and 7 of each 7-d period. Results from the experiments indicated that there were no effects of autoclaving at 110 °C on DE and ME or on AID and SID of AA in 00-RSM, but DE and ME, and AID and SID of AA were less (P &lt; 0.01) if 00-RSM was autoclaved at 150 °C compared with 110 °C. At 150 °C, there were decreases (quadratic, P &lt; 0.05) in DE and ME, and in AID and SID of AA as heating time increased. In conclusion, autoclaving at 110 °C did not affect ME or SID of AA in 00-RSM, but autoclaving at 150 °C had negative effects on ME and SID of AA and the negative effects increased as heating time increased.

The effect of the plane of nutrition on the optimum dietary amino acid pattern for growing pigs

1990 ◽  
Vol 50 (1) ◽  
pp. 155-164 ◽  
Author(s):  
T. C. Wang ◽  
M. F. Fuller
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Basal Diet ◽  
Positive Control ◽  
Growing Pigs ◽  
Optimum Ratio ◽  
Dietary Amino Acid ◽  
Bean Meal ◽  
Soya Bean Meal ◽  
Digestible Amino Acids

ABSTRACTSix diets based on maize and soya-bean meal were prepared. The basal diet had a crude protein (CP) concentration of 171 g/kg. The same ingredients, together with maize starch, were used to give a diet with CP 131 g/kg. This diet was supplemented with all (positive control) or with three of the four amino acids lysine, threonine, tryptophan and methionine. Each diet was given at two rates of intake. From the results, the optimum ratio between these four amino acids at different planes of intake was calculated. Amino acid digestibility in the basal diet was measured at three intakes, using pigs fitted with T cannulas at the terminal ileum.The results showed that the optimum ratios between the four amino acids (expressed in terms of digestible amino acids) were not affected by the rate of food intake. The optimum ratio between the four amino acids (i.e. when they are equally limiting) was lysine 1·00, methionine + cystine 0-61, threonine 0·64 and tryptophan 0·20. Digestibility was not affected by the level of intake.

A Study of Relations between the Absorption of Amino Acids, Dipeptides, Water and Electrolytes in the Normal Human Jejunum

1975 ◽  
Vol 49 (5) ◽  
pp. 401-408 ◽  
Author(s):  
D. B. A. Silk ◽  
P. D. Fairclough ◽  
Nicola J. Park ◽  
Annette E. Lane ◽  
Joan P. W. Webb ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Sodium Chloride ◽  
Human Subjects ◽  
Sodium Content ◽  
Sodium Chloride Solutions ◽  
Electrolyte Absorption ◽  
Wide Range ◽  
Osmotic Solution ◽  
Normal Human

1. A double-lumen perfusion technique was used to study the effect of a wide range of concentrations of the dipeptide glycyl-l-alanine and its constituent amino acids on water and electrolyte absorption from iso-osmotic solutions in the upper jejunum of normal human subjects. 2. There was no significant absorption of water and electrolytes from sodium chloride solution (150 mmol/l) but the presence of the dipeptide or its constituent amino acids stimulated water and electrolyte absorption. 3. Water absorption reached a peak at increasing amino acid and dipeptide concentrations and then tailed off. Our data suggest that the tailing off is not solely due to the diminished sodium content of the solutions. 4. During perfusion of the dipeptide-sodium chloride and amino acid-sodium chloride solutions solute and water were absorbed as an iso-osmotic solution. Analysis of the results indicates that this could occur at high dipeptide concentrations only if the majority of the dipeptide enters the cell intact.

scholarly journals The optimum dietary amino acid pattern for growing pigs

1989 ◽  
Vol 62 (1) ◽  
pp. 77-89 ◽  
Author(s):  
T. C. Wang ◽  
M. F. Fuller
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Agricultural Research ◽  
Essential Amino Acids ◽  
Growing Pigs ◽  
Amino Acid Pattern ◽  
Single Amino Acid ◽  
N Retention ◽  
Dietary Amino Acid ◽  
Optimum Balance

A series of four nitrogen-balance experiments was carried out with growing pigs to determine the optimum balance amongst the amino acids in the diet. The reduction in N retention when 20 % of a single amino acid was removed from the diet was used to calculate a dietary amino acid pattern in which each amino acid would he equally limiting. A mixture of amino acids simulating the amino acid pattern of casein was used with the same efficiency as casein. From two successive deletion experiments an optimum balance amongst the essential amino acids was derived. Expressed relative to lysine = 100 this had threonine 72, valine 75, methionine + cystine 63, isoleucine 60, leucine 110, phenylalanine + tryosine 120, tryptophan 18. No estimate was made for histidine. Essential amino acids in this pattern were mixed with non-essential amino acids in ratios of 36:64 up to 57:43. The highest efficiency of N retention was achieved with diets having a ratio of at least 45:55. This included (g/16 g N) lysine 6 5, threonine 4.7, valine 4 9, methionine + cystine 4.1, isoleucine 3 9, leucine 7.2, phenylalanine + tyrosine 7.8, tryptophan 12. The N of diets with this amino acid pattern was utilized significantly better than when the pattern proposed by the Agricultural Research Council (1981) was used. The flow of amino acids past the terminal ileum of pigs given the semi-synthetic diet with this amino acid pattern was no greater than that observed with protein-free diets. The proposed pattern thus describes the intrinsic requirements of the growing pig for absorbed amino acids.

scholarly journals Studies on the nitrogen compounds of the faeces of dairy cows fed urea as the sole or partial source of nitrogen

1979 ◽  
Vol 51 (1) ◽  
pp. 506-513
Author(s):  
Terttu Ettala ◽  
Matti Kreula
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Dairy Cows ◽  
Acid Hydrolysis ◽  
Free Amino Acid ◽  
Total Nitrogen ◽  
Free Amino ◽  
Diaminopimelic Acid ◽  
Nitrogen Compounds ◽  
Soluble Nitrogen

The nitrogen compounds of the faeces of dairy cows on purified, protein-free feed with urea and small amounts of ammonium salts as the sole source of nitrogen (0-feed). on low-protein feed in which part of the protein was replaced with urea (ULP-feed) and on normal protein-containing feed (NorP-feed) were studied. The total nitrogen contents of the dry matter of the faeces were 2.5 ± 0.7 % on 0-feed, 2.4 ± 0.4 % on ULP-feed and 2.3 ± 0.6 % on NorP-feed. The proportion of urea- and ammonium nitrogen of the total nitrogen was 3.2 ± 2.4, 4.5 ± 2.4 and 3.7 ± 1.8 % respectively, and the proportion of nitrogen soluble in 70 % ethanol 10.9 ± 5.7, 9.9 ± 2.4 and 10.4 ± 3.8 % of the total nitrogen; the proportion of nitrogen in the free amino acid fraction was 4.1 ±2.9 on 0-feed, 1.6 ± 1.4 (P < 0.05) on ULP-feed and 3.2 ± 2.9 % on NorP-feed. The nitrogen insoluble in 70 % ethanol as a proportion of the total nitrogen was 82.3 ± 7.2 on 0-feed, 85.4 ± 5.0 on ULP-feed and 82.3 ± 7.2 % on NorP-feed. Of the total nitrogen of this insoluble fraction, the following proportions were released as amino acids by acid hydrolysis: 62.15 ± 8.5 % on 0-feed, 61.6 ± 10.7 % on ULP-feed and 59.0 ± 13.9% on NorP-feed. (α, Ɛ-diaminopimelic acid was 1.7 ± 0.6, 0.7 ± 0.2 (P < 0.05) and 1.2 ± 0,4 mol % respectively of the total amino acids of the hydrolyzate. The soluble nitrogen fraction was separated into free amino acid and »peptide» fractions, and the amino acid composition of both was determined, the latter after acid hydrolysis

scholarly journals Effects of Dietary Crude Protein Levels on Fecal Crude Protein, Amino Acids Flow Amount, Fecal and Ileal Microbial Amino Acids Composition and Amino Acid Digestibility in Growing Pigs

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2092
Author(s):  
Zhenguo Yang ◽  
Tianle He ◽  
Gifty Ziema Bumbie ◽  
Hong Hu ◽  
Qingju Chen ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Essential Amino Acid ◽  
Crude Protein ◽  
Growing Pigs ◽  
Protein Levels ◽  
Low Protein ◽  
Dietary Crude Protein ◽  
Amino Acids Composition ◽  
Protein Amino Acids

The purpose of this experiment was to evaluate the effects of low protein corn-soybean meal-based diets on fecal CP, amino acid (AA) flow amount, AA digestibility and fecal and ileal microbial AA composition in growing pigs. Eighteen pigs (initial body weight = 30 ± 1.35) were randomly divided into three groups and fed with basal diets with CP levels of 12%, 15% and 18%, respectively. The Lys, Met + Cys, Thr and Trp level in the 12% CP and 15% CP groups is the same as 18% CP group by the addition of four crystalline Lys, Met + Cys, Thr and Trp to the diet. The results showed that with the decrease of dietary CP level from 18% to 12%, the fecal total nitrogen (N), CP and total AA (TAA) flow amount decreased linearly (p < 0.05). Dry matter (DM) digestibility, CP digestibility, TAA digestibility, essential amino acid (EAA) digestibility and non-essential amino acid (NEAA) digestibility increased linearly with the decrease of dietary CP concentration from 18% to 12%. Compared with 18% CP group, the flow amount of Asp, Ser, Glu, Gly, Tyr, Val, Leu and Phe in feces of pigs in the 15% CP group and 12% CP group decreased significantly, while the flow amount of Arg in the 15% CP group was lower than that in the 18% CP group and 12% CP group. The fecal microbial N and AA of the 15% CP group were higher than those of the 18% CP and 12% CP groups. Fecal TAA flow amount decreased linearly with the decrease of the dietary CP levels from 18% to 12%. Fecal TAA and NEAA flow amount also decreased linearly with the decrease of dietary CP level from 18% to 12%. Except for Glu, Gly, Met, Tyr, Thr and Phe, there were significant differences among the three groups in the composition of 17 kinds of AAs in fecal microorganisms. Among the 17 AA compositions of ileal microorganisms, except Tyr and Lys, the other AAs were significantly different among the three groups (p < 0.05)

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