scholarly journals Challenging in Rats the Use of 13C Spirulina as Reference Protein for the Dual Isotope Method to Determine Amino Acid Bioavailability (P08-061-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Romain Tessier ◽  
Nadezda Khodorova ◽  
Juliane Calvez ◽  
Daniel Tomé ◽  
Claire Gaudichon
Keyword(s):  
Amino Acid ◽  
Goat Milk ◽  
Protein Digestibility ◽  
Male Rats ◽  
National Agency ◽  
Dual Isotope ◽  
Isotope Method ◽  
Reference Protein ◽  
Bonferroni Test

Abstract Objectives In order to establish DIAAS in humans, the FAO recommended to develop a new method to measure indispensable amino acid (IAA) digestibility. This method uses two isotopic labeling, one for the protein to test and one for a reference protein. Spirulina was chosen as the 13C reference protein due to its commercial availability and affordability. However, the real digestibility of spirulina protein has not been measured in vivo. This work aims to assess the digestibility of spirulina and its repeatability in different meal tests in rats. Methods 23 Wistar male rats were fed a test meal containing 0.5 g of 15 N protein from either spirulina (n = 7), sunflower n = 8) or goat milk isolate (n = 8) and 10 mg of 13C labeled spirulina. Rats were euthanized 6 h after the meal and their digestive luminal contents (stomach, small intestine, ileum, caecum, colon) were collected. Protein digestibility was determined for the test and the reference proteins by measuring 15 N and 13C enrichments in the digesta by EA-IRMS. Caecal IAA digestibility of 13C spirulina was determined by measuring the quantity of AA in the caecum by UPLC and the 13C enrichment in AA by GC-C-IRMS. Group effects were tested using one way ANOVA and differences between groups using Bonferroni test. Results Six hours after ingestion, most of the dietary 15 N and 13C were found in the caecum and colon. But there at least twice more 15 N nitrogen in the caecum and colon in the spirulina group than in the two other groups. Therefore, spirulina protein digestibility (86.0 ± 0.7%) was lower (P < 0.001) than sunflower (95.1 ± 0.5%) and goat milk digestibility (97.2 ± 0.2%). 13C spirulina digestibility tended to be different (P = 0.06) when mixed to spirulina (90.6 ± 0.6%), sunflower (88.8 ± 0.5%) or goat milk (89.0 ± 0.5%) isolates. The caecal IAA digestibility of 13C spirulina was lower in the spirulina group than in sunflower and goat milk groups for every IAA tested, and the mean was 91.6 ± 0.2% for sunflower, 91.4 ± 0.4% for goat milk and 85.4 ± 0.6% for spirulina. Conclusions Spirulina protein is of lower digestibility than other animal or plant proteins. Protein and amino digestibility of a tracer dose of 13C spirulina appears to vary depending on the protein component of the meal. These results question the use of spirulina as a reference protein for the dual isotope method. Funding Sources French Research National Agency (ANR), SOFIPROTEOL. Supporting Tables, Images and/or Graphs

scholarly journals 15N and ²H Intrinsic Labeling Demonstrate That Real Digestibility in Rats of Proteins and Amino Acids from Sunflower Protein Isolate Is Almost as High as That of Goat Whey

2019 ◽  
Vol 150 (3) ◽  
pp. 450-457 ◽  
Author(s):  
Romain Tessier ◽  
Nadezda Khodorova ◽  
Juliane Calvez ◽  
Romain Kapel ◽  
Alain Quinsac ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Goat Milk ◽  
Protein Digestibility ◽  
Protein Isolate ◽  
Plant Protein Sources ◽  
Male Wistar Rats ◽  
Sunflower Protein ◽  
Meal Ingestion

ABSTRACT Background In the context of developing plant protein sources for humans, sunflower is a good candidate in its form as an oilseed coproduct. Objectives We aimed to compare the real digestibility in rats of a sunflower isolate to that of goat whey protein. We also studied the efficiency of 15N and 2H intrinsic labeling in this assessment. Methods Sunflower seeds and goat milk were labeled with 15N and 2H. Male Wistar rats (10 wk old) were fed a meal containing 12% of either sunflower isolate (n = 8) or whey (n = 8). Six hours after meal ingestion, protein and amino acid digestibility were assessed by measuring nitrogen, hydrogen, and amino acids in the digesta, as well as isotope enrichments in the bulk and individual amino acids. The differences between groups and isotopes were respectively tested with an unpaired and a paired t test. Results Protein isolate purity was 87% for whey and 94% for sunflower. 2H and 15N enrichments were, respectively, 0.12 atom % (AP) and 1.06 AP in sunflower isolate and 0.18 AP and 0.95 AP in whey. Fecal 15N protein digestibility was 97.2 ± 0.2% for whey and 95.1 ± 0.5% for sunflower isolate. The use of 2H resulted in a lower digestibility estimate than 15N for whey (96.9 ± 0.2%, P &lt; 0.05) and sunflower (94.2 ± 0.5%, P &lt; 0.01). For both isotopes, protein digestibility was about 2% higher for whey than for sunflower isolate. Mean 15N amino acid caecal digestibility was 97.5 ± 0.2% for whey and 96.3 ± 0.2% for sunflower isolate. The values obtained with 15N and 2H resulted in significant differences ranging from −0.1% to 3.5%. The DIAAS was &gt;1.0 for whey and 0.84 for sunflower (lysine). Conclusions The protein and amino acid digestibility of sunflower isolate was high but its DIAAS reflected a moderate lysine imbalance. Despite slight differences with 15N, deuterium produced comparable results, making it suitable for in vivo digestion studies.

In vitrodetermination of dietary protein and amino acid digestibility for humans

2012 ◽  
Vol 108 (S2) ◽  
pp. S282-S287 ◽  
Author(s):  
Christine A. Butts ◽  
John A. Monro ◽  
Paul J. Moughan
Keyword(s):  
Amino Acid ◽  
Dietary Protein ◽  
Protein Digestibility ◽  
Nutritional Factors ◽  
Ileal Digestibility ◽  
Plant Fibre ◽  
Component Models ◽  
Physical And Chemical

The development, refinement and validation ofin vitrodigestibility assays for dietary protein and amino acids for single stomached mammals are reviewed. The general principles ofin vitrodigestibility assays and their limitations are discussed.In vitroprotein digestibility assays must be accurate, rapid, cheap, simple, robust, adaptable and relevant to the processes of digestion, absorption, and metabolism. Simplein vitromethods have the potential to give useful measures ofin vivoamino acid and protein digestibility for humans.In vitromethods, including the complex multi-component models of digestion simulating the various physical and chemical processes, require independent validation within vivodata from the target species or an acceptable animal model using the most appropriatein vivomeasure of digestibility. For protein sources devoid of anti-nutritional factors or plant fibre, true ileal digestibility is the recommendedin vivobaseline, while for plant proteins the recommendedin vivoassay is real ileal digestibility. More published comparative studies are required to adequately validatein vitrodigestibility assays.

scholarly journals Meat protein quality of Dormitator latifrons (Pisces: Eleotridae): arguments for use by rural communities

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Mao Ernesto Rafael Basto-Rosales ◽  
Olimpia Carrillo-Farnés ◽  
Cynthia Eugenia Montoya-Martínez ◽  
Daniel Badillo-Zapata ◽  
Gustavo Gustavo Rodríguez-Montes de Oca ◽  
...  
Keyword(s):  
Amino Acid ◽  
Rural Communities ◽  
Essential Amino Acid ◽  
Protein Quality ◽  
Amino Acid Content ◽  
Protein Digestibility ◽  
Amino Acid Profile ◽  
Meat Protein ◽  
Reference Protein

The objective of this study was to evaluate the quality of meat protein of Dormitator latifrons for humans based on its Protein Digestibility Corrected Amino Acid Score (PDCAAS). Wild and cultured specimens were evaluated for amino acid content using HPLC equipment. The calculation of PDCAAS was performed as follows: milligrams of essential amino acid in 1 g of test protein per milligram of the same amino acid in 1 g of reference protein per true digestibility. To evaluate the protein of D. latifrons in relation to that of other fish, PDCAAS was calculated from the proteins of eight fish usually used in human nutrition. D. latifrons has a good essential amino acid profile, providing the same nutritional quality as those of other fish. Although the meat of wild D. latifrons contributes only 73% of human lysine requirements, it can be complemented with other lysine sources.

scholarly journals Protein quality evaluation twenty years after the introduction of the protein digestibility corrected amino acid score method

2012 ◽  
Vol 108 (S2) ◽  
pp. S183-S211 ◽  
Author(s):  
Joyce Boye ◽  
Ramani Wijesinha-Bettoni ◽  
Barbara Burlingame
Keyword(s):  
Amino Acid ◽  
Quality Evaluation ◽  
Protein Quality ◽  
Protein Digestibility ◽  
Food Groups ◽  
Preparation Methods ◽  
Reference Protein ◽  
Amino Acid Score ◽  
Limiting Amino Acid ◽  
New Research

In 1989 the Joint FAO/WHO Expert Consultation on Protein Quality Evaluation recommended the use of the Protein Digestibility Corrected Amino Acid Score (PDCAAS) method for evaluating protein quality. In calculating PDCAAS, the limiting amino acid score (i.e., ratio of first limiting amino acid in a gram of target food to that in a reference protein or requirement) is multiplied by protein digestibility. The PDCAAS method has now been in use for 20 years. Research emerging during this time has provided useful data on various aspects of protein quality evaluation that has made a review of the current methods used in assessing protein quality necessary. This paper provides an overview of the use of the PDCAAS method as compared to other methods and addresses some of the key challenges that remain in regards to protein quality evaluation. Furthermore, specific factors influencing protein quality including the effects of processing conditions and preparation methods are presented. Protein quality evaluation methods and recommended protein intakes currently used in different countries vis-à-vis the WHO/FAO/UNU standards are further provided. As foods are frequently consumed in complement with other foods, the significance of the PDCAAS of single protein sources may not be evident, thus, protein quality of some key food groups and challenges surrounding the calculation of the amino acid score for dietary protein mixtures are further discussed. As results from new research emerge, recommendations may need to be updated or revised to maintain relevance of methods used in calculating protein quality.

Effects of hypoxia on in vivo glycine-C14 incorporation into pancreatic cell proteins

1965 ◽  
Vol 208 (6) ◽  
pp. 1177-1182 ◽  
Author(s):  
M. Don Turner ◽  
Anne C. Turner
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Liquid Scintillation ◽  
Experimental Series ◽  
Male Rats ◽  
Supernatant Fraction ◽  
Zymogen Granule ◽  
Pancreatic Cell ◽  
Cell Fractions

The effects of graded hypoxia on glycine-C14 incorporation into subcellular components were measured in the intact mammal. Groups of three fasted male rats were injected intraperitoneally with 5 µc of glycine-2-C14 and sacrificed at 5 (or 10), 15, 20, 30, and 45 min by decapitation. In one experimental series the environmental pO2 was maintained at 35 mm Hg for 2 hr before injection and throughout the experiment. In three other experimental series, the pO2 in the sealed chamber was maintained at 58, 48, and 38 mm Hg for 45 min before injection and for the duration of the experiment. The whole pancreases were rapidly removed, cooled, homogenized, and pooled before separation of cell fractions by ultracentrifugation. The specific activities (counts/min per µg of amino acid or protein N) were obtained for plasma and supernatant fraction ("cell sap") amino acids and for the purified proteins of zymogen granule, mitochondrial, microsomal, and cell sap fractions from micro-Kjeldahl analyses and liquid-scintillation counting. No detectable changes were found in the turnover of plasma amino acids during graded hypoxia. Amino acid incorporation into the proteins of all cell fractions was depressed stepwise with increasing degrees of hypoxia.

scholarly journals Real ileal digestibility of sunflower protein and amino acids in humans

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Romain Tessier ◽  
Juliane Calvez ◽  
Nadezda Khodorova ◽  
Alain Quinsac ◽  
Romain Kapel ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Healthy Volunteers ◽  
Protein Isolate ◽  
Nitrogen Flow ◽  
Dual Isotope ◽  
Ileal Digestibility ◽  
Isotope Method ◽  
Indispensable Amino Acids ◽  
Sunflower Protein

AbstractIntroduction:Sunflower protein is not used in human nutrition despite a relatively good amino acid composition. However, the bioavailability of sunflower isolate has never been measured in Humans. The goal of this work was to determine ileal digestibility of protein and amino acids from a sunflower isolate in healthy volunteers and to challenge newly developed dual isotope method.Materials and methods:Eight healthy volunteers were equipped with a naso-ileal tube. They received during four hours twelve doses of biscuits containing, in total, 25 g of 15N sunflower protein isolate together with 400 mg of a mixture of free 13C amino acids incorporated in chocolates. Polyethylene glycol was perfused as non-absorbable marker and ileal contents were collected during 8 hours after ingestion of the first meal. Real ileal digestibility was measured by assessing nitrogen and carbon content as well as 15N and 13C enrichments by EA-IRMS. Amino acid digestibility was determined by measuring 15N and 13C enrichments by GC-C-IRMS and quantity of amino acids by UPLC. Blood was collected for 8 h to determine 15N and 13C enrichments by GC-C-IRMS.Results:The ileal nitrogen flow was 2.7 ± 0.5 mL/min (mean ± SD). In average, 53.1 ± 12.0 mmol of exogenous nitrogen was recovered during the eight hours of experiment, resulting in an ileal digestibility of sunflower isolate was 85.6 ± 2.6 % of nitrogen ingested. 13C amino acids were also recovered at the ileal level. The mixture of free 13C revealed an ileal digestibility of 94.9 ± 0.9 %. Ileal indispensable amino acids digestibility and DIAAS are in progress.Discussion:Ileal digestibility of sunflower isolate incorporated in toasted biscuits was lower than the value found or a raw isolate in a rat model (94.5%). The study revealed that 5 % of free amino acids were not absorbed in the ileum. Amino acid digestibility will complete the study to evaluate the DIAAS of sunflower isolate and to compare values obtained with the standard method and with the dual isotope method.

scholarly journals Comparison of Dual Isotope and Ileal Sampling Methods for the Determination of the Amino Acid Digestibility of Pea Protein and Casein in Adult Humans

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 873-873
Author(s):  
Florence Guillin ◽  
Claire Gaudichon ◽  
Laetitia Guerin-Deremaux ◽  
Catherine Lefranc-Millot ◽  
Gheorghe Airinei ◽  
...  
Keyword(s):  
Amino Acid ◽  
Sampling Method ◽  
Protein Quality ◽  
Plasma Samples ◽  
Tracer Method ◽  
Pea Protein ◽  
Dual Isotope ◽  
Reference Protein ◽  
Dual Tracer

Abstract Objectives The measurement of amino acid (AA) digestibility of protein through direct ileal sampling is highly invasive and inappropriate for vulnerable populations, such as children or elderly. The new dual tracer method relies on comparing meal and plasma isotopic ratios of 1/a test protein 2/a reference protein (or AA mix) of known digestibility, each one being labelled with a different isotope. The aim of this study was to compare this new indirect dual tracer method to standard ileal method, for the determination of AA digestibility of pea protein and milk casein. Methods Fifteen healthy adult volunteers completed the study and were equipped with a naso-ileal tube. They were given 9 portions of mashed potatoes containing either pea protein or casein isolates that were intrinsically labelled with 15N and 2H. A 13C algal free AA mix was added in the meals as the reference for dual tracer method. Plasma samples were collected regularly from before the first ingestion to 8-h later, while ileal digesta were collected continuously. For ileal sampling method, the AA digestibility (RIDAA) was determined using the recovery a non-absorbable marker (PEG-4000) perfused in the ileum, and the measurement of 15N enrichment of the digesta. For the dual tracer method, the amount of AA absorbed (AbAA) was calculated by the ratio of 2H/13C enrichments in plasma and in meals. The isotopic enrichments were evaluated in digesta, plasma samples and meals by GC-C-IRMS. The AA content was measured in digesta and meals by U-HPLC. Results Mean AbAA and RIDAA of pea protein were 102.2 ± 3.1% and 94.3 ± 1.5%, respectively. Mean AbAA and RIDAA of casein were 91.9 ± 2.0% and 97.1 ± 0.8%, respectively. The dual tracer method overestimated by 10% and 5% the AA digestibility of pea protein and casein, respectively, and the variability was high. The mean ileal AA digestibility of the 13C free AA mix was high (98.1 ± 1.1%), which validated our choice to use it as the reference ‘protein’ in the dual tracer method. Conclusions Several AA digestibilities obtained with dual tracer method were in the same range as the digestibilities from ileal sampling method. The variability was high and the effect of the protein source was inconsistent. After further research and validation, the dual tracer method could lead to notable advances in the determination of protein quality in humans. Funding Sources Roquette.

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