Protein Digestibility-Corrected Amino Acid Scores and Digestible Indispensable Amino Acid Scores Differentially Describe Protein Quality in Growing Male Rats
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- 1 February 2015
- journal article
- research article
- Published by Elsevier BV in Journal of Nutrition
- Vol. 145 (2), 372-379
- https://doi.org/10.3945/jn.114.195438
Abstract
Background: The FAO has recommended replacing the protein digestibility–corrected amino acid score (PDCAAS) with the digestible indispensable amino acid score (DIAAS). Objective: The objective of this study was to compare aspects underlying the calculation of the DIAAS and PDCAAS, including 1) fecal digestibility vs. ileal digestibility, 2) using a single nitrogen digestibility value for all amino acids, and 3) the effect of truncation. Truncated PDCAAS and untruncated DIAAS values calculated as formally defined were also compared and DIAAS data presented for 14 dietary protein sources. Methods: Semisynthetic wheat starch–based diets were formulated to contain the test protein (as consumed by humans) source (whey- and soy-protein isolates, milk-, whey-, rice- and pea- protein concentrates, cooked kidney beans, roasted peanuts, cooked peas, corn-based breakfast cereal, cooked rice, cooked rolled oats, and wheat bran) as the sole nitrogen source and with an indigestible marker (titanium dioxide). Growing male rats (∼250 g bodyweight) were given a basal casein-based diet from day 1 to day 7 and then allocated (n = 6) to the test diets for day 8 to day 14 before ileal digesta were collected after the rats were killed. Total feces were collected from day 11 to day 14. Results: True fecal nitrogen digestibility was different (P < 0.05; 10% difference on average) from true ileal nitrogen digestibility for 11 of the 14 protein sources. True ileal nitrogen digestibility was different (P < 0.05) from true ileal amino acid digestibility for almost half of the indispensable and conditionally indispensable amino acids (differences ranged from 0.9% to 400%). DIAAS values ranged from 0.01 for a corn-based cereal to 1.18 for milk protein concentrate. Conclusion: Untruncated PDCAAS values were generally higher than a DIAAS values, especially for the poorer quality proteins; therefore, the reported differences in the scores are of potential practical importance for populations in which dietary protein intake may be marginal.Keywords
Funding Information
- New Zealand Government
This publication has 18 references indexed in Scilit:
- Available lysine and digestible amino acid contents of proteinaceous foods of IndiaBritish Journal of Nutrition, 2012
- Amino acid availability: aspects of chemical analysis and bioassay methodologyNutrition Research Reviews, 2003
- Protein Digestibility and Quality in Products Containing Antinutritional Factors Are Adversely Affected by Old Age in RatsJournal of Nutrition, 2003
- Nitrogen and Amino Acid Requirements: The Massachusetts Institute of Technology Amino Acid Requirement PatternJournal of Nutrition, 2000
- The Protein Digestibility–Corrected Amino Acid ScoreJournal of Nutrition, 2000
- The Digestible Amino Acid Composition of Several Milk Proteins: Application of a New BioassayJournal of Dairy Science, 1998
- A New Method for Determining Digestible Reactive Lysine in FoodsJournal of Agricultural and Food Chemistry, 1996
- 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 manBritish Journal of Nutrition, 1994
- Human Amino Acid and Protein Requirements: Current Dilemmas and UncertaintiesNutrition Research Reviews, 1989
- Bacterial activity in the hind‐gut of pigsZeitschrift für Tierphysiologie Tierernährung und Futtermittelkunde, 1975