Ileal Digestibility of Nitrogen and Amino Acids in Human Milk and an Infant Formula as Determined in Neonatal Minipiglets

• Published in: The Journal of nutrition Vol. 153; no. 4; pp. 1063 - 1074
• Main Authors: Charton, Elise, Henry, Gwénaële, Cahu, Armelle, Le Gouar, Yann, Dahirel, Patrice, Moughan, Paul J., Montoya, Carlos A., Bellanger, Amandine, Dupont, Didier, Le Huërou-Luron, Isabelle, Deglaire, Amélie
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2023; American Institute of Nutrition
• Subjects: Alanine; Amino acids; Amino Acids - metabolism; Animal Feed - analysis; Animals; Bioavailability; Breast milk; Cobalt; Diet; Diet, Protein-Restricted; Digestibility; digestible indispensable AA score; Digestion - physiology; Ethylenediaminetetraacetic acids; Euthanasia; Female; Food and Nutrition; human milk; Humans; Ileum - metabolism; Infant; Infant Formula - chemistry; Infant formulas; infant nutrition; Infant, Newborn; Infants; Life Sciences; Lysine; Male; Milk; Milk, Human - chemistry; multiple hydrolysis; Neonates; Newborn babies; Nitrogen; Nitrogen - metabolism; Phenylalanine; Protein folding; Proteins; Statistical analysis; Swine; Threonine; true digestibility; Tryptophan; Tryptophan - metabolism; Valine; AA; multiple hydrolysis; digestible indispensable AA score; HM; human milk; HMO; NPN; DIAAS; TID; infant nutrition; bioavailability; PF; true digestibility; IF; tryptophan; Infant formula; digestible indispensable AA score tryptophan
• ISSN: 0022-3166; 1541-6100; 0022-3166
• DOI: 10.1016/j.tjnut.2023.02.025

Infant formula (IF) has to provide at least the same amount of amino acids (AAs) as human milk (HM). AA digestibility in HM and IF was not studied extensively, with no data available for tryptophan digestibility. The present study aimed to measure the true ileal digestibility (TID) of total nitrogen and AAs in HM and IF to estimate AA bioavailability using Yucatan mini-piglets as an infant model. Twenty-four 19-day-old piglets (males and females) received either HM or IF for 6 days or a protein-free diet for 3 days, with cobalt-EDTA as an indigestible marker. Diets were fed hourly over 6 h before euthanasia and digesta collection. Total N, AA, and marker contents in diets and digesta were measured to determine the TID. Unidimensional statistical analyses were conducted. Dietary N content was not different between HM and IF, while true protein was lower in HM (−4 g/L) due to a 7-fold higher non-protein N content in HM. The TID of total N was lower (P < 0.001) for HM (91.3 ± 1.24%) than for IF (98.0 ± 0.810%), while the TID of amino acid nitrogen (AAN) was not different (average of 97.4 ± 0.655%, P = 0.272). HM and IF had similar (P > 0.05) TID for most of the AAs including tryptophan (96.7 ± 0.950%, P = 0.079), except for some AAs (lysine, phenylalanine, threonine, valine, alanine, proline, and serine), with small significant difference (P < 0.05). The first limiting AA was the aromatic AAs, and the digestible indispensable AA score (DIAAS) was higher for HM (DIAASHM = 101) than for IF (DIAASIF = 83). HM, compared to IF, had a lower TID for total N only, whereas the TID of AAN and most AAs, including Trp, was high and similar. A larger proportion of non-protein N is transferred to the microbiota with HM, which is of physiological relevance, although this fraction is poorly considered for IF manufacturing.