Journal Articles
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Item Ileal Digestibility of Nitrogen and Amino Acids in Human Milk and an Infant Formula as Determined in Neonatal Minipiglets(Elsevier Inc. on behalf of American Society for Nutrition, 2023-04) Charton E; Henry G; Cahu A; Le Gouar Y; Dahirel P; Moughan PJ; Montoya CA; Bellanger A; Dupont D; Le Huërou-Luron I; Deglaire ABACKGROUND: 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. OBJECTIVES: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.Item Effects of Different Protein Sources on Amino Acid Absorption and Plasma Appearance of Tryptophan, Large Neutral Amino Acids, and Tryptophan Metabolites in Pigs(Elsevier Inc on behalf of American Society for Nutrition, 2024-07-15) Giezenaar C; Montoya CA; Kreutz K; Hodgkinson S; Roy NC; Mace LJ; Fraser K; Fernstrom JD; McNabb WC; Moughan PJBACKGROUND: Absorption of tryptophan (TRP) across the gut epithelium is potentially modulated by competing large neutral amino acids (LNAAs), which could affect the appearance of TRP and its metabolites in the bloodstream. OBJECTIVES: This study aimed to determine, in a growing pig model of an adult human, the absorption of TRP and other LNAAs from the gastrointestinal tract, and plasma appearance of TRP, LNAAs, and TRP metabolites, in response to dietary proteins varying in TRP content. METHODS: Pigs were adapted for 7 d to each of 4 diets that differed in their protein source and TRP content: 1) alpha-lactalbumin (AL; 9.95 mg TRP/g diet DM), 2) whey protein (6.59 mg TRP/g), 3) casein (3.73 mg TRP/g), or 4) zein (0.14 mg TRP/g). On day 8, pigs were euthanised after a 12-h fast (baseline), or 1, 2, 3, 4, or 6 h after they received a test meal consisting of 45 g protein, or a protein-free meal (n = 6 pigs at each time in each meal group). Tryptophan and LNAA absorption from the small intestine, and appearance of TRP, LNAAs, and TRP metabolites (melatonin, serotonin, kynurenine pathway metabolites), in the portal vein and systemic circulation, were determined. RESULTS: AL intake resulted in sustained elevated plasma TRP concentrations after an overnight fast. The amount of TRP absorbed was dose-dependently related to protein TRP content (P = 0.028), with fastest rates for pigs fed AL (371 mg/h). Portal and systemic plasma TRP, TRP/LNAA, and the TRP metabolites were highest (P ≤ 0.05) after AL intake, and remained above baseline levels for ∼4 h postprandially. Absorption rates of TRP correlated with postprandial plasma TRP and TRP metabolites (P ≤ 0.05). CONCLUSIONS: In adult humans, postprandial plasma TRP and TRP metabolite concentrations can likely be modulated by the TRP content of the meal.Item Clonostachys rosea Promotes Root Growth in Tomato by Secreting Auxin Produced through the Tryptamine Pathway(MDPI (Basel, Switzerland), 2022-11-04) Han Z; Ghanizadeh H; Zhang H; Li X; Li T; Wang Q; Liu J; Wang A; Feng M-GClonostachys rosea (Link) Schroers is a filamentous fungus that has been widely used for biological control, biological fermentation, biodegradation and bioenergy. In this research, we investigated the impact of this fungus on root growth in tomato and the underlying mechanisms. The results showed that C. rosea can promote root growth in tomato, and tryptophan enhances its growth-promoting impacts. The results also showed that tryptophan increases the abundance of metabolites in C. rosea, with auxin (IAA) and auxin-related metabolites representing a majority of the highly abundant metabolites in the presence of tryptophan. It was noted that C. rosea could metabolize tryptophan into tryptamine (TRA) and indole-3-acetaldehyde (IAAId), and these two compounds are used by C. rosea to produce IAA through the tryptamine (TAM) pathway, which is one of the major pathways in tryptophan-dependent IAA biosynthesis. The IAA produced is used by C. rosea to promote root growth in tomato. To the best of our knowledge, this is the first report on IAA biosynthesis by C. rosea through the TAM pathway. More research is needed to understand the molecular mechanisms underlying IAA biosynthesis in C. rosea, as well as to examine the ability of this fungus to boost plant development in the field.