References of "Leterme, Pascal"
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See detailAlimentation du porc: digestibilité des acides aminés.
Leterme, Pascal; Thewis, André ULg

in Agricontact (1998), (304), 1-6

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See detailThe Current N-15-Leucine Infusion Technique Is Not Suitable For Quantitative Measurements Of Ileal Endogenous Amino Acid Flows In Pigs
Leterme, Pascal; Seve, Bernard; Thewis, André ULg

in Journal of Nutrition (1998), 128(11), 1961-1968

The current 15N-leucine infusion technique may overestimate the ileal endogenous nitrogen losses in pigs. To determine the reason, we infused four cannulated pigs intravenously, fed them a pea-based diet ... [more ▼]

The current 15N-leucine infusion technique may overestimate the ileal endogenous nitrogen losses in pigs. To determine the reason, we infused four cannulated pigs intravenously, fed them a pea-based diet with 15N-leucine, and examined some methodological variables. Neither the blood sampling time nor the choice of precursor pool (total N or amino acid N of deproteinized plasma) or the method of estimation of the isotopic equilibrium level significantly affected the results. On the other hand, the 15N-enrichment of purified mucin, isolated from ileal digesta, was higher than that of the plasma amino acid pool (0.114 vs. 0.077 atom % excess). The endogenous proportion of the labeled amino acids (Ala, Gly, Ile, Leu and Val) in the ileal digesta ranged from 23 (Leu) to 74% (Ala), compared with 70% for total N. The low value of leucine was ascribed to the constant marker infusion condition. In pigs infused with 13C-leucine, a similar endogenous proportion was obtained for lumenal leucine with 13C-leucine and 15N-leucine infusion. However, the 13C-enrichment of the leucine bound to mucin was markedly lower than that of plasma leucine (38%). The endogenous amino acid flows were also estimated by combining the ileal N flow measured with 15N and the endogenous amino acid profile obtained by means of an N-free diet. They were different from those obtained with the 15N-amino acid dilution technique. We conclude that the precursor pool currently used (plasma total N or total a-amino acid N pools) is a poor indicator of the enrichment of the secretions and that the infusion of one labeled amino acid is not sufficient to extend the method at the amino acid level. [less ▲]

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See detailThe High Water-Holding Capacity Of Pea Inner Fibers Affects The Ileal Flow Of Endogenous Amino Acids In Pigs
Leterme, Pascal; Froidmont, Eric; Rossi, Florence et al

in Journal of Agricultural and Food Chemistry (1998), 46(5), 1927-1934

Pigs were fed protein-free diets containing different pea inner fiber (PIF) isolates (from wrinkled or smooth peas, unprocessed or micronized) or different PIF levels (from 50 to 200 g/kg diet), and the ... [more ▼]

Pigs were fed protein-free diets containing different pea inner fiber (PIF) isolates (from wrinkled or smooth peas, unprocessed or micronized) or different PIF levels (from 50 to 200 g/kg diet), and the flows of endogenous N and amino acids were measured at the ileum level. The flows were better correlated to the water-holding capacity (WHC) of the diet than to fiber intake (R2 = 0.996 vs 0.76, respectively). The relationship with WHC was of the exponential type, with a high increase when the WHC exceeded 3 g of water/g diet. A similar pattern and correlation (R2 = 0.98) was obtained for the ileal flow of nucleobases (markers of epithelial cells and bacteria), whereas the relationships with crude mucus (R2 = 0.96) and diaminopimelic acid (marker of bacteria, R2 = 0.55) were linear. N retention by pigs fed with 0, 30, 60, or 90 g/kg of dry matter (DM) of the same protein isolates did not differ significantly in pigs receiving a 40 or 160 g of PIF/kg diet, despite significant differences in ileal N and amino acid flows between the two fiber levels (2.0 and 3.1 g of N/kg of DM intake, on average). These results and those of the flow of endogenous N compounds suggest an effect of the swollen fibers on the intestinal wall rather than a disturbance of the digestive processes. [less ▲]

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See detailEffet des protéines et des fibres alimentaires sur les pertes iléales d'acides aminés endogènes chez le porc.
Leterme, Pascal; Rossi, Florence; Thewis, André ULg

in Journées de la Recherche Porcine en France (1997), 29

An N-free diet was supplemented with limited but increasing amounts of proteins (30, 60, 90 g/kg diet from a mixture of casein and egg yolk), in order to measure their effect on the ileal endogenous amino ... [more ▼]

An N-free diet was supplemented with limited but increasing amounts of proteins (30, 60, 90 g/kg diet from a mixture of casein and egg yolk), in order to measure their effect on the ileal endogenous amino acid (AA) losses in pigs. The study was conducted at 2 dietary fibre levels: 20 and 80 g/kg, isolated from pea seeds. Compared to the N-free diet, a supply of 30 g proteins was sufficient to obtain a positive N retention and the following supplies allowed a constant and linear increase (0.88 g N retained/g N intake). The same supply induced an increase in ileal endogenous losses, compared to the control (10.7 vs 7.2 g AA/kg DMi for the low fibre diet) but the difference was not significant because of a high variability between the pigs. The supplies of 60 and 90 g proteins did not modify the level of the losses either: 10.2 and 10.6 g AA/kg DMi, respectively. The same trends were observed for the diets with a high fibre level but, in this case, the losses were significantly higher: respectively 14.9, 16.7, 15.7 and 17 g AA/kg DMi. On the other hand, the fraction of the digesta containing the free AA and the small peptides (< 3 kDa), supposed to be mainly of dietary origin, remained independent of the protein level. This suggests a virtually complete digestibility of the dietary proteins. Thus, pea fibres induce a significant increase of the ileal endogenous losses but without disturbing the protein digestion process, as suggested by the N retention. The protein supply probably increased the digestive secretions but the latter could have been highly reabsorbed, due to a lack in dietary factors susceptible to increase the reabsorption. [less ▲]

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See detailValeur protéique des matières premières destinées à l'alimentation des porcs: nouvelles perspectives.
Leterme, Pascal; Thewis, André ULg

Article for general public (1997)

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See detailRéduction des rejets azotés chez le porc par l'alimentation.
Leterme, Pascal; Thewis, André ULg

in Efficience de l'azote en production végétale et animale, Journée d'Etude organisée par le Centre de Recherches Agronomiques et la Faculté Universitaire des Sciences Agronomiques (1997)

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See detailThe 13C- vs the 15N-leucine infusion technique for the determination of the ileal endogenous N losses in pigs.
Leterme, Pascal; Thewis, André ULg; Seve, Bernard

in Lindberg, J. E.; Ogle, Brian (Eds.) Digestive Physiology of Pigs (1997)

Some methodological aspects of the isotope dilution technique using 15N-leucine as a marker of the endogenous N secretions (choice of the precursor pool, time of blood collection, estimation of the ... [more ▼]

Some methodological aspects of the isotope dilution technique using 15N-leucine as a marker of the endogenous N secretions (choice of the precursor pool, time of blood collection, estimation of the isotopique equilibrium) were studied in pigs. Their effect on the estimation of the ileal endogenous N flow was limited. When 15N-leucine was replaced by 13C-leucine, the ileal endogenous N flow obtained with 13C was much lower than that obtained with 15N (1.4 vs 5.7g N/kg DM intake, respectively). The validity of the 13C-leucine infusion technique is questioned. [less ▲]

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See detailLes pertes iléales azotées endogénes chez le porc: effet de la composition, de la mouture et du taux d'incorporation des fibres internes de la graine de pois dans les aliments.
Leterme, Pascal; Froidmont, Eric; Thewis, André ULg

in Journées de la Recherche Porcine en France (1996, February), 28

The effect of the chemical composition, the grinding or the dietary level of the pea grain inner fibres on the ileal endogenous nitrogen losses in pigs was studied in three experiments. The intake of ... [more ▼]

The effect of the chemical composition, the grinding or the dietary level of the pea grain inner fibres on the ileal endogenous nitrogen losses in pigs was studied in three experiments. The intake of wrinkled pea inner fibres and starch slightly increased the ileal endogenous amino acid losses compared to smooth peas. The addition of micronized fibres (< 50 μm) in N-free diets significantly decreased the endogenous losses compared to untreated fibres. The water-holding capacity of the latter was higher than that of the micronized fibres (13 vs 4 g water/kg DM). The addition of increasing levels of fibres in diets (5, 10, 15, 20 % raw fibres, i.e. 2.5, 5.0, 7.5, 10 % AOAC fibres) proportionally increased the endogenous losses. The flow of total amino acids estimated for a diet free of fibres reached 6.47 g/kg DM intake and each gramme of AOAC fibre added per kg diet increased the total endogenous amino acid losses of 0.04 g. [less ▲]

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See detailChemical Composition Of Pea Fibre Isolates And Their Effect On The Endogenous Amino Acid Flow At The Ileum Of The Pig
Leterme, Pascal; Thewis, André ULg; Van leeuwen, Piet et al

in Journal of the Science of Food and Agriculture (1996), 72(1), 127-134

Pea starch, hulls and cotyledon inner fibres, isolated from pea seeds, were incorporated in N-free diets, on a NDF-content basis, in order to study their effect on the ileal endogenous amino acid (AA ... [more ▼]

Pea starch, hulls and cotyledon inner fibres, isolated from pea seeds, were incorporated in N-free diets, on a NDF-content basis, in order to study their effect on the ileal endogenous amino acid (AA) excretion in the growing pig. Maize starch and wood cellulose were selected as references. The inner fibrecontaining diet was also supplemented with enzymatically hydrolysed casein (EHC) in order to test the peptide alimentation method on a diet containing a fibre source with a high water-holding capacity (WHC = 10.9 g water g-' DM). The fibres were also analysed by different methods (crude fibre, NDF, ADF, enzymatic-gravimetric method, Englyst method). The fibre content of the inner fibre fraction varied widely from one method to another and ranged from 109 g crude fibre to 480 g AOAC fibre kg-' DM. Compared to the 'maize starch + wood cellulose' diet (11.0 g AA excreted kg-' DM intake), pea starch had no effect on ileal AA losses (9.6 g), whereas pea hulls slightly increased them (14.2 g). The AA excretion dramatically increased with the incorporation of inner fibres (28.0 g), because of their very high WHC. The addition of EHC increased the output (48.0 g) further, at a level that can hardly be explained only by an increase of the endogenous secretions. The results suggest that the NDF content of grain legume products is not indicative of their effect on the ileal endogenous AA losses in pigs and that the physiological effects of fibres along the gastrointestinal tract are due to both their chemical and physical properties. [less ▲]

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See detailEffect Of Oral And Parenteral N Nutrition Vs N-Free Nutrition On The Endogenous Amino Acid Flow At The Ileum Of The Pig
Leterme, Pascal; Monmart, Thierry; Thewis, André ULg et al

in Journal of the Science of Food and Agriculture (1996), 71(2), 265-271

Two methods were tested for suppressing the depressive effect of N-free diets on the digestive secretions in pigs: the blood perfusion of amino acids (AA) or the peptide alimentation method. In the latter ... [more ▼]

Two methods were tested for suppressing the depressive effect of N-free diets on the digestive secretions in pigs: the blood perfusion of amino acids (AA) or the peptide alimentation method. In the latter, enzymically hydrolysed casein (EHC), composed of oligopeptides and free AA, was used as the source of nitrogen. The unabsorbed dietary N molecules were discarded from the ileal digesta by ultrafiltration or gel filtration, assuming that the endogenous fraction did not contain significant amounts of small molecules. The AA supply by blood perfusion had no effect on the ileal endogenous AA losses (8.0 g AA kg-' DM intake) in growing pigs (k 50 kg), compared with the N-free diet alone (8.3 g), whereas the EHC supplementation significantly increased them (18.0 8). The increase was due to both endogenous and dietary N. The presence of unabsorbed dietary AA in the ileal digesta was confirmed by the AA profile of the soluble molecules with a very low molecular mass (< 3 kDa), which was close to that of EHC. Both ultrafiltration (cut-offs of 3 or 10 kDa) and gel filtration methods, utilised to discard the remaining dietary molecules, also eliminated a significant proportion of endogenous AA. [less ▲]

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See detailThe Use Of N-15-Labeled Dietary Proteins For Determining True Ileal Amino Acid Digestibilities Is Limited By Their Rapid Recycling In The Endogenous Secretions Of Pigs
Leterme, Pascal; Thewis, André ULg; Francois, Etienne et al

in Journal of Nutrition (1996), 126(9), 2188-2198

We assessed the use of 15N-labeled dietary proteins as a possible tool for the determination of the true ileal amino acid (AA) digestibility in pigs. The first experiment was designed to study the dietary ... [more ▼]

We assessed the use of 15N-labeled dietary proteins as a possible tool for the determination of the true ileal amino acid (AA) digestibility in pigs. The first experiment was designed to study the dietary N excretion pattern at the ileum subsequent to the ingestion of a single 15N-labeled meal. In a second experiment, we compared ileal endogenous AA outputs and true AA digestibility estimates obtained in pigs ingesting 15N-labeled dietary proteins in a single meal vs. intravenous infusion of 15N-leucine for 10 d during the ingestion of a pea-based diet and a protein-free starch diet. The proportion of endogenous N found in the ¡leal digesta differed when the label was delivered orally (50%) vs. intravenously (72%) and changed with time. As a consequence, the true ileal AA digestibilities measured with labeled diets were lower. A third experiment demonstrated that this was due to the rapid recycling of labeled dietary N in endogenous moieties, because 15N was found in blood within 10 min of consuming the labeled meal, within 50 min of consumption in pancreatic enzymes, 90 min in bile and 4 h in ¡leal mucins. We conclude that the use of 15N-labeled meals for determination of true ¡leal AA digestibilities is limited by the fast recycling of dietary N in endogenous secretions following a single 15N-labeled meal. The accuracy of results will depend on meaningful estimates of AA flow during a limited period and accurate estimates of 15N in AA. [less ▲]

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See detailLa digestibilite ileale reelle des acides amines chez le porc methodes d'estimation et interet pratique.
Leterme, Pascal; Thewis, André ULg

in 27èmes Journées de la recherche porcine en France (1995, February)

The estimation of the true ileal digestibility of dietary amino acids in pigs requires the distinction between the flow of undigestive dietary amino acids reaching the end of the small intestine and the ... [more ▼]

The estimation of the true ileal digestibility of dietary amino acids in pigs requires the distinction between the flow of undigestive dietary amino acids reaching the end of the small intestine and the flow of endogenous amino aicds coming from the digestive secretions that are not reabsorbed. This article reviews the direct and indirect method available: N-free diet (classic or improved), the regression method, the homoarginin method, the isotope dilution technique using labelled animals or labelled dietary proteins and the in vitro methods. The cases where the knowledge of the true digestibility seems to be interesting are then studied (feedstuffs poor in proteins, rich in antinutritional factors, etc). Thereafter, different subjects are brought up for the discussion: the practical use of true digestibility values, the necessity of takinf the endogenous losses into account and the validity of the true digestibility as a predictor of the availability of an amino acid for the pig [less ▲]

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See detailRate of recycling of dietary nitrogen in the digestive secretions of the pig.
Leterme, Pascal; Thewis, André ULg; Monmart, Thierry et al

in Protein metabolism and nutrition. Proceedings 7th International Symposium, Vale de Santarem, Portugal, 24-27 May 1995. (1995)

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See detailEffect of the carbohydrate fractions of pea seeds on the endogenous amino acid flow at the ileum of the pig.
Leterme, Pascal; Van Leeuwen, Piet; Thewis, André ULg et al

in Proceeding of the 6th International Symposium on Digestive Physiology in Pigs, n°80. (1994, October)

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See detailThe true ileal digestibility of pea amino acids measured with 15N labelled diets or animal in pigs.
Leterme, Pascal; Van Leeuwen, Piet; Thewis, André ULg et al

in The 45th Annual Meeting of the EAAP, Edinburgh, 5-8 September, paper n°5 (1994, September)

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See detailPorc et reduction des rejets azotes.
Leterme, Pascal; Thewis, André ULg

in Agricontact (1994), (259), 3-4

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See detailDetermination of the true ileal digestibility of amino acids in pigs by means of 15N-labelled diets or animals.
Leterme, Pascal; Van Leeuwen, Piet; Thewis, André ULg et al

in Proceeding of the 6th International Symposium on Digestive Physiology in Pigs, n°80. (1994)

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See detailEffect of oral and parenteral nutrition on the endogenous amino acid flow at the ileum of the pig.
Leterme, Pascal; Monmart, Thierry; Morandi, Pierre et al

in Proceeding of the 6th International Symposium on Digestive Physiology in Pigs, n°80. (1994)

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