-Forty-three batches of cereals (10 of wheat, 10 of triticale, 5 of barley, 5 of rye, 7 of maize and 6 of sorghum) were analysed and studied for their nitrogen (N) and amino acid (AA) ileal digestibility. Each batch was tested on four castrated male pigs, weighing between 30 and 90 kg, and fitted with an end-to-end ileo-rectal anastomosis. Ileal true digestibility (TD) of AA was calculated by correcting ileal apparent digestibility (AD) for basal endogenous AA losses, measured by means of a protein-free diet. Ileal real digestibility (RD) of AA was calculated by correcting AD for total endogenous AA losses, estimated by a multiple regression model. TD of N and most AA decreased (P < 0.001) from wheat, triticale and maize, to barley and sorghum and to rye (90.3, 88.7, 89.9, 85.4, 83.7 and 80.1%, respectively, for the sum of all AA). Estimates of endogenous N losses decreased (P < 0.001) from triticale, sorghum and wheat, to maize, barley and rye (on average 3.10, 2.93, 2.63, 2.43, 2.27 and 2.16 g N . kg -1 DM ingested, respectively). Barley excluded, there was a trend toward increasing endogenous AA losses with increasing dietary acid detergent fibre (ADF) concentration (r = 0.57, P < 0.001). Barley caused low endogenous N losses relative to its ADF concentration.

Seven batches of maize gluten feed (MGF) were studied for their protein and amino acid standardised ileal digestibility (SID). Each batch was tested on four castrated male pigs Large White (LW) or (LW x Landrace-L) x (LW x Pietrain-P) weighing between 42 and 61 kg, and fitted with an end-to-end ileo-rectal anastomosis. In all batches, lysine, threonine, cystine, tryptophan, aspartic acid and glycine displayed the lowest SID values (on average 62.9, 69.6,66.7, 64.1,69.7 and 62.4%, respectively). On the contrary, methionine, arginine, leucine, tyrosine and phenylalanine were among the most digestible amino acids and their average SID reached 84.8, 85.6, 82.3, 83.2 and 82.7%, respectively. Significant differences between batches of MGF appeared for SID of most amino acids. SID of most amino acids decreased as the proportion of N bound to the NDF residue increased.

-Ten batches of wheat milling by-products -3 of wheat middlings (WM), 4 of wheat feed (WF), 3 of wheat bran (WB) -were analysed and studied for their protein and amino acid ileal true digestibility (ITD). Each batch was tested on four castrated male pigs weighing between 35 and 95 kg, and fitted with an end-to-end ileo-rectal anastomosis. In all types of by-products, lysine and threonine were among the least digestible amino acids, whereas methionine was among the most digestible ones. N and all amino acids ITD decreased significantly (P < 0.05) from WM to WF and to WB. In WM, the average N, lysine, threonine and methionine ITD values were 93.6, 90.8, 90.4 and 95.1%, respectively. They decreased to 85.5, 86.6, 83.3 and 91.5%, respectively in WF and down to 70.1, 68.3, 68.4 and 78.9%, respectively in WB. N and all amino acids ITD was predicted according to either the ratio of the feedstuff fibre to amino acid concentrations, or the proportion of total N bound to the NDF (neutral detergent fibre) residue, or both. For most amino acids, the use of CF (crude fibre), ADF (acid detergent fibre) or ADL (acid detergent lignin) as fibre criteria provided accurate equations with coefficient of determination higher than 90%. wheat milling by-products / ileal digestibility / amino acids / pigsRésumé -Digestibilité iléale des acides aminés des issues de meunerie chez le porc. L'objectif de ce travail était de mesurer la digestibilité iléale des acides aminés des issues de meunerie chez le porc et d'en déterminer les principaux facteurs de variation. Dans ce but, dix lots commerciaux de coproduits de meunerie (3 lots de farine basse, 4 lots de remoulage et 3 lots de sons) ont fait l'objet d'une caractérisation analytique et d'une mesure de digestibilité iléale des acides aminés. Les caractéristiques suivantes ont été analysées : azote, acides aminés, amidon, matière minérale, matière grasse, cellulose brute (CB), NDF (neutral detergent fibre), ADF (acid detergent fibre), ADL (acid detergent lignin) et teneur en azote du résidu NDF (NNDF). Chacun des lots a été testé sur quatre porcs mâles Ann. Zootech. 49 (2000) 55-65 55

. Ileal amino acid digestibility and estimates of endogenous amino acid losses in pigs fed rapeseed meal, sunflower meal and soybean meal. Can. J. Anim. Sci. 80: 495-506. Four commercial samples of rapeseed meal (RSM), four of sunflower meal (SFM) and nine of soybean meal (SBM) were analysed and their ileal N and amino acid (AA) digestibilities in growing pigs were studied. Each batch was tested on four castrated male pigs weighing between 40 and 100 kg and fitted with an end-to-end ileo-rectal anastomosis. True ileal digestibility (TD) of AA was calculated by correcting apparent ileal digestibility (AD) for basal endogenous AA losses, measured by means of a protein-free diet. For RSM and SBM, total endogenous gut AA losses were estimated by a multiple regression model and real ileal digestibility (RD) of AA was calculated. In RSM, average TD of lysine, threonine and methionine were 70.7, 73.2 and 86.0%, respectively. These values were 80.0, 81.8 and 91.9%, respectively in SFM and 90.5, 86.8 and 93.0%, respectively, in SBM. In SBM, TD decreased (P < 0.05) with increases in the ratio of dietary acid detergent fibre (ADF) to AA contents. Expressed as g kg -1 dry matter (DM) intake, total endogenous gut N losses reached 4.7 to 6.4 for RSM and 1.9 to 3.5 for SBM. For SBM, they increased (P < 0.001) with dietary ADF concentration and RD of most AA decreased (P < 0.05) with the increase in the ratio of dietary neutral detergent fibre (NDF) to AA concentrations.

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