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.

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. Key words: Oilseed meal, ileal digestibility, amino acid, endogenous losses, pig

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 WE. 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 WE. 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%.

Ileal digestibility of protein and amino acids was measured in pigs fed 13 round, tannin-free peas samples and related to the following physical, chemical and biological characteristics of these samples: thousand-seed weight, proportion of hulls, starch, fibre, crude protein, ether extract and ash contents, trypsin inhibitor activity and trypsin inhibitor activity per unit of crude protein (TIAP). Each pea sample was included in a diet containing starch, sucrose, minerals and vitamins and fed to four barrows (50 to 100 kg) fitted with an end-to-end ileo-rectal anastomosis. Standardised ileal protein and amino acid digestibilities, except for alanine of peas decreased linearly with increasing TIAP (P < 0.01) and was not affected by fiber content. For example standardized ileal digestibilities values (%) decreased by −0.1975, −0.1617, −0.2171, −0.2630, −0.2029 and −0.3536 per unit of TIAP (expressed in unit of trypsin inhibited per milligram crude protein), respectively, for crude protein and lysine, threonine, methionine, cystine and tryptophan. Key words: Peas, trypsin inhibitor activity, standardised ileal digestibilities, protein, amino acids, pig

Protein and amino acid ileal digestibility was measured in 31 smooth and tannin free pea (Pisum sativum) batches of different varieties grown in different places and. Each batch of peas was tested on four castrated male pigs, between 30 to 90 kg live weight, fitted with an end to end ileorectal anastomosis.Most of spring pea varieties, with low trypsin inhibitor activity (TIA), had high standardized ileal protein and amino acids digestibility: > 78 % for protein, > 82 % for lysine, > 77 % for threonine, > 80 % for methionine, > 72 % for cystine and > 73 % for tryptophan. Three batches with low TIA and low fibre content had slightly lower protein and amino acids digestibility which was in related to particular growing conditions. Winter varieties with medium or high TIA activity had lower protein and amino acid standardized ileal digestibilities. Overall, digestibility decreases with increased TIA.

The ileal digestibilities of protein and amino acids in samples of barley, wheat, soyabean meal and sunflower meal were determined using either pigs modified with end to end ileo-rectal anastomosis (IRA) or pigs fitted with an ileal T-cannula (TC). The ileal digestibilities determined by the two methods were generally in good agreement in wheat and soyabean meal. There were some differences in barley, and, in sunflower meal, the TC values were consistently lower than the IRA values. It is concluded that the digestibility values of protein and amino acids can be affected by the method of determination and that the magnitude of this effect is dependent on the characteristics of the diet being tested.

Le but de ces travaux est de comparer chez le porcelet en post-sevrage et chez le porc charcutier 1/ les modeles de prediction de la valeur energetique des aliments a partir de leur composition analytique, 2/ l’utilisation digestive des matieres grasses, 3/ la valeur energetique de quelques matieres premieres (en situation de regime complexe). Dans ce but, 14 regimes complexes formules a partir de 9 matieres premieres (ble, orge, mais, manioc, pois, tourteau de soja, graines de colza, huile de soja, son de ble) ont ete distribues a des porcelets en post-sevrage (12 kg) et a des porcs charcutiers (58 kg). Pour des teneurs en NDF comprises entre 100 et 200 g/kg MS, la digestibilite de l’energie est independante du type d’animal considere, mais depend de facon lineaire de la teneur en NDF des aliments. Pour des teneurs en matieres grasses comprises entre 20 et 100 g/kg MS, la digestibilite apparente des matieres grasses est independante du type d’animal considere mais depend de facon curvilineaire de la teneur en matieres grasses des aliments. Quant a la teneur en matieres grasses digestibles des aliments, elle depend de facon linaire de la teneur en matieres grasses totales du regime. Les teneurs en energie digestible du ble, de l’orge, du mais, du pois et du tourteau de soja en situation de regime complexe sont les meme chez le porcelet en post sevrage que chez le porc charcutier et sont comparables a celles figurant dans les tables. Pour le porc charcutier, le mode de calcul de la valeur energetique des matieres premieres (resolution par regression lineaire multiple) ne permet pas de determiner de maniere significative la valeur energetique du manioc 70, de la graine de colza, de l’huile de soja et du son de ble, probablement en raison de taux d’incorporation trop faibles (inferieur a 15 %).

The digestion of 2 batches of wheat, 4 batches of barley and 1 batch of pea was studied through ileal and faecal digestibility measurements, ileal viscosity measurements and also, for wheat and pea, through ileal transit time measurements. Ileal digestibility coefficients of organic matter and energy are higher for wheat than for barley or pea whereas faecal digestibility coefficients are similar for wheat and pea, and higher than for barley. Ileal viscosity of digesta is much faster for pea than for cereals while digesta seem to transit through the ileum at a faster rate for pea than for wheat.

Protein and amino acid ileal digestibility was measured in 18 smooth and tannin free pea batches then studied in relation with their chemical characteristics (starch, fibre, ash and fat contents, trypsin inhibitor activity) and their variety. Each batch was tested on four castrated males, from 30 to 90 kg liveweight, fitted with an end to end ileo-rectal anastomosis. Protein and amino acid ileal digestibility is higher for peas with TIA lower than 5 units/g DM than for peas with TIA above 10 units/g DM. Among batches with TIA lower than 5 units, digestibility is not correlated to any analysed criteria.

Phytasic activity and phytic P content, which are important factors in determining the availability of P, were measured in 56 wheat samples. The different agronomic and genetic factors which could have an influence on these two variables were studied. specifically N and/or P fertilisation, date of harvest, preharvest sprouting and variety of French wheat. Phytasic activity ranged from 206 to 775 mU g(-1), with an average of 508 mU g(-1) and a standard deviation of 109 mU g(-1). Only the variety of wheat appeared as a significant factor explaining the endogenous phytasic activity (P = 0.006). The phytic P content varied between 0.92 and 2.80 g kg(-1) DM, with an average of 2.18 g kg(-1) and a standard deviation of 0.35 g kg(-1) DM. None of the factors studied significantly affected the phytic P content of the wheat. This content was correlated with the total P content (r = 0.56: P < 0.05). The activity of the endogenous phytase was independent of the quantity of its substrate, the phytic phosphorus of the kernels of wheat.

Peas and field beans have been increasingly grown in Europe during the last 15 years, to improve self-sufficiency in protein-rich feedstuffs. The protein profile of these crops is characterized by a high lysine content (7.3% crude protein in peas) and a relative deficiency in sulphur amino acids and tryptophan. Protein digestibility is slightly lower than in soyabean meal, especially for pigs (0.74 in peas vs. 0.80 in soyabean meal) and for young animals, and appears variable both between and within species. This lower digestibility can partly be explained by the presence in some species or cultivars of antinutritional factors (ANF; e.g. protease inhibitors, lectins or tannins) and/or fibrous material, leading to low accessibility of legume seed protein to digestive enzymes. More work is needed to separate the effects of these factors and their practical importance. Because of the high variability of ANF activity, it also appears necessary to develop reliable and quick assays which allow a check and selection of batches by plant breeders or feed manufacturers. Owing to the high variability within each species of these characteristics it seems possible to improve the nutritional value of legume seeds by selective breeding. In the short term, technological treatments can also lead to improved utilization, especially in poultry, but attention has to be paid to the cost of these treatments.