Dominique Graviou - Academia.edu (original) (raw)

Papers by Dominique Graviou

HAL (Le Centre pour la Communication Scientifique Directe), Dec 2, 2003

HAL (Le Centre pour la Communication Scientifique Directe), Dec 31, 2002

HAL (Le Centre pour la Communication Scientifique Directe), Mar 23, 1993

HAL (Le Centre pour la Communication Scientifique Directe), Oct 6, 2009

HAL (Le Centre pour la Communication Scientifique Directe), Jun 20, 2004

HAL (Le Centre pour la Communication Scientifique Directe), Dec 8, 2004

HAL (Le Centre pour la Communication Scientifique Directe), 2000

HAL (Le Centre pour la Communication Scientifique Directe), Jun 23, 2010

HAL (Le Centre pour la Communication Scientifique Directe), Jun 20, 2016

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Annales de zootechnie, 1994

Utilisation de l'électrophorèse pour étudier la dégradation dans le rumen des protéines du tourte... more Utilisation de l'électrophorèse pour étudier la dégradation dans le rumen des protéines du tourteau de colza. J Aufrère, J Aufrère, D Graviou(INRA, unité Valeur alimentaire, station de recherches sur la nutrition des

HAL (Le Centre pour la Communication Scientifique Directe), 2001

The extent to which rumen soluble nitrogen can contribute to the intestinal protein¯ow is unknown... more The extent to which rumen soluble nitrogen can contribute to the intestinal protein¯ow is unknown. Therefore, a study was carried out to assess simultaneously the kinetics of: (1) protein disappearance from rumen bags; (2) the amount of various N products in the rumen¯uid contents: total nitrogen (N), ammonia nitrogen (NH 3-N), non-ammonia nitrogen (NAN), true protein (protein-N); (3) the electrophoretical characteristics of the protein in feeds, bag residues and ruminal¯uids. Measurements were made on four sheep fed successively with hay alone (basal) or 60% hay and 40% of (white lupin seeds,`Are Ás' variety untreated or extruded) or 65% hay and 35% pea (`Baccara' variety, unextruded or extruded). These seeds differed in their effective nitrogen degradability (DegN) assessed by an in situ method which gave results of, respectively, 0.954, 0.682 for control and extruded lupin (clupin and extlupin) and 0.657, 0.697 for control and extruded pea (cpea and extpea). In the ruminal¯uid, the various nitrogen forms (N, NH 3-N, NAN, protein-N) evolved differently depending whether the diet contained lupin or pea. The N contents were higher in the ruminal¯uid of the diets containing clupin or extlupin than for those containing cpea or extpea while the NH 3-N contents were close. For extruded seeds, the contents for the various nitrogen fractions were lower than for the corresponding control seeds following a slower degradation in the rumen, which was con®rmed by the DegN parameters. For the clupin, part of the nitrogen was transiently solubilised as protein (42% N at 1 h and 33% N at 2 h) while for pea, whether extruded or not and for the extlupin, the solubilised N was mainly in the form of peptides, amino-acids and NH 3-N.

Annales de zootechnie, 1995

The energy of compound feeds for ruminants depends primarily on the digestibility of their organi... more The energy of compound feeds for ruminants depends primarily on the digestibility of their organic matter (dOM), which can be predicted from various analytical criteria (chemical, microbiological and enzymatic). However, other constituents have to be assayed to predict the energy value expressed in digestible energy (DE), metabolisable energy (ME) or net energy expressed in UFL or UFV. Recently, near infrared spectroscopy (NIRS) was used to determine chemical composition with high accuracy and predict the digestibility and energy value of forages. We compared this method with classical analytical methods for determining the chemical composition and energy value of compound feeds for ruminants.

HAL (Le Centre pour la Communication Scientifique Directe), Oct 2, 1989

HAL (Le Centre pour la Communication Scientifique Directe), Apr 24, 2012

The objective of this study was to evaluate the effect of an exogenous amylase preparation on dig... more The objective of this study was to evaluate the effect of an exogenous amylase preparation on digestion of low-and high-starch diets in dairy cattle. Rumen and total-tract nutrient digestibility were measured in a 4 × 4 Latin square design with 28-d periods using 4 firstlactation cows cannulated at the rumen and duodenum. Corn silage-based diets had 20 or 30% starch, attained by changing the composition of concentrate, with or without addition of an exogenous amylase preparation. Effects of the enzyme additive were observed on ruminal digestibility but not at the total-tract level. Ruminal digestibility of starch increased from 75% in control to 81% with amylase supplementation. This difference in ruminal starch digestion was compensated postruminally, so that the total-tract digestibility of starch was almost complete and did not differ between treatments. The amylase supplement also increased the true ruminal digestibility of organic matter but did not affect microbial N flow to the duodenum. Amylase supplement reduced the proportion of acetate and butyrate and increased that of propionate, particularly in the high-starch diet, where it tended to increase the concentration of total volatile fatty acids in the rumen. Other effects were a higher amylase activity in the solid-associated microbial community and a tendency for lower numbers of protozoa. In contrast, we observed no changes in intake, production, dry matter and fiber (neutral detergent fiber and acid detergent fiber) digestibility, or ruminal digestion, and no or small changes on selected fibrolytic and amylolytic bacteria and on the microbial community in general. We conclude that the exogenous amylase improved starch digestion in the rumen in first-lactation cows with moderate intake and production levels.