Digestion and nutrient net fluxes across the rumen, and the mesenteric- and portal-drained viscera in sheep fed with fresh forage twice daily: net balance and dynamic aspects
| Autor: | Laurence Bernard, Claude Poncet, Béatrice Chauveau, Didier Rémond, Pierre Nozière |
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| Rok vydání: | 2003 |
| Předmět: |
Male
Rumen Nitrogen Medicine (miscellaneous) Ileum Biology chemistry.chemical_compound Mesenteric Veins Animal science Nutrient Ammonia Intestine Small medicine Animals Amino Acids Essential amino acid chemistry.chemical_classification Blood Specimen Collection Sheep Nutrition and Dietetics Portal Vein Fatty acid Fatty Acids Volatile Small intestine Diet medicine.anatomical_structure Intestinal Absorption Liver chemistry Biochemistry Urea Animal Nutritional Physiological Phenomena Digestion |
| Zdroj: | British Journal of Nutrition. 89:649-666 |
| ISSN: | 1475-2662 0007-1145 |
| DOI: | 10.1079/bjn2003832 |
| Popis: | Digestion and portal net flux of nutrients were studied in sheep fed twice daily with fresh orchard-grass. Digestive flows were measured in six fistulated sheep using the double-marker technique. Three sheep were fitted with catheters and blood-flow probes, allowing nutrient net flux measurements across the portal-drained viscera (PDV), the mesenteric-drained viscera (MDV) and the rumen. Total tract apparent digestion of N was similar to portal net appearance of N, calculated as the sum of free amino acids (FAA), peptide amino acids (PAA), NH3, and urea net fluxes. PAA accounted for 25 % of non-protein amino acid net release across the PDV. With the exception of glycine and glutamate, the small intestine was the main contributor to this PAA net release. The essential amino acid (EAA) apparent disappearance between the duodenum and the ileum was lower than the net appearance of EAA (FAA + PAA) across the MDV. The value of PDV:MDV flux of free EAA was, on average, 78 %. The rumen accounted for 30 % of the net uptake of EAA by the PDV tissues not drained by the mesenteric vein. Rumen net release of acetate, propionate, butyrate, 3-hydroxybutyrate, and lactate accounted for 70, 55, 46, 77 and 52 %, respectively, of their portal net releases. Conversely, the small intestine was a net consumer of arterial acetate and 3-hydroxybutyrate. Dynamic study of nutrient net fluxes across the PDV showed that throughout a feeding cycle, the liver faced a constant flux of amino acids (AA), whereas volatile fatty acid and NH3net fluxes varied in response to the meal. The present study specified, in forage-fed sheep, the partitioning of nutrient net fluxes across the PDV and the role of peptides in portal net release of AA. |
| Databáze: | OpenAIRE |
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