J. Dairy Sci. 894747–4757 American Dairy Science Association, 2006. Comparison of Net Por.pdf

J. Dairy Sci. 89:4747–4757 © American Dairy Science Association, 2006. Comparison of Net Portal Absorption with Predicted Flow of Digestible Amino Acids: Scope for Improving Current Models? D. Pacheco,*1 C. G. Schwab,† R. Berthiaume,* G. Raggio,‡ and H. Lapierre*2 *Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, Sherbrooke, QC, Canada J1M 1Z3 †University of New Hampshire, Durham 03824-3542 ´ ´ ‡Department of Animal Science, Universite Laval, Quebec, QC, Canada G1K 7P4 ABSTRACT ity of the undegradable fraction of forages and of mi- crobial protein is suggested to improve the relation- This study was undertaken to determine the rela- ship between predicted digestible flows and NPA. tionship between measured net portal absorptions Overall, this study indirectly confirms, across EAA, (NPA) and flows of digestible essential amino acids smaller losses through gut metabolism for His, Met, (EAA) predicted with the National Research Council and Lys, intermediate losses for the branched-chain model (NRC, 2001) or the Cornell Net Carbohydrate AA with the higher losses for Thr. and Protein System model (CNCPS, version 5.0.34). Key words: amino acid, net portal absorption, duode- Net portal absorption data were obtained from 33 nal flow measurements of portal-arterial pl