Título:	Portal drained visceral flux, hepatic metabolism, and mammary uptake of free and peptide-bound amino acids and milk amino acid output in dairy cows fed diets containing corn grain steam flaked at 360 orsteam rolled at 490 g/L.
Autoria:	TAGARI, H. WEBB JUNIOR, K. THEURER, B. HUBER, T. DEYUONG, D. CUNEO, P. SANTOS, J. E. P. SIMAS, J. SADIK, M. ALIO, A. LOZANO, O. DELGADO-ELORDUY, A. NUSSIO, L. NUSSIO, C. M. B. SANTOS, F.
Afiliação:	H. TAGARI, HEBREW UNIVERSITY OF JERUSALEM; K. WEBB JUNIOR, VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY; B. THEURER, UNIVERSITY OF ARIZONA; T. HUBER, UNIVERSITY OF ARIZONA; D. DEYOUNG, UNIVERSITY OF ARIZONA; P. CUNEO, UNIVERSITY OF ARIZONA; J. E. P. SANTOS, UNIVERSITY OF ARIZONA; J. SIMAS, UNIVERSITY OF ARIZONA; M. SADIK, UNIVERSITY OF ARIZONA; A. ALIO, UNIVERSITY OF ARIZONA; O. LOZANO, UNIVERSITY OF ARIZONA; A. DELGADO-ELORDUY, UNIVERSITY OF ARIZONA; L. NUSSIO, UNIVERSITY OF ARIZONA; CARLA MARIS BITTAR NUSSIO, CPPSE; F. SANTOS, UNIVERSITY OF ARIZONA.
Ano de publicação:	2004
Referência:	Journal of Dairy Science, v.87, n.2, p.413-430, 2004.
Conteúdo:	Objectives were to measure net fluxes of free (FAA) and peptide bound amino acids (AA) (PBAA) across portal-drained viscera (PDV), liver, splanchnic, and mammary tissues, and of milk AA output of lactating Holstein cows (n = 6, 109 +/- 9 d in milk) as influenced by flaking density of corn grain. Cows were fed alfalfa-based total mixed ration (TMR) containing 40% steam-flaked (SFC) or steam-rolled corn (SRC) grain. The TMR were offered at 12-h intervals in a crossover design. Six sets of blood samples were obtained from indwelling catheters in portal, hepatic, and mammary veins and mesenteric or costoabdominal arteries every 2 h from each cow and diet. Intake of dry matter (18.4 +/- 0.4 kg/d), N, and net energy for lactation were not altered by corn processing. Milk and milk crude protein yields (kg/12-h sampling) were 14.2 vs. 13.5 and 0.43 vs. 0.39 for cows fed SFC or SRC, respectively. The PDV flux of total essential FAA was greater (571.2 vs. 366.4 g/12 h, SEM 51.4) in cows fed SFC. The PDV flux of total essential PBAA was 69.3 +/- 10.8 and 51.5 +/- 13.2 g/12 h for cows fed SFC and SRC, respectively, and differed from zero, but fluxes of individual PBAA rarely differed between treatments. Liver flux of essential FAA was greater in cows fed SRC, but only the PBAA flux in cows fed SRC differed from zero. Splanchnic flux of FAA and PBAA followed the pattern of PDV flux, but variation was greater. Mammary uptake (g/12 h) of total essential FAA was greater in cows fed SFC than SRC (224.6 vs. 198.3, SEM 7.03). Mammary uptake of essential PBAA was 25.0 vs. 15.1, SEM 5.2, g/12 h for cows fed SFC or SRC, respectively, and differed from zero in half of the PBAA. Milk output of EAA was 187.8 vs 175.4, SEM 4.4 g/12 h in cows fed SFC and SRC, respectively, and output of most essential AA consistently tended to be greater in cows fed SFC. It is apparent that PBAA comprise a portion of total AA flux across PDV and are affected by grain processing. Further, this pool supplies an important component of AA taken up by the mammary gland. Quantifying the contribution of PBAA may improve diet formulation with respect to intestinal absorption and mammary uptake of AA.
Thesagro:	Dieta
Palavras-chave:	Gado de leite Amino acid Peptide Dairy cow Flaked corn
Digital Object Identifier:	10.3168/jds.S0022-0302(04)73181-1
Tipo do material:	Artigo de periódico
Acesso:	openAccess
Aparece nas coleções:	Artigo em periódico indexado (CPPSE)