049 Physiological and molecular mechanisms associated with performance, immunometabolic status, and liver function in transition dairy cows fed rumen-protected methionine or choline

作者：Zhen Zhou, M. Vailati-Riboni, Omar Bulgari, Erminio Trevisi, Timothy A. Garrow, J.K. Drackley, Pedro Cardoso, D. Luchini, Juan J. Loor · 发表于：Journal of Animal Science · 年份：2016 · DOI：10.2527/msasas2016-049 · 被引用次数：3 · 研究领域：Ruminant Nutrition and Digestive Physiology

The mechanisms underlying benefits of rumen-protected methyl donor supplementation during the transition period are largely unknown. Objectives were to evaluate performance, immunometabolic status, liver function, and the underlying mechanisms in response to rumen-protected methionine (MET) or choline (CHO) supplementation. Eighty-one multiparous Holstein cows were used in a randomized complete block design with 2 × 2 factorial arrangement of MET (Smartamine M; Adisseo NA) and CHO (ReaShure; Balchem Inc.) level (with or without). Treatments were control (CON) with no MET or CHO, CON + MET (SMA), CON + CHO (REA), and CON + MET + CHO (MIX). From −50 to −21 d before expected calving, all cows received the same diet (1.24 Mcal/kg DM). From −21 d to calving, cows received the same basal close-up diet (1.54 Mcal/kg DM) and were randomly assigned to treatments (CON, SMA, REA, or MIX). From calving to 30 d in milk, cows were on the same postpartal diet (1.69 Mcal/kg DM) and continued to receive the same treatments through 30 d in milk. Methionine supplementation was adjusted daily at 0.08% of diet DM and CHO was supplemented at 60 g·cow−1·d−1. Blood (−10, 4, 8, 20, and 30 d) and liver (−10, 7, 21, and 30 d) samples were harvested for biomarker and molecular analyses. Methionine supplementation led to greater DMI during close up (P = 0.01) and the first 30 d postpartum (P = 0.02). Milk yield (P = 0.03) and milk protein percent (P < 0.01) also were greater in MET-supplemented cows comp...