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Response to LPS challenge after intravenous amino acid infusion in postpartum dairy cows.

T. L. Chandler

Events

06-24-2020

Abstract:

399
Response to LPS challenge after intravenous amino acid infusion in postpartum dairy cows.
T. L. Chandler*, T. A. Westhoff, C. R. Seely, J. E. Cha, M. E. Van Amburgh, T. R. Overton, S. Mann. Cornell University Ithaca, NY.

Postpartum cows experience a heightened inflammatory state coinciding with energy and amino acid (AA) deficit. Our objective was to describe the response to a systemic inflammatory stimulus after a 4-d intravenous (IV) AA infusion designed to fill the cows' estimated MP deficit. Cows (n = 14, 4 � 1 DIM) were IV infused 24 h/d for 4 d in a matched-pair randomized controlled design and received IV AA (IVAA) or 0.9% NaCl (CTRL). Daily IVAA were infused at 10 mL/kg BW to supply 1 g/kg BW of essential AA (EAA) and nonessential AA (NEAA). After infusion ended, cows were IV infused with LPS (0.0625 �g/kg BW over 1 h) and blood samples were collected at 0, 1, 2, 3, 4, 8, and 24 h for analysis of glucose, nonesterified fatty acids (NEFA), insulin, glucagon, and AA. Repeated measures ANOVA in PROC MIXED (SAS v. 9.4) included fixed effects of time, treatment (trt), time � trt, DIM, parity, and BW, and random effect of pair. Glucose was similar (P > 0.15) between groups at 0 h (61 vs. 67 � 4 mg/dL, IVAA vs. CTRL � SEM) and decreased over time (P = 0.01) reaching a nadir at 2 h, but was lower (P < 0.01) in IVAA over the 24 h (55 vs. 64 � 3 mg/dL). Plasma NEFA were greater (P < 0.01) in IVAA following LPS [673 (473—957) vs. 426 (313—579) �eq/L, IVAA (95% CI) vs. CTRL (95% CI)], but changed over time (P = 0.02) in both groups (time � trt P = 0.21). Glucagon was greater (P < 0.01) in IVAA following LPS [242 (200—294) vs. 171 (142—204) pg/mL] and was similarly affected by time (P < 0.01) in both groups (time � trt P = 0.53). Insulin was lower (P < 0.01) in IVAA following LPS [3.1 (2.5—3.9) vs. 4.8 (4.0—5.8) �IU/mL] and decreased over time (P < 0.01) in both groups (time � trt P = 0.94). Plasma EAA (1479 vs. 884 � 83 �M), NEAA (1677 vs. 1361 � 85 �M), and branched-chain AA (BCAA) (1008 vs. 545 � 66 �M) were greater (P < 0.01) in IVAA vs. CTRL at 0 h. Plasma EAA and BCAA decreased over time, reaching a nadir at 8 h, but the effect depended on trt (time � trt P < 0.01). Amino acid infusion did not appear to affect the time-dependent metabolic response to LPS, given the lack of time � trt interactions; however, AA responses were characterized by greater decreases in IVAA over time.

Keywords: transition period, inflammation, glucagon.