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Effects of LPS administration and subsequent nutrient restriction on metabolism in lactating dairy cows.

S. Rodriguez-Jimenez


Effects of LPS administration and subsequent nutrient restriction on metabolism in lactating dairy cows.
S. Rodriguez-Jimenez*, E. A. Horst, E. J. Mayorga, M. A. Abeyta, B. M. Goetz, S. Carta, L. H. Baumgard. Iowa State University Ames, IA.

Objectives were to evaluate the effects of repeated LPS exposure and subsequent feed restriction (FR) on metabolism in lactating cows. Cows (631 � 16 kg BW; 124 � 15 DIM) were enrolled in a study consisting of 3 experimental periods (P); during P1 (5d) cows were ad libitum-fed and baseline data were obtained. During P2 (7d), cows were assigned to 1 of 2 treatments: 1) saline-infused and pair-fed (PFFR; 5 mL saline on d1, 3, and 5; n = 6) or 2) LPS-infused and ad libitum-fed (LPSFR; 0.2, 0.8, and 1.6 �g LPS/kg BW on d1, 3, and 5, respectively; n = 6). During P3 (7d), all cows were feed restricted to 50% of P1 feed intake. On d3 of P3, LPSFR cows received an LPS bolus (0.8 �g LPS/kg BW) whereas PFFR cows received saline. Blood samples were obtained on d 1 and 3 of P1, and on d 1, 3, 5, and 7 of P2 and P3. Ketone tolerance tests (KTT) were performed on d3 of P1, and on d 2 and 6 of P2 and P3. Data were analyzed using PROC MIXED of SAS. Relative to P1, insulin decreased in both treatments during P2 and P3 (P < 0.01). Relative to PFFR, insulin from LPSFR increased overall during P2 (2.5-fold; P < 0.01) and transiently on d3 of P3 (2.6-fold; P < 0.01). Circulating NEFA from PFFR increased markedly from d 1 to 3 of P2 (3.4-fold relative to P1; P < 0.01) and then slowly decreased, whereas levels remained unchanged in LPSFR related to P1. Overall in P2, circulating NEFA from PFFR cows increased (63%) relative to LPSFR (P < 0.01). During P3, NEFA levels did not differ across treatments but were increased in both PFFR and LPSFR cows relative to P1 (P < 0.01). No treatment differences were detected for circulating BHB during P2, however, concentrations increased (18%) on d 5 of P3 in PFFR cows while in LPSFR remained similar (P = 0.07) relative to P1. In response to the KTT, BHB area under the curve decreased in LPSFR relative to PFFR cows on d 2 and 6 of both P2 and P3 (30, 47, 30, and 13% respectively; P < 0.01). In conclusion, inflammation caused hyperinsulinemia and increased BHB clearance rates.

Keywords: immune activation, ketone tolerance test.

Biography: Sonia is a second year PhD student working under the direction of Dr. Lance Baumgard