Submitted to: American Dairy Science Association Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 7/25/2001
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: The effect of intravenous lipopolysaccharide (LPS; E. coli O11:B4) infusion on liver metabolism in 12 multiparous midlactation cows (150-220 DIM) was investigated. A covariate liver sample was obtained via percutaneous trochar biopsy 7 d prior to LPS infusion. Liver slices were used in vitro to determine hepatic capacities for conversion of [1- 14C]propionate, [1-14C]alanine, and [1-14C](L+)-lactate to CO2. Hepatic capacities for conversion of [1-14C]palmitate to CO2, acid soluble products and stored esterified products also were determined. Seven days later, cows were intravenously infused with either 0 (n=6), 1.0 (n=4), or 2.0 (n=2) ug LPS/kg BW dissolved in 100 ml physiological saline during a 100-min infusion. Saline infused cows were pair-fed with LPS-infused cows during the infusion period to eliminate effects of feed intake with LPS treatment. Liver was biopsied at 4.5 h after the beginning of infusion and metabolic incubations were conducted as described for covariate samples. Differences in the capacities of liver from control and LPS- infused cows to convert [1-14C]palmitate to CO2, acid soluble products, and stored esterified products were not significant (P more than 0.20). However, LPS infusion tended to increase the capacity of liver to convert [1-14C]propionate (4.19, 4.23, 6.07 umol/h x g wet weight; P less than 0.12) and [1-14C](L+)-lactate (0.66, 0.98, 1.00 umol/h x g wet weight; P less than 0.06) to CO2 for 0, 1.0 and 2.0 ug LPS/kg BW, respectively. Differences in hepatic capacity to convert [1-14C]alanine to CO2 were not significant (P more than 0.20). These data suggest that aspects of hepatic carbohydrate metabolism in lactating dairy cows are affected by the inflammatory response elicited by LPS infusion.