ARS | Publication request: Use of a lipopolysaccharide (LPS) challenge to evaluate the innate immune response of Angus heifers with genotypic differences in GeneSTAR markers for Intramuscular fat deposition

Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: November 14, 2011
Publication Date: July 15, 2012
Citation: Buntyn, J., Carroll, J.A., Smith, T., Falkenberg, S., Rivera, J., Sanchez, N.C., Schmidt, T. 2012. Use of a lipopolysaccharide (LPS) challenge to evaluate the innate immune response of Angus heifers with genotypic differences in GeneSTAR markers for Intramuscular fat deposition [abstract]. Journal of Animal Science 90:13 (E-Suppl. 2). Abstract #39.

Technical Abstract: Intramuscular fat can serve as an energy reserve for cattle during an immune challenge, thus cattle with a genotypic variation in DNA markers (DNAm) for IMF may have an altered response to an immune challenge. In a previous study with Angus heifers with or without DNAm for IMF which were challenged with lipopolysaccharide, there was variation in the immune response. The objective of this study was to re-evaluate the innate immune response of Angus heifers selected for genotypic variation in intramuscular fat deposition (IMFD). Genotypic variation (QG1 and QG2) in heifers was determined by presence or absence of DNAm for IMFD. Nineteen heifers (274 ± 24 kg) were sorted into two treatment groups based upon DNAm; heifers with no DNAm for IMFD (n=9; NoIMFD), and heifers with one or more DNAm for IMFD (n=10; IMFD). Prior to challenge (24 hrs), indwelling jugular catheters and indwelling vaginal thermometers were inserted. Blood samples were collected at 30-min intervals and vaginal temperatures (VT) at 1-min intervals from -2 to 8 h relative to the immune challenge (LPS: 0.5 ug/kg BW) at time 0. Heifers with IMFD displayed greater (P < 0.05) VT temperature 6-9 hrs post LPS challenge compared to heifers with NoIMFD (39.57 and 39.22±0.15 deg C, respectively). Heifers in the NoIMFD group had greater (P < 0.05) concentrations of IFN-gamma 4 hr post-LPS compared to IMFD heifers (701.1 and 324.3±175 ng/ml, respectively). No differences (P>0.05) were observed between groups of heifers for IL-6 concentrations. Heifers within the IMFD group had a greater (P<0.05) concentration of TNF alpha at 1.5-2 hr post-LPS compared to NoIMFD heifers, while NoIMFD heifers had a greater (P<0.05) concentration of haptoglobin at 20-24 hr post-LPS. Coupled with the results of the 2009 trial, these results suggest that there is a difference to an LPS challenge in heifers with genotypic variation in intramuscular fat deposition.