Evaluation of the innate immune response of Angus heifers with genetic marker variation for intramuscular fat deposition following a lipopolysaccharide challenge

• Published in: Livestock science Vol. 188; pp. 103 - 110
• Main Authors: Buntyn, J.O., Carroll, J.A., Smith, T., Rivera, J.D., Sanchez, N.C. Burdick, Broadway, P.R., Falkenberg, S.M., Schmidt, T.B.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2016
• Subjects: Acute phase response; Cattle; Cytokines; Marbling; Quantitative trait loci; Quantitative trait loci; Cytokines; Acute phase response; Cattle; Marbling
• ISSN: 1871-1413; 1878-0490
• DOI: 10.1016/j.livsci.2016.04.013

This study evaluated the effect of genetic selection for markers related to marbling deposition in Angus heifers on the immune response following a lipopolysaccharide (LPS) challenge. Fall-born heifers (n=19; ~7 months of age, 274±24kg) with genetic variation for marbling were utilized including 10 heifers with no genetic markers (No-MVP) and 9 heifers with ≥1 markers (1+MVP). Genotypic variation for quantitative trait loci QG1 and QG2 heifers was determined. Twenty-four hour (h) prior to the LPS challenge, heifers were fitted with jugular catheters and vaginal temperature (VT) monitoring devices. Temperature monitoring devises were programed to record VT in 1min intervals. On day (d) 0, 2h prior to LPS challenge and 8h post challenge, serum was collected in 0.5h intervals (0800–1800h). Serum was also collected at 12, 16, 20, and 24h post LPS challenge. The LPS challenge was administered to the heifers at 1000h via intravenous bolus (0.5μg/kg BW). Serum was analyzed for cortisol, TNF-α, IL-6, IFN-γ, and haptoglobin (HAPT). A treatment×time interaction existed (P≤0.001) for VT; prior the LPS challenge, VT was similar. Vaginal temperature was elevated from 6 to 21h post-LPS in 1+MVP compared to No-MVP. A treatment×time interaction (P=0.02) was observed for IFN-γ. Prior to the LPS challenge, IFN-γ concentrations were similar between the two groups. However, 3.5–7h post-LPS concentrations of IFN-γ were greater (P≤0.05) for 1+MVP compared to No-MVP. There was no treatment effect (P≥0.17) for cortisol, TNF-α or IL-6. A treatment effect (P=0.02) was observed for HAPT; 1+MVP had decreased HAPT compared to No-MVP. Overall, results suggest that heifers selected based upon genetic markers for marbling may have an altered immune in response when challenged with LPS.
•Heifers with genetic markers for marbling may have an altered immune in response to an LPS challenge.•Heifers possessing GeneStar® MVP QTL's, had an increase in vaginal temperature following LPS challenge.•Heifers with 1+MVP may have greater energy reserves allowing a sustained increase in body temperature.