|Carroll, Jeffery - Jeff Carroll|
|WELSH JR, TOM|
Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 12/15/2008
Publication Date: 2/2/2009
Citation: Carroll, J.A., Hulbert, L.E., Burdick, N., Caldwell, L., Dailey, J.W., Ballou, M., Vann, R., Welsh Jr, T., Randel, R. 2009. Bovine exhibit a sexually dimorphic innate immune response following an endotoxin challenge[abstract]. Annual meeting of the Southern Section of American Society of Animal Science in Atlanta, GA, on Jan 31 - Feb 4, 2009. Journal of Animal Science. 87(Supplement 2):21. Abstract #64.
Technical Abstract: Sexually dimorphic responses to various stressors have been previously reported for rodents and humans. However, limited research has addressed whether innate immune responses are sexually dimorphic in cattle. The objective of this study was to investigate whether beef cattle exhibit a sexually dimorphic innate immune response following an endotoxin challenge. Twelve purebred Brahman calves (6 bulls and 6 heifers; 269±11.7 kg) were fitted with a) rectal temperature (RT) devices that recorded RT at 1-minute intervals for 24 hours; and b) indwelling jugular catheters. The next day blood samples were collected at 30-minute intervals from -4 to 8 hours relative to an i.v. infusion of lipopolysaccharide (LPS; 0.25 micrograms/kg BW) at 0 hour. Serum was stored at -80 deg C until analyzed for tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6) and interferon gamma (IFN-gamma). RT data were summed into 12-minute intervals prior to statistical analysis. As expected, RT increased rapidly in both groups; however, a Time X Sex interaction (P<0.04) was observed such that RT peaked sooner in heifers (40.7±0.22 deg C at 216 minutes) as compared to bulls (40.3±0.6 at 252 minutes) following the LPS challenge. Following peak values, RT continued to decline in both groups; however, RT returned to baseline values earlier in heifers as compared to bulls (768 minutes and 1152 minutes post-LPS, respectively). For each of the cytokines, a Time X Sex interaction was evident (P<0.01). Peak TNF-alpha concentrations were observed at 1 and 1.5 hours post-LPS for bulls and heifers, respectively, with heifers having a lower TNF-alpha response post-LPS (P<0.01). Peak IL-6 concentrations occurred at 3 and 3.5 hours post-LPS for bulls and heifers, respectively, with heifers having a lower IL-6 response post-LPS. For IFN-gamma, post-LPS concentrations tended to be lower in heifers as compared to bulls (P<0.07). Collectively, these data suggest that heifers may be more adept at coping with and recovering from an immune challenge as compared to bull calves. To our knowledge, these are the first data to demonstrate a sexually dimorphic innate immune response in the bovine following an endotoxin challenge.