|Spiers, Don - UNIV OF MISSOURI - COLUMB|
|Reuter, Ryan - TEXAS TECH UNIVERSITY|
Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: November 3, 2006
Publication Date: February 1, 2007
Citation: Carroll, J.A., Chase, C.C., Coleman, S.W., Riley, D.G., Spiers, D., Dailey, J.W., Reuter, R. 2007. Angus and Romosinuano steers exhibit differential acute phase responses following an endotoxin challenge [abstract]. Journal of Animal Science. 85(Suppl. 2):26-27. Technical Abstract: Our primary objective was to elucidate the acute phase response in cattle while evaluating potential genetic differences between two diverse Bos taurus breeds [Angus (AG) and Romosinuano (RO)] in response to an endotoxin challenge. The Romosinuano is a tropically adapted Bos taurus breed developed in the Sinú valley of northern Colombia. Eighteen steers (n = 9 steers/breed; 299.4 + 5.2 Kg BW) were acclimated to environmentally controlled chambers maintained at thermoneutrality (19.7 deg C) and then fitted with an indwelling jugular catheter one day prior to the endotoxin challenge. The following day, blood samples were collected at 30-min intervals from -2 to 8 h. At time 0, all steers received an i.v. injection of lipopolysaccharide (LPS; 2.5 ug/Kg BW). Serum samples were stored at -80 deg C until analyzed for cortisol (CS) and pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF), interleukin-1 beta (IL-1), IL-6, and interferon-gamma (IFN)]. Data were analyzed using an ANOVA analysis specific for repeated measures. Serum CS and TNF increased (P < 0.01) in both groups within 1 h following the LPS challenge. For CS, an overall breed effect (P < 0.02) was detected such that the CS response was greater in the AG steers as compared to the RO steers. A breed x time interaction (P < 0.01) was observed for TNF such that the response was delayed and extended in the RO steers as compared to the AG steers. At 2 and 2.5 h post-LPS, TNF concentrations were greater (P < 0.03) in RO steers compared to AG steers. For IL-1, a breed x time interaction (P < 0.04) was also observed. At 3 h post-LPS, IL-1 concentrations were greater (P < 0.01) in RO steers as compared to AG steers, and demonstrated a more pronounced biphasic response. Serum IL-6 and IFN increased (P < 0.01) in a similar manner in both groups following the LPS challenge. To our knowledge, these are the first data to demonstrate differences in innate immunity between two diverse Bos taurus breeds and may aid in our ability to further elucidate other physiological/immuno-logical mechanisms that contribute to differences in productivity, heat tolerance, disease resistance, and longevity among cattle breeds.