|Reuter, Ryan -|
|Spiers, Don -|
|Arthington, John -|
Submitted to: Domestic Animal Endocrinology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 8, 2011
Publication Date: October 5, 2011
Citation: Carroll, J.A., Burdick, N.C., Reuter, R., Chase, C.C., Spiers, D., Arthington, J., Coleman, S.W. 2011. Differential acute phase immune responses by Angus and Romosinuano steers following an endotoxin challenge. Domestic Animal Endocrinology. 41(4):163-173. Interpretive Summary: A collaborative study was conducted involving scientists from the Livestock Issues Research Unit, the USDA-ARS SubTropical Agricultural Research Station in Brooksville, Florida, the University of Missouri, the University of Florida’s Range Cattle Research and Education Center at Ona, and The Samuel Roberts Nobel Foundation to elucidate potential differences in the innate immune response of two diverse breeds of Bos taurus cattle following an intravenous challenge with an endotoxin. Previous studies have demonstrated the potential for genetic differences associated with immune responses in various breeds of cattle. However, there is limited evidence of an effect of breed on the acute innate immune response to a pathogen. Therefore, the specific objective of this study was to evaluate potential differences in the acute phase immune response between Angus and Romosinuano steers following an i.v. bolus injection of E. coli lipopolysaccharide (LPS). Results from this study demonstrated that while steers from both breeds responded to the LPS challenge, there were significant differences in the physiological, stress, and immune responses. Based on indicators of the stress response, the topically adapted Romosinuano steers appear to be more adept at coping with the endotoxin exposure, and may experience less stress overall. However, based upon the pro-inflammatory cytokine responses, Angus steers may be more likely to return to homeostasis quicker from the inflammatory insult compared to Romosinuano steers. Conversely, the Romosinuano steers may be more adept at clearing invading pathogens. Whether or not the differences observed in the current study between the Angus and Romosinuano steers would affect the resistance to, or recovery from a live bacterial challenge warrants further investigation. 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 elucidate other physiological/immunological mechanisms that contribute to differences in productivity, heat tolerance, disease resistance, and longevity among cattle breeds. The results of this research will be of particular interest to beef cattle producers, veterinarians managing the health of cattle, and scientists, whether from industry, academia, or industry, working in the area of beef cattle production, health, and well-being.
Technical Abstract: Our primary objective was to evaluate potential genetic differences between two diverse Bos taurus breeds (Angus (AG) and Romosinuano (RO)) in response to an endotoxin. The RO is a tropically adaptive 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 degrees C) and then fitted with indwelling jugular catheters and rectal temperature (RT) recording devices one day prior to the endotoxin challenge. The following day, blood samples were collected at 30-min intervals from -2 to 8 h and RT was measured continuously at 1-min intervals throughout the study. At time 0, all steers received an i.v. bolus injection of lipopolysaccharide (LPS; 2.5 micrograms/kg BW). Serum samples were stored at -80 degrees C until analyzed for cortisol, pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF), interleukin-1 beta (IL-1), IL-6, and interferon gamma (IFN)), and acute phase proteins (serum amyloid A, acid soluable protein, ceruloplasmin, and alpha-acid glycoprotein). Data were analyzed using an ANOVA specific for repeated measures. Rectal temperatures increased in both breeds within 1 h post-LPS with RO producing a greater increase in RT than AG steers (P < 0.001). Serum cortisol and TNF increased (P < 0.01) in both groups within 1 h following the LPS challenge. For cortisol, an overall breed effect (P < 0.02) was detected such that the cortisol 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 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 the innate immune response between two diverse Bos taurus breeds and may aid in our ability to elucidate other physiological/immunological mechanisms that contribute to differences in productivity, heat tolerance, disease resistance, and longevity among cattle breeds.