Location: Livestock Issues ResearchTitle: Enhancement of the acute phase response to lipopolysaccharide in feedlot steers supplemented with OmniGen-AF Author
|Buntyn, Joe - University Of Nebraska|
|Carroll, Jeffery - Jeff Carroll|
|Wistuba, Troy - Prince Agri Products, Inc|
|Dehaan, Kevin - Prince Agri Products, Inc|
|Sieren, Sara - University Of Nebraska|
|Jones, Steven - University Of Nebraska|
|Schmidt, Ty - University Of Nebraska|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2014
Publication Date: 7/25/2014
Citation: Sanchez, N.C., Buntyn, J.O., Carroll, J.A., Wistuba, T., Dehaan, K., Sieren, S.E., Jones, S.J., Schmidt, T.B. 2014. Enhancement of the acute phase response to lipopolysaccharide in feedlot steers supplemented with OmniGen-AF. Journal of Animal Science Supplement. 92(E-Suppl. 2):37-38. Abstract #73.
Technical Abstract: This study was designed to determine the effect of supplementing feedlot steers with OmniGen-AF on the acute phase response to a lipopolysaccharide (LPS) challenge. Steers (n = 18; 270 ± 5 kilograms body weight) were separated into two treatment groups (n=9/treatment): one group was fed a standard receiving diet (Control, Cont) and the other group was fed the same receiving diet supplemented with OmniGen-AF at 4 grams/45.4 kilograms body weight for 29 days (OmniGen-AF). On day 27 steers were fitted with indwelling jugular cannulas and rectal temperature (RT) monitoring devices and placed in individual stalls. On day 28, steers were challenged intravenously with LPS (0.5 micrograms/kilograms body weight at 0 hour). Sickness behavior scores (SBS) and two whole blood samples were collected at 30-minute intervals from -2 to 8 hours relative to the challenge at 0 hour. One vacutainer containing EDTA was collected for complete blood cell count (CBC) analysis, and the second was collected in 9-mL monovette serum tube; after collection serum was isolated and stored at -80C until analyzed for cortisol and cytokine concentrations. Rectal temperature, SBS, and cortisol were affected by time (P<0.001). Prior to the challenge, RT was greater (P<0.001) in Cont steers (39.31±0.03C) than OmniGen-AF steers (39.14±0.03C). Therefore, post-challenge RT was analyzed as the change in response from baseline values. The change in RT relative to baseline values increased (P<0.001) in both groups in response to LPS challenge, but was not affected by treatment (P=0.49). Sickness behavior scores increased (P<0.001) after LPS challenge and tended (P=0.09) to be greater in Control (1.57±0.02) than OmniGen-AF steers (1.51±0.02). Cortisol concentrations were affected by treatment (P=0.005) and time (P<0.001). For both groups, cortisol increased (P<0.001) in response to LPS challenge. Cortisol was greater in Cont (25.2±0.9 nanograms/mililiter) than OmniGen-AF steers (25.5±0.9 nanograms/mililiter). White blood cell and lymphocyte concentrations were greater (P=0.004) in Cont than OmniGen-AF steers throughout the study. Neutrophils were decreased (P = 0.04) in Cont steers (0.7±0.2 1000/microliter) compared to OmniGen-AF steers (1.3±0.2 1000/microliter) prior to the LPS challenge. There was a treatment (P=0.02) and time (P<0.001) effect for tumor necrosis factor-alpha (TNFa) and interferon-gamma (IFNg). Specifically, TNFa and IFNg concentrations increased (P<0.001) in response to LPS challenge. Furthermore, concentrations of TNFa and IFNg were decreased in (P=0.02) in Cont steers compared to OmniGen-AF steers. These data suggest that OmniGen-AF supplementation served to prime the immune system prior to the LPS challenge, allowing for an enhanced response to LPS challenge.