Location: Livestock Issues ResearchTitle: Dose response effect of NutriTek on leukocyte functionality and ex vivo cytokine production during a dexamethasone challenge in Holstein steer calves Author
|Sharon, Kate - Texas Tech University|
|Liang, Yu - Texas Tech University|
|Hudson, Rachel - Texas Tech University|
|Yoon, Iikyu - Diamond V Mills, Inc|
|Scott, Mark - Diamond V Mills, Inc|
|Carroll, Jeffery - Jeff Carroll|
|Ballou, Micheal - Texas Tech University|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 4/21/2016
Publication Date: 7/1/2016
Citation: Sharon, K.P., Liang, Y., Hudson, R.E., Yoon, I., Scott, M.F., Sanchez, N.C., Broadway, P.R., Carroll, J.A., Ballou, M.A. 2016. Dose response effect of NutriTek on leukocyte functionality and ex vivo cytokine production during a dexamethasone challenge in Holstein steer calves. Journal of Animal Science Supplement. 94(E-Supplement 5):45, Abstract#102.
Technical Abstract: The objective of this study was to determine the dose response effects of supplementing NutriTek on leukocyte functionality and ex vivo cytokine production during a dexamethasone (DEX) challenge. Holstein steers (125.1 ± 8.16 kg; N = 32) were assigned to treatments including 0, 20, 40, or 60 g/head/d of NutriTek (n = 8). Calves were housed for 21 d in dry lot corrals with 4 calves per pen (2 pens/treatment). Calves were offered ad libitum access to a 50/50 TMR of a commercially available 16% crude protein pelleted grower and chopped alfalfa hay. Treatments were top dressed. The quantity of feed offered and orts were measured daily. After the 21 d adjustment to diets, calves were jugularly catheterized and moved into individual stations (2.13 × 0.76'm) in an environmentally controlled barn and allowed 48 h to adapt before the first DEX injection. Blood samples were collected at -24, -6, 0, 6, 12, 18, 24, 48, and 72 h relative to the first DEX injection. DEX was administered via jugular catheter at 0.1 mg/kg BW at 0, 6, and 12 h. Peripheral blood neutrophil (PMN) concentrations increased (P < 0.001) at 6 h and remained elevated through 72 h in all steers. Neutrophil L-selectin and PMN and monocyte (MONO) oxidative burst (OB) and phagocytosis (PHAG) of an environmental Escherichia coli decreased (P < 0.059) at 6 h in all steers. L-selectin returned to baseline at 72 h while OB and PHAG failed to return to baseline by 72 h. Total leukocytes counts (P < 0.001) and PMN concentrations (P = 0.001) increased linearly with NutriTek dose. PMN L-selectin concentrations did not differ (P = 0.684) among treatments. Oxidative burst intensity in PMN (P = 0.025) and MONO (P = 0.003) increased linearly with NutriTek dose at 72 h, as well as in MONO PHAG intensity (P = 0.004) at 6 h. The percentage of PMN (P = 0.012) and MONO (P = 0.013) that were both PHAG and OB linearly increased with NutriTek dose at 72 h. Ex vivo whole blood lipopolysaccharide stimulated TNF-a concentrations tended to be greater (P = 0.026) in NutriTek steers than control steers at -24 h. Overall, these data demonstrate that the dexamethasone challenge induced severe leukocyte dysfunction, and NutriTek supplementation influenced plasma neutrophil concentrations and may have increased recovery of neutrophil and monocyte function.