ARS | Publication request: Effects of short-term tocopherol (T) feeding on nitric oxide production and protein nitration following endotoxin (LPS) challenge in beef calves

Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: April 21, 2010
Publication Date: July 14, 2010
Citation: Kahl, S., Elsasser, T.H., Li, C., Lebold, K., Traber, M., Block, S. 2010. Effects of short-term tocopherol (T) feeding on nitric oxide production and protein nitration following endotoxin (LPS) challenge in beef calves. Journal of Animal Science. 88(E-Suppl. 2):590.

Technical Abstract: Posttranslational protein tyrosine nitration (pNT) contributes to functional tissue damage during pro-inflammatory stress. With regard to chemical reactivity, a-T has a greater antioxidant potential while '-T has greater ability to inactivate reactive oxynitrogen species potentially involved in pTN formation. Our objective was to determine the effects of 5-d feeding of supplemental a-T (A, Novatol™ 1490, ADM; T content (%): a = 98.2, ' < 1) or '-T (G, Decanox™ MTS-90 G, ADM; T content (%): a = 10, ' = 69) on the generation of key biomarkers of pNT during pro-inflammatory episodes initiated with LPS (0.25 µg/kg BW, i.v., E. coli 055:B5). Beef calves (n = 21; 211 ± 6 kg) were group penned in equal numbers across three test diet assignments: control (C, no supplement), A, or G. A growth diet was fed daily in all pens at 90% mean group ad libitum intake and top-dressed with a premix containing the treatments (daily intake/calf: Novatol™ = 1.25 g; Decanox™ = 3.85 g). Blood samples were obtained at 0, 7, and 24 h, and liver biopsy samples at -24 and 24 h relative to LPS injection. At LPS challenge, liver ['-T] was: G > C or A (P < 0.01) while [a-T] was: A > G > C (P < 0.01). In all calves mean plasma concentrations of xanthine oxidase (XO, a superoxide anion producer, P<0.05) and nitrate+nitrite (NOx, an estimate of NO production, P<0.01) increased after LPS. For XO no differences were observed between treatments but the increase in NOx was attenuated in both A (45.7%) and G (46.3%) as compared to C (P < 0.05). The generation of pTN (measured by quantitative immunohistochemical localization of nitrotyrosine pixel density) 24 h after LPS was lower in A (24.4%) and G (27.4%) than in C (P < 0.01). Results indicate that a 5-d feeding of vitamin E isoforms differentially affects the generation of mediators of pTN but both significantly decrease overall pTN.