|Lebold, Katie -|
|Traber, Maret -|
|Shaffer, Jessica -|
|Block, Stephanie -|
Submitted to: Veterinary Science Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 7, 2013
Publication Date: October 4, 2013
Citation: Elsasser, T.H., Kahl, S., Lebold, K.M., Traber, M.G., Shaffer, J., Li, C., Block, S. 2013. Short-term alpha- or gamma-delta-enriched tocopherol oil supplementation differentially effects the expression of proinflammatory mediators: selective impacts on characteristics of protein tyrosine nitration in vivo. Veterinary Science Development. 3: 20-38. Interpretive Summary: Animals are constantly bombarded with immune challenges that impact health and productivity. Intervention strategies are needed that are effective and do not further impact consumer with drug residues. Vitamins, antioxidant vitamins in particular have been investigated intensely for any potential to improve the outcome of animals to acquired disease stress. Vitamin E, an antioxidant vitamin, has had mixed reviews in regard to how beneficial this is when administered to animals for purposes of improving healthy outcomes from disease stress. We implemented a trial that compared with effects of alpha tocopherol forms of vitamin E with dominant gamma-tocopherol forms for the specific purpose of seeing how these different vitamin forms impacted the development of nitration stress in beef cattle. The results indicated that alpha tocopherol had benefit for this purpose but the effects of the gamma tocopherol, a less expensive product to make and administer, was superior in its ability to decrease adverse effects on the liver to a simulated disease insult (bacterial endotoxin). The data suggest that these preparations may be beneficial if supplemented to animals in advance of exposure to proinflammatory immune states.
Technical Abstract: Protein 3’-nitrotyrosine (pNT) is an established biomarker of nitrosative cell stress in animals challenged with proinflammatory mediators like endotoxin (LPS). We determined that short-term feeding of diets supplemented with a-tocopherol- (a-T -96% a-isomer) or '- and d-enriched mixed tocopherol oils ('-T, ~70 % '-, 20 % d-, 10 % a- isomers) differentially altered liver pNT content of young calves challenged with LPS. Calves fed diets containing supplemented a-T or '-T for five days or no tocopherol supplement (T0E) were challenged with LPS (0.2 µg/kg, iv, E. coli 055:B5). Blood samples for plasma were serially collected before and hourly after LPS and liver biopsy samples collected one day prior to and 24 h after LPS. Alpha- and '-tocopherol content of liver and plasma were measured by HPLC; a-T or '-T feeding increased plasma and liver content of a- and '-tocopherols reflecting their relative abundance in the respective diets. Mean plasma concentrations of Tumor necrosis factor-a (TNF-a), nitrate+nitrite (NOx), and general tissue content of pNT increased after LPS. LPS-mediated increases (mean ± SEM) in TNF-a were not different between diet treatments; both plasma NOx and overall liver pNT responses were attenuated significantly in a-T and '-T versus T0E calves. However, the specific nitration of the mitochondrial Complex V was not only attenuated in a-T and '-T vs T0E but also the mitigating effects of '-T on these nitration events were greater than those of a-T (P<0.04). Results are consistent with the concept that short-term a-T or '-T supplementation can effectively decrease proinflammatory liver pTN after LPS; some molecular nitration targets may be better protected with prophylactic supplementation of oils particularly enriched with the '-,d-isomers.