Oxidative stress and antioxidant status in intensely exercising horses administered nutraceutical extracts.
BACKGROUND
Many nutraceuticals are used as equine supplements without their efficacy having been scientifically tested. Black tea, cranberries, orange peel and ginger are a few of those nutraceuticals that warrant further study.


OBJECTIVE
To test the effects of single doses of black tea, cranberry, orange peel and ginger extract on markers of oxidative stress and antioxidant status following exercise in horses.


METHODS
In Study 1, 9 mature, healthy but unfit Standardbred mares were administered 2 l of a control (water), orange peel extract (30 g extract) or decaffeinated black tea extract (28 g extract). In Study 2 the same mares were administered 2 l of a control (water), cranberry extract (30 g extract) or ginger extract (30 g extract). In each study, mares were given the extracts via nasogastric tube 1 h before performing a graded exercise test (GXT), in a randomised crossover design with at least 7 days between GXTs. Blood samples were collected at rest, at fatigue, and 1 and 24 h post exercise and analysed for lipid hydroperoxides (LPO), total glutathione (GSH-T), glutathione peroxidase (GPx), α-tocopherol (TOC), β-carotene (BC) and retinol. Data were statistically analysed using a repeated measures ANOVA.


RESULTS
In Study 1 there was no effect of treatment for LPO, GSH-T, GPx, TOC or BC. Retinol was higher for both tea (P = 0.0006) and water (P = 0.004) than for orange peel. In Study 2 there was no treatment effect for LPO, GPx, GSH-T, RET, BC or TOC.


CONCLUSIONS
The results show that a single dose of various nutraceuticals in exercising horses do not produce an effect on either oxidative stress or antioxidant status and further investigation is needed as to whether long-term supplementation would enhance these effects.
Department of Animal Science, Equine Science Center, Rutgers, the State University, New Jersey, USA.
D N
DN
Smarsh
N
N
Liburt
J
J
Streltsova
K
K
McKeever
C A
CA
Williams
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D018592:Cross-Over Studies; D019587:Dietary Supplements / Q000032:analysis; D005260:Female; D006736:Horses / Q000097:blood / Q000502:physiology*; D018384:Oxidative Stress / Q000187:drug effects*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D014867:Water / Q000737:chemistry*
D000975:Antioxidants; D010936:Plant Extracts; D014867:Water