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Effects of Dietary Selenium and Training on Oxidative Stress in Young Horses
Author(s) -
White SH,
Warren LK
Publication year - 2014
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.12267_100
Subject(s) - glutathione peroxidase , oxidative stress , selenium , medicine , horse , antioxidant , endocrinology , analysis of variance , lipid peroxidation , zoology , chemistry , superoxide dismutase , biochemistry , biology , paleontology , organic chemistry
Exercise training can enhance antioxidant status, but it is unknown whether selenium supplementation can further improve antioxidant defenses. Methods A merican Q uarter H orse yearlings (n = 20; mean ± SE 18 ± 0.2 months) balanced with regard to age and sex were randomly assigned to four dietary S e and training treatments for 14 weeks: 0.1 mg S e/kg DM with (n = 5) or without (n = 5) training or 0.3 mg S e/kg DM with (n = 5) or without (n = 5) training. Trained horses were exercised 4 d/wk for 30 min/d. At wk 14, all horses underwent a 2‐hr, 27.5 km submaximal exercise test ( SET ). Blood samples and biopsies of the gluteus medius were obtained before and after training and in response to the SET . Serum S e, glutathione peroxidase ( GPx ) activity in whole blood and muscle, and plasma lipid hydroperoxides ( LPO ) were evaluated. Data were analysed using a mixed model ANOVA with repeated measures. Results Serum S e was higher (P = 0.02) at wk 14 in trained horses receiving 0.3 than 0.1 mg S e/kg, but was unaffected by diet in untrained horses. Muscle GPx activity was unchanged after 14‐weeks of S e and training, but in response to the SET , muscle GPx was higher (P = 0.05) in trained than untrained horses. An effect of training*time (P = 0.008) was noted for whole blood GPx , reflecting greater (P = 0.01) activity in trained than untrained horses immediately after the SET . Plasma LPO was not influenced by dietary S e, but increased (P<0.0001) in untrained horses immediately after the SET while remaining unchanged in trained horses. Conclusions Training appears to mitigate oxidative damage in response to prolonged exercise in young horses. Although trained horses responded to a higher level of dietary S e, it showed no clear advantage for reducing oxidative stress. Ethical Animal Research This project was approved by the Institute of Food and Agricultural Sciences Animal Care Committee at the U niversity of F lorida (approval number 016‐12ANS). Sources of funding: Partial financial support of this project was provided by A lltech, N icholasville, KY , USA . Competing interests: none.