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Whole blood glutathione peroxidase activity in Standardbred broodmares supplemented with vitamin E and selenium.
Abstract: The objective of this study was to determine the effect of either oral supplementation of sodium selenite and alpha-tocopherol or intramuscular administration of a commercial preparation of selenium (Se) and vitamin E to Standardbred broodmares with low (21.0 ± 18.1 IU/g Hb) whole blood glutathione peroxidase (GPx) activity. Ten mares received 3 weekly intramuscular (IM) doses, whereas 9 mares were orally supplemented daily for 10 wk. Blood samples were collected jugular venipuncture and the whole blood GPx activity was measured at each sampling time for the 32-week period. Both oral and intramuscular administration resulted in a marked increase in whole blood GPx activity in both groups of mares. L’objectif de cette étude était de déterminer l’effet d’une supplémentation orale en sélénite de sodium et en alpha-tocophérol, ou d’une administration intramusculaire d’une préparation commerciale de sélénium (Se) et de vitamine E, chez des juments poulinières Standardbred présentant une faible activité de glutathion peroxydase (GPx) sanguine (21,0 ± 18,1 UI/g Hb). Dix juments ont reçu 3 injections intramusculaires (IM) hebdomadaires, tandis que 9 autres ont reçu une supplémentation orale quotidienne pendant 10 semaines. Des échantillons de sang ont été prélevés par ponction de la veine jugulaire et l’activité de la GPx sanguine a été mesurée à chaque prélèvement pendant les 32 semaines de l’étude. L’administration orale autant qu’intramusculaire, a entraîné une augmentation significative de l’activité de la GPx sanguine dans les deux groupes de juments.(Traduit par Docteur Serge Messier).
Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.
Publication Date: 2026-01-01 PubMed ID: 41585003PubMed Central: PMC12825818 The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
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Overview
- This study investigated how supplementing Standardbred broodmares with vitamin E and selenium, either orally or via intramuscular injection, affected their whole blood glutathione peroxidase (GPx) activity when initially low.
- The researchers measured the changes in GPx activity over 32 weeks and found both supplementation methods significantly increased enzyme activity in the mares.
Background
- Glutathione peroxidase (GPx) is an important antioxidant enzyme that protects cells from oxidative damage by neutralizing harmful peroxides.
- Selenium (Se) and vitamin E (alpha-tocopherol) are essential nutrients that serve as cofactors and antioxidants, supporting GPx activity and thus overall oxidative protection.
- Broodmares, especially those with initially low GPx activity, may benefit from supplementation to improve antioxidant defenses and possibly enhance health and reproductive performance.
Objectives
- To assess the effect of oral versus intramuscular supplementation of selenium and vitamin E on whole blood GPx activity in Standardbred broodmares with low initial GPx.
- To compare the efficacy and duration of the different supplementation routes over 32 weeks.
Methods
- Subjects: 19 Standardbred broodmares with low baseline GPx activity (~21.0 ± 18.1 IU/g Hb).
- Groups:
- 10 mares received 3 weekly intramuscular (IM) injections of a commercial preparation containing selenium and vitamin E.
- 9 mares received daily oral supplementation of sodium selenite (selenium source) and alpha-tocopherol (vitamin E) for 10 weeks.
- Sampling: Blood samples were collected repeatedly via jugular venipuncture over a total period of 32 weeks.
- Measurements: Whole blood GPx activity was measured at each sampling time to monitor changes.
Results
- Both supplementation routes—oral and intramuscular—produced a marked and significant increase in whole blood GPx activity compared to baseline levels.
- The increase in GPx activity was sustained during the supplementation period, indicating improved antioxidant enzyme function.
- This suggests that both supplementation methods effectively raised selenium status, leading to enhanced GPx enzyme activity.
Conclusion and Implications
- Supplementing Standardbred broodmares that have low GPx activity with vitamin E and selenium can substantially improve their antioxidant enzyme levels.
- Both oral daily supplementation for 10 weeks and three weekly intramuscular injections are effective methods to increase GPx activity.
- This elevation of GPx activity may help protect broodmares from oxidative stress, potentially improving their health and reproductive outcomes.
- Veterinarians and equine nutritionists may consider these supplementation protocols for broodmares at risk of selenium or vitamin E deficiency to enhance antioxidant status.
Cite This Article
APA
Baird JD, Arroyo LG, Lumsden JH.
(2026).
Whole blood glutathione peroxidase activity in Standardbred broodmares supplemented with vitamin E and selenium.
Can J Vet Res, 90(1), 25-29.
Publication
Researcher Affiliations
- Department of Clinical Studies (Baird, Arroyo) and Department of Pathobiology (Lumsden), Ontario Veterinary College, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1.
- Department of Clinical Studies (Baird, Arroyo) and Department of Pathobiology (Lumsden), Ontario Veterinary College, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1.
- Department of Clinical Studies (Baird, Arroyo) and Department of Pathobiology (Lumsden), Ontario Veterinary College, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1.
MeSH Terms
- Animals
- Female
- Glutathione Peroxidase / blood
- Glutathione Peroxidase / metabolism
- Glutathione Peroxidase / genetics
- Dietary Supplements
- Selenium / administration & dosage
- Selenium / pharmacology
- Vitamin E / administration & dosage
- Vitamin E / pharmacology
- Horses / blood
- Administration, Oral
- Injections, Intramuscular / veterinary
- Sodium Selenite / administration & dosage
- Sodium Selenite / pharmacology
- Diet / veterinary
- Animal Feed / analysis
- Animal Nutritional Physiological Phenomena
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