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Equine veterinary journal2020; 53(3); 542-548; doi: 10.1111/evj.13294

The effect of diet-induced obesity and pasture on blood pressure and serum cortisol in Standardbred mares.

Abstract: Obesity is associated with insulin resistance, vascular dysfunction and altered cortisol metabolism both in humans and in horses. Objective: Evaluate the effect of weight gain induced by a haylage diet low in nonstructural carbohydrates (NSC) on insulin sensitivity, blood pressure and serum cortisol concentrations. Methods: In vivo experiment. Methods: Nine adult Standardbred mares fed a fat supplemented haylage diet at 250% of the horses' daily metabolisable energy requirements for 22 weeks. Horses were then turned out on pasture for 4 weeks. Insulin sensitivity (SI ) was measured before and after weight gain and after 4 weeks of pasture using the euglycemic hyperinsulinaemic clamp (EHC) method. Body condition score (BCS), blood pressure and serum cortisol were monitored throughout the study. All data were analysed using the linear mixed model procedure. Values of P  7). Mean arterial blood pressure (MAP) increased during the weight gain period and was significantly higher than initial values at the end of the weight gain period (78 ± 3 mm Hg vs 92 ± 3 mmHg). MAP remained increased on pasture (93 ± 3 mmHg). SI was unaffected by weight gain 0.9 ± 0.1 vs 1.0 ± 0.1 ([mg/kg/min × 10 ]/[µIU/mL × mmol/L])) but improved after pasture (1.6 ± 0.1 ([mg/kg/min × 10 ]/ [mU/L]). Serum cortisol concentrations increased during the weight gain period (80 ± 9 nmol/L vs 112 ± 9 nmol/L) and remained increased during pasture. Conclusions: Limited number of horses and no control group. Conclusions: Obesity was associated with a linear increase in blood pressure and an increase in serum cortisol that was not associated with insulin sensitivity.
Publication Date: 2020-07-04 PubMed ID: 32483866DOI: 10.1111/evj.13294Google Scholar: Lookup
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  • Journal Article

Summary

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The research paper investigates how diet-induced obesity affects blood pressure and serum cortisol levels in adult Standardbred mares. The study found that obesity led to increased blood pressure and cortisol levels regardless of insulin sensitivity.

Objective and Methodology

The research aimed to study how weight gain, triggered by a low nonstructural carbohydrate haylage diet, influences insulin sensitivity, blood pressure, and serum cortisol levels. This in-vivo experiment was conducted on nine adult Standardbred mares who were fed a fat-supplemented haylage diet. These horses consumed 250% of their daily metabolizable energy needs for 22 weeks. Following this period, they spent 4 weeks on pasture.

Measurements and Results

  • Insulin sensitivity was gauged before and after the weight gain period, and again after the pasture period, using the euglycemic hyperinsulinaemic clamp method.
  • The horses’ body condition score, blood pressure, and serum cortisol were monitored throughout the study. All the horses involved in the study became obese after the weight gain period, with blood pressure increasing significantly during this time. This increased blood pressure maintained when the horses were on the pasture.
  • Contrary to expectation, insulin sensitivity was unaffected by the weight gain but improved after the pasture period.
  • Finally, serum cortisol levels increased during the weight gain period and remained high while the horses were on pasture.

Conclusion

Despite the limitations of the study which includes a small sample size of nine horses and the absence of a control group, it concluded that obesity in horses leads to increased blood pressure and serum cortisol levels, irrespective of insulin sensitivity. The researchers suggest that these phenomena hold true regardless of the impact on insulin sensitivity. This finding points to a clear link between diet-induced obesity and increases in both blood pressure and cortisol levels.

Cite This Article

APA
Nostell K, Lindåse S, Winqvist E, Bröjer J. (2020). The effect of diet-induced obesity and pasture on blood pressure and serum cortisol in Standardbred mares. Equine Vet J, 53(3), 542-548. https://doi.org/10.1111/evj.13294

Publication

ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 53
Issue: 3
Pages: 542-548

Researcher Affiliations

Nostell, Katarina
  • Department of Clinical Sciences, Uppsala, Sweden.
Lindåse, Sanna
  • Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Winqvist, Ellen
  • Swedish Board of Agriculture, Jönköping, Sweden.
Bröjer, Johan
  • Department of Clinical Sciences, Uppsala, Sweden.

MeSH Terms

  • Animals
  • Blood Pressure
  • Diet / veterinary
  • Female
  • Horse Diseases / etiology
  • Horses
  • Hydrocortisone
  • Insulin
  • Obesity / etiology
  • Obesity / veterinary

Grant Funding

  • Swedish - Norwegian Foundation for Equine Research

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Citations

This article has been cited 2 times.
  1. D' Fonseca NMM, Beukers M, Wijnberg ID, Navas de Solis C, de Ruijter-Villani M, van Doorn DA, Stout TAE, Roelfsema E. Effect of a long-term high-energy diet on cardiovascular parameters in Shetland pony mares. J Vet Intern Med 2021 Sep;35(5):2427-2436.
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  2. López Pérez AB, Brown JL, Punyapornwithaya V, Thitaram C, Pongsumpan J, Supanta J, Tocharoennirattisai W, Khonmee J. Metabolic profiles of captive Asian elephants (Elephas maximus) in Lao PDR and Thailand. PLoS One 2025;20(12):e0334550.
    doi: 10.1371/journal.pone.0334550pubmed: 41406080google scholar: lookup