Premium
The effect of diet‐induced obesity and pasture on blood pressure and serum cortisol in Standardbred mares
Author(s) -
Nostell Katarina,
Lindåse Sanna,
Winqvist Ellen,
Bröjer Johan
Publication year - 2021
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.13294
Subject(s) - pasture , medicine , weight gain , endocrinology , blood pressure , zoology , horse , insulin resistance , insulin , obesity , body weight , biology , agronomy , paleontology
Background Obesity is associated with insulin resistance, vascular dysfunction and altered cortisol metabolism both in humans and in horses. Objectives 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. Study design 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 CLAMP ) 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 < 0.05 were considered as statistically different. Results All horses became obese during the weight gain period (BCS> 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 CLAMP was unaffected by weight gain 0.9 ± 0.1 vs 1.0 ± 0.1 ([mg/kg/min × 10 3 ]/[µIU/mL × mmol/L])) but improved after pasture (1.6 ± 0.1 ([mg/kg/min × 10 3 ]/ [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. Main limitations 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.