Effects of a supplement containing chromium and magnesium on morphometric measurements, resting glucose, insulin concentrations and insulin sensitivity in laminitic obese horses

Authors

  • K. A. CHAMEROY,

    1. Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville; and Department of Clinical Studies (Boston), University of Pennsylvania, Kennett Square, USA.
    Search for more papers by this author
  • N. FRANK,

    Corresponding author
      email: nfrank@utk.edu
    Search for more papers by this author
  • S. B. ELLIOTT,

    1. Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville; and Department of Clinical Studies (Boston), University of Pennsylvania, Kennett Square, USA.
    Search for more papers by this author
  • R. C. BOSTON

    1. Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville; and Department of Clinical Studies (Boston), University of Pennsylvania, Kennett Square, USA.
    Search for more papers by this author

  • Presented in part at American College of Veterinary Internal Medicine 2009, Montreal, Canada.

email: nfrank@utk.edu

Summary

Reasons for performing study: Obesity and insulin resistance are risk factors for laminitis in equids and supplements containing chromium and magnesium might improve insulin sensitivity.

Hypothesis: A supplement containing chromium, magnesium and other nutraceuticals would alter morphometric measurements, blood variables, and insulin sensitivity in laminitic obese horses.

Methods: Twelve previously laminitic obese (body condition score ≥ 7/9) horses were randomly allocated to treatment (n = 6) and control (n = 6) groups and 2 obese horses with clinical laminitis were included in the treatment group. Treated animals received 56 g supplement with 0.25 kg oats once daily for 16 weeks. The supplement contained chromium (5 mg/day as yeast), magnesium (8.8 g/day as oxide/proteinate), and other nutraceuticals. Insulin-modified frequently sampled i.v. glucose tolerance tests were performed with hay provided at 0, 8 and 16 weeks, and insulin sensitivity was estimated by minimal model analysis. Physical measurements were collected at the same points. Horses were not exercised.

Results: Hyperinsulinaemia (>30 µu/ml) was detected in 12 of 14 horses prior to treatment. Glucose and insulin data from one mare with clinical laminitis were excluded because of persistent pain. Mean ± s.d. insulin sensitivity was 0.64 ± 0.62 × 10−4 l/min/mu prior to treatment for the remaining 13 horses. Time and treatment × time effects were not significant for any of the variables examined, with the exception of resting insulin concentrations, which significantly increased over time (P = 0.018). Health status remained the same.

Conclusions: The supplement containing chromium and magnesium evaluated in this study did not alter morphometric measurements, blood variables, resting insulin concentrations or insulin sensitivity in laminitic obese horses.

Potential relevance: Additional research is required to determine the appropriate use of chromium and magnesium supplements in horses.

Ancillary