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

摘要

P>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 mu u/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 x 10-4 l/min/mu prior to treatment for the remaining 13 horses. Time and treatment x 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.