Effects of a docosahexaenoic acid–rich microalgae nutritional product on insulin sensitivity after prolonged dexamethasone treatment in healthy mature horses

Kristen M. Brennan Center for Animal Nutrigenomics and Applied Animal Nutrition, Alltech Inc, 3031 Catnip Hill Rd, Nicholasville, KY 40356.

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Daniel E. Graugnard Center for Animal Nutrigenomics and Applied Animal Nutrition, Alltech Inc, 3031 Catnip Hill Rd, Nicholasville, KY 40356.

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Malinda L. Spry Center for Animal Nutrigenomics and Applied Animal Nutrition, Alltech Inc, 3031 Catnip Hill Rd, Nicholasville, KY 40356.

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Tammy Brewster-Barnes Department of Animal and Food Sciences, College of Agriculture, Food, and Environment, University of Kentucky, Lexington, KY 40546.

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Allison C. Smith Center for Animal Nutrigenomics and Applied Animal Nutrition, Alltech Inc, 3031 Catnip Hill Rd, Nicholasville, KY 40356.

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Rachel E. Schaeffer Center for Animal Nutrigenomics and Applied Animal Nutrition, Alltech Inc, 3031 Catnip Hill Rd, Nicholasville, KY 40356.

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Kristine L. Urschel Department of Animal and Food Sciences, College of Agriculture, Food, and Environment, University of Kentucky, Lexington, KY 40546.

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DOI:
https://doi.org/10.2460/ajvr.76.10.889
Volume/Issue:
Volume 76: Issue 10
Online Publication Date:
01 Oct 2015
Restricted access
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Abstract

OBJECTIVE To determine effects of a microalgae nutritional product on insulin sensitivity in horses.

ANIMALS 8 healthy mature horses.

PROCEDURES Horses (n = 4/group) received a basal diet without (control diet) or with docosahexaenoic acid–rich microalgae meal (150 g/d) for 49 days (day 0 = first day of diet). On day 28, an isoglycemic hyperinsulinemic clamp procedure was performed. Horses then received dexamethasone (0.04 mg/kg/d) for 21 days. On day 49, the clamp procedure was repeated. After a 60-day washout, horses received the alternate diet, and procedures were repeated. Plasma fatty acid, glucose, and insulin concentrations and glucose and insulin dynamics during the clamp procedure were measured on days 28 and 49. Two estimates of insulin sensitivity (reciprocal of the square root of the insulin concentration and the modified insulin-to-glucose ratio for ponies) were calculated.

RESULTS Baseline glucose and insulin concentrations or measures of insulin sensitivity on day 28 did not differ between horses when fed the control diet or the basal diet plus microalgae meal. On day 49 (ie, after dexamethasone administration), the microalgae meal was associated with lower baseline insulin and glucose concentrations and an improved modified insulin-to-glucose ratio for ponies, compared with results for the control diet.

CONCLUSIONS AND CLINICAL RELEVANCE Although the microalgae meal had no effect on clamp variables following dexamethasone treatment, it was associated with improved plasma glucose and insulin concentrations and insulin sensitivity estimates. A role for microalgae in the nutritional management of insulin-resistant horses warrants investigation.

Abstract

OBJECTIVE To determine effects of a microalgae nutritional product on insulin sensitivity in horses.

ANIMALS 8 healthy mature horses.

PROCEDURES Horses (n = 4/group) received a basal diet without (control diet) or with docosahexaenoic acid–rich microalgae meal (150 g/d) for 49 days (day 0 = first day of diet). On day 28, an isoglycemic hyperinsulinemic clamp procedure was performed. Horses then received dexamethasone (0.04 mg/kg/d) for 21 days. On day 49, the clamp procedure was repeated. After a 60-day washout, horses received the alternate diet, and procedures were repeated. Plasma fatty acid, glucose, and insulin concentrations and glucose and insulin dynamics during the clamp procedure were measured on days 28 and 49. Two estimates of insulin sensitivity (reciprocal of the square root of the insulin concentration and the modified insulin-to-glucose ratio for ponies) were calculated.

RESULTS Baseline glucose and insulin concentrations or measures of insulin sensitivity on day 28 did not differ between horses when fed the control diet or the basal diet plus microalgae meal. On day 49 (ie, after dexamethasone administration), the microalgae meal was associated with lower baseline insulin and glucose concentrations and an improved modified insulin-to-glucose ratio for ponies, compared with results for the control diet.

CONCLUSIONS AND CLINICAL RELEVANCE Although the microalgae meal had no effect on clamp variables following dexamethasone treatment, it was associated with improved plasma glucose and insulin concentrations and insulin sensitivity estimates. A role for microalgae in the nutritional management of insulin-resistant horses warrants investigation.

Contributor Notes

Address correspondence to Dr. Brennan (Kbrennan@alltech.com).
Cover American Journal of Veterinary Research
American Journal of Veterinary Research
Publication Date:
01 Oct 2015

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