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

The research explores the impact of a docosahexaenoic acid-rich microalgae nutritional supplement on insulin sensitivity in horses, which may suggest its potential for managing insulin resistance in horses.

Research Methods

• The researchers chose eight healthy, mature horses for the study.
• These horses were divided into two groups, each containing four horses. One group was given a base diet (control) and the other a base diet supplemented with a docosahexaenoic acid-rich microalgae meal.
• This diet plan was maintained for 49 days, with Day 0 marking the start of the new diet regimen.
• On the 28th day, an isoglycemic hyperinsulinemic clamp procedure – a medical procedure used to assess insulin sensitivity – was performed.
• Following this, all horses were given dexamethasone for 21 days, a medication used to decrease inflammation and suppress the immune system.
• On Day 49, the clamp procedure was performed again to analyze changes in insulin sensitivity. This was followed by a 60-day washout period, post which, the dietary plan was reversed, and the procedures were repeated.

Measurements and Analysis

• On Days 28 and 49, measurements were taken of plasma fatty acid, glucose, and insulin concentrations. Additionally, glucose and insulin dynamics during the clamp procedure were also observed.
• Two unique methods were used to estimate insulin sensitivity: a method based on the reciprocal of the square root of the insulin concentration and a second one commonly used for ponies that uses a modified insulin-to-glucose ratio.

Results of the Study

• The study found that there was no significant difference in glucose and insulin concentrations or insulin sensitivity on Day 28, no matter the diet fed to the horses.
• However, on Day 49, after the administration of dexamethasone, the horses fed the microalgae meal showed lower baseline insulin and glucose concentrations, and a better modified insulin-to-glucose ratio compared to those on a control diet.
• These results suggest the microalgae meal could have a positive effect on plasma glucose and insulin concentrations and insulin sensitivity estimates.

Conclusion and Further Research

• Although no direct effects were observed on clamp variables after the dexamethasone treatment, the study infers that the docosahexaenoic acid-rich microalgae meal could be associated with improved glucose levels and insulin sensitivity.
• The paper concludes by emphasizing the need for further investigation into the potential role of microalgae in the nutritional management of insulin-resistant horses.