The effects of feeding frequency on glycemia and insulinemia in moderately exercised young horses.

Objective Overview

• This study examined how feeding young horses either two larger meals or multiple smaller meals throughout the day influences their blood sugar and insulin levels following exercise.
• The research aimed to determine whether spreading grain intake across many feedings can reduce spikes in insulin that may contribute to metabolic problems such as insulin dysregulation.

Background

• Horses often receive concentrates (grain-based feed) twice daily along with forage to meet their energy needs.
• Large, infrequent high-grain meals can cause digestive and metabolic issues, including undesirable insulin responses.
• Insulin dysregulation in horses is linked to serious conditions like laminitis, making management of blood insulin levels important.
• Moderately exercised young horses are used in this study to reflect typical management and energy requirements.

Study Design and Methods

• Thirty-two healthy Quarter Horses aged 2-3 years were randomly assigned to two groups:
• Traditional Feeding (TF): Two grain meals per day.
• Fractioned Feeding (FF): Grain automatically delivered every hour over 10 hours, dividing the daily grain ration into multiple smaller meals.
• Grain comprised 40% of their daily dry matter intake, and forage made up the remaining 60%.
• Oral Sugar Tests (OST), a diagnostic approach to assess insulin sensitivity, were performed at baseline (before feeding changes), and after 30 and 60 days on the feeding regimen.
• On day 45, a subgroup of 10 horses underwent an 8-hour postprandial (after eating) glucose and insulin monitoring test to observe blood sugar and insulin changes throughout the day.
• Plasma basal cortisol (stress hormone) was also measured at 0, 30, and 60 days to rule out stress-related effects.

Key Findings

• The Oral Sugar Test results showed an increase in insulin levels 75 minutes after sugar intake on day 30 in both feeding groups, indicating some rise in insulin due to feeding changes, but no differential effect between groups at this point.
• During the extensive 8-hour postprandial testing:
• Horses on the Traditional Feeding (TF) regimen had significantly higher glucose and insulin peak levels compared to those on the Fractioned Feeding (FF) regimen.
• Insulin area under the curve (AUC) at 60 and 180 minutes was greater in TF horses, signaling a larger insulin response and greater post-meal insulin exposure.
• The total insulin AUC (over the full period) was also significantly lower in the FF group (approximately 1119 μIU·min/mL) compared to the TF group (approximately 1406 μIU·min/mL), showing a reduction in overall insulin burden with fractioned feeding.
• Basal cortisol measurements did not indicate stress differences affecting results.

Interpretation and Implications

• Feeding horses smaller, more frequent grain meals reduces the load of non-structural carbohydrates (NSC) per meal, which in turn dampens the insulin spikes after feeding.
• This approach can potentially help manage insulin dysregulation or hyperinsulinemia, which are risk factors for laminitis, a painful and often debilitating hoof condition.
• Fractioned feeding may thus represent an effective nutritional strategy for young horses, especially those at risk of metabolic disorders, by promoting healthier postprandial insulin responses.
• Such feeding strategies could be incorporated into equine management practices aiming to mitigate metabolic challenges without sacrificing energy intake required for moderate exercise and growth.

Conclusions

• Feeding frequency significantly influences insulin and glucose dynamics in young, moderately exercised horses.
• Delivering grain in many smaller meals throughout the day reduces the magnitude of insulin responses compared to traditional twice-daily feeding.
• This management approach warrants further direct testing and could be a valuable tool for preventing or managing insulin-related metabolic disorders in horses.