Plasma glucose and insulin responses of Thoroughbred mares fed a meal high in starch and sugar or fat and fiber.

The research investigates how different types of horse feed influence the levels of blood glucose and insulin in pregnant and lactating Thoroughbred mares. The results suggest that feeding horses with a diet rich in fat and fiber moderates fluctuations in glucose and insulin levels compared to a diet high in sugar and starch.

Research Methodology

• The research took place on twelve Thoroughbred mares and compared their blood glucose and insulin levels after consuming three different types of feeds: a pelleted concentrate (PC), a traditional sweet feed high in sugar and starch (SS), and a feed high in fat and fiber (FF). The feeds had similar Digestible Energy (DE) and Crude Protein (CP) but varied in their composition of fat, Neutral Detergent Fiber (NDF), and nonstructural carbohydrates.
• Mares were randomly divided into two groups based on their weight and foaling date. All mares were fed PC during late pregnancy and, after foaling, one group was fed the SS and the other the FF feed for trials in early and late lactation.
• The mares were kept in stalls and starved overnight, and a series of blood samples were collected from them for nearly 7 hours after consuming the meal. These samples were analyzed for glucose and insulin concentrations.

Key Findings

• The baseline values for glucose and insulin for all diets and stages were computed. The research found that the glucose and insulin responses to the PC diet did not differ between the two groups, suggesting metabolic similarities between the groups.
• The research found that peak plasma glucose and insulin concentrations were significantly higher in the group that was fed the SS diet compared to the group that was fed the FF diet during both the early and late periods of lactation.
• Similarly, the overall glucose and insulin levels (AUC) were significantly higher in the SS diet group than the FF diet group.

Conclusion

• The research concluded that the fluctuations in metabolism can be mitigated by replacing a diet rich in sugar and starch with one rich in fat and fiber. This change in diet might lower the risk of specific digestive and metabolic disorders linked to feed the pregnant or lactating mares grain-based concentrates.