Effects of feeding state on glycaemic and insulinaemic responses to a starchy meal in horses: a methodological approach.

The research study investigated the impact of feeding status on the glycaemic and insulinaemic responses of horses to a starchy diet, showing that 12-hour feed restriction prior to consuming corn, and not eating hay after, offers the best-defined conditions for the horses’ glucose and insulin levels.

Research Methodology and Design

• The researchers employed a methodological approach to classify starchy diets for horses based on feeding status, particularly focusing on glycaemic and insulinaemic responses of the animals.
• The experiment involved four horses undergoing different feeding protocols, with the diet primarily comprising of hay and cracked corn (CC). The order of this process was randomized for each horse.
• The four different feeding protocols were; 12 hours of unlimited hay before feeding CC and 9 hours of unlimited hay after CC intake (+CC+), 12 hours of unlimited hay before feeding CC and no hay after CC intake (+CC-), 12 hours feed restriction before feeding CC and 9 hours of unlimited hay after CC intake (-CC+), and 1.2 kg hay/100 kg body weight per day, split into two portions offered at 9am and 7pm, with 12 hours feed restriction before feeding CC and no hay after CC intake (-CC-).
• The amount of CC given to the horses was adjusted according to the horse’s body weight (BW), with a starch intake of 2 g/kg BW.

Findings and Observations

• The results revealed that the different hay offerings did not significantly affect the basal plasma glucose and insulin levels in the horses.
• There was a noticeable increase in the plasma glucose and insulin levels after the horses consumed CC, regardless of the diet protocol.
• The highest peak of glucose levels was found in the -CC+ diet protocol, while the lowest glucose peaks were associated with the +CC- diet.
• Similarly, the +CC- diet resulted in lower insulin peaks and the -CC+ diet observed the highest insulin peaks.
• Insulin levels in horses following the -CC- and +CC- diet protocols returned to resting values about 300 minutes after CC feeding. However, for the +CC+ and -CC+ diets, insulin levels remained above resting levels even 510 minutes after CC intake.

Conclusion

• The study concludes that the optimal feeding status for horses to ideally react to a starchy diet is to restrict feed for 12 hours before feeding them with the starchy diet and ensuring no further roughage intake during the blood-sampling period.