Oral and intravenous carbohydrate challenges decrease active ghrelin concentrations and alter hormones related to control of energy metabolism in horses.

This research investigates the effect of grain and dextrose challenges on the plasma concentrations of various hormones related to energy metabolism in Standardbred mares. Findings indicate these challenges can significantly impact levels of glucose, insulin, ghrelin, leptin, and cortisol, potentially affecting energy regulation in these horses.

Objective and Methodology

• The study aimed to explore how grain and intravenous dextrose challenges alter plasma concentrations of certain hormones in Standardbred mares. These hormones include active ghrelin, leptin, adiponectin, glucose, insulin, and cortisol, which are essential for the control of energy metabolism.
• The experimental procedure involved delivering 0.5g of glucose per kilogram of Body Weight (BW) to the mares, either by intravenous dextrose (50% solution) or oral grain administration.

Findings: Oral Grain Challenge

• In response to the oral grain challenge, plasma glucose and insulin levels noticeably increased.
• The concentration of plasma ghrelin initially decreased significantly, but later it experienced a substantial rise.
• A reduction was observed in the concentration of plasma leptin.
• There was no change in plasma adiponectin concentration after the grain challenge.
• Notably, plasma cortisol concentrations reduced substantially.

Findings: Intravenous Dextrose Challenge

• In reaction to the intravenous dextrose challenge, plasma glucose and insulin concentrations dramatically increased.
• Similar to the grain challenge, plasma active ghrelin concentration first decreased significantly before rising sharply.
• Plasma leptin concentration showed an increase.
• There was no change in plasma adiponectin concentration during the dextrose challenge.
• The cortisol concentration in the plasma increased slightly.

Conclusion

• The research concludes that both grain and intravenous nutrient challenges have the potential to significantly alter variables associated with energy metabolism in Standardbred mares.
• The observed acute changes in glucose and insulin may thus be modulating changes in ghrelin and leptin, further influencing the horses’ energy metabolism.