Effects of processing barley on its digestion by horses

Area of Science:

• Equine nutrition
• Digestive physiology

Background:

• Starch digestibility varies with barley processing.
• Understanding equine starch digestion is crucial for diet formulation.

Purpose of the Study:

• To evaluate the impact of rolled, micronized, and extruded barley on equine starch digestion.
• To assess pre-cecal starch digestibility and hindgut fermentation in horses fed different barley preparations.

Main Methods:

• Four horses were fed diets with rolled, micronized, or extruded barley (2 g starch/kg bodyweight).
• Blood samples measured glycemic and insulinemic responses.
• Breath samples analyzed for hydrogen and methane to assess fermentation.

Main Results:

• Extruded barley elicited the highest peak glucose and insulin levels, suggesting lower pre-cecal starch digestibility.
• Micronized barley resulted in intermediate responses.
• Rolled barley showed the lowest glycemic and insulinemic responses.
• Postprandial breath hydrogen and methane levels varied, with no significant differences between treatments, but a trend towards higher methane with rolled barley.

Conclusions:

• Barley processing significantly influences starch digestion and absorption in horses.
• Extrusion appears to reduce pre-cecal starch digestibility the most among the tested methods.
• Further research is needed to fully elucidate the implications of these findings on hindgut fermentation and overall equine health.