Glycaemic and insulinaemic responses to mechanical or thermal processed barley in horses.
Authors: Vervuert I, Bothe C, Coenen M
Journal: Journal of animal physiology and animal nutrition
Summary
# Editorial Summary: Barley Processing and Metabolic Responses in Horses Vervuert and colleagues investigated whether mechanical or thermal processing of barley alters the postprandial glucose and insulin responses in equines, hypothesising that changes in pre-caecal starch digestibility would translate to measurable metabolic differences. Six horses received five different barley preparations—whole, finely ground, steamed, steam-flaked and popped—each delivering 630 g starch daily, with blood sampling at defined intervals to measure glucose and insulin concentrations. Steam-flaked barley produced the highest absolute glucose (6.52 mmol/l) and insulin peaks despite moderate starch gelatinisation (28.7%), whilst popped barley showed less pronounced responses despite nearly complete gelatinisation (95.6%); interestingly, the degree of starch gelatinisation did not correlate directly with metabolic response intensity. For practitioners managing horses prone to hyperinsulinaemia or equine metabolic syndrome, these findings suggest that processing method influences glycaemic load more than simple starch availability measures would predict, and that steam-flaking—a common commercial process—may merit reconsideration where metabolic stability is a priority.
Read the full abstract on PubMed
Practical Takeaways
- •Processing method matters for managing blood glucose and insulin spikes in horses — steam-flaking and popping barley produce larger metabolic responses than whole or ground barley, which may be important for horses prone to laminitis or metabolic disorders
- •Starch gelatinization percentage alone cannot predict metabolic response; consider the specific processing method when selecting barley for metabolically sensitive horses
- •If feeding barley to horses with insulin resistance or laminitis risk, whole or finely ground barley appears safer than thermally processed varieties based on these glycaemic and insulinaemic data
Key Findings
- •All barley processing methods significantly increased plasma glucose and insulin within 30-45 minutes of feeding
- •Steam-flaked barley (DG 28.7%) produced the highest glucose peak (6.52 ± 0.64 mmol/l) despite intermediate starch gelatinization
- •Popped barley (DG 95.6%) showed more pronounced glycaemic and insulinaemic responses than expected, contrary to the pattern observed with steam-flaked barley
- •No consistent linear association existed between the degree of starch gelatinization and the magnitude of post-prandial glucose and insulin responses