Effect of micronization and meal size of corn grain on glycemic response and in vitro hindgut acidosis potential in horses.

The researchers of this study aimed to determine the impact of corn grain micronization and starch levels on the blood sugar levels in horses, and to assess the effect of micronization on the risk of hindgut acidosis. They found that micronized corn grain increased the glucose concentrations in the horse’s blood and increased the rate of digestive fermentation, but the scale of these increases was not as pronounced as was expected based on previous in-vitro studies.

Study Design and Methodology

• The study was carried out using six healthy, non-pregnant mares aged 6 to 10 years.
• The experiment followed a 2×3 factorial cross-over design, meaning each mare was subjected to each treatment in different periods.
• The treatment consisted of two different forms of corn grain (ground and micronized flaked) and three different levels of starch (1, 1.5, and 2 g/kg of body weight per meal).
• Blood samples were taken at numerous time intervals starting from before feeding, until 300 minutes after feeding. These samples were analyzed to determine the glucose levels in the plasma.

Results

• Micronized flaked corn resulted in three times more digestion in the small intestine compared to ground corn based on in vitro enzymatic dry matter disappearance.
• The digestion residues of micronized flaked corn fermented liked a bullet, almost 38.59% faster during in vitro hindgut incubation compared to the ground corn residues.
• Feeding horses micronized flakes of corn resulted in higher post-meal plasma glucose concentrations compared to feeding them ground corn.
• Increasing the starch levels in each meal from 1 to 2 g/kg of body weight resulted in higher plasma glucose concentrations.
• No significant interaction was found between the form of corn grain and the starch level per meal. Meaning, the increase in plasma glucose levels cannot be attributed to a specific form-starch level combination.

Conclusion

• The results show that processing corn grain by micronization or increasing the starch level per meal, increase the plasma glucose concentrations in horses.
• However, these increases were not as pronounced as were anticipated from previous in vitro studies.