This study was conducted to evaluate the effects of different oat processing techniques on the plasma
glucose and
insulin response in horses. In a cross-over design, six horses (ages 4-15 years, mean
body weight+/-SD: 450+/-37 kg) were fed in random order: untreated oats, finely ground,
steam-flaked and popped oats. The total oat intake varied between 1.05-1.5 kg/day, and the amount of diet was adjusted to a
starch content of 630 g
starch per day and horse (1.2-1.5 g
starch/kg BW/day). During the stabilization period of 10 days, horses additionally received 6 kg grass hay. Following this adaptation period, plasma
glucose and
insulin responses to the respective dietary treatments were tested. Horses were fed their test diet (exclusively oats), and blood samples were collected at defined times to determine glycaemic and
insulin response. Oat feeding resulted in a significant increase in mean plasma
glucose and
insulin concentration. However,
glucose and
insulin peaks as well as their respective areas under the curves were not clearly influenced by oat processing. The glycaemic index varied between 94.7+/-11.2% (
steam-flaked oats) and 102.6+/-14.5% (finely ground oats, n.s.), the
insulin index ranged between 93.8+/-18.9% (popped oats) and 150.0+/-77.6% (finely ground oats, n.s.). The
insulin reaction to oat feeding showed a high variability between the horses. The results of this study indicate that the
glucose and
insulin responses are not clearly altered by the different types of oat processing. However, the
glucose and
insulin responses tended to be lower in thermally treated oats when compared with untreated or finely ground oats.