Mobile bag starch prececal disappearance and postprandial glycemic response of four forms of barley in horses.

This research article studies the prececal starch digestibility in horses and estimates glucose uptake from four forms of barley – whole grain, ground, steam flaked, and pelleted. Results reveal that whole barley showed the least prececal starch digestibility, with no significant variation in glycemic parameters.

Research Design

• The experiment includes four mature geldings which are cecally fistulated and were fed with a 62:38 meadow hay: concentrate diet.
• The diet was administered at a rate of 1.7 kg Dry Matter (DM) per 100 kg body weight and was part of a 4×4 Latin square design experiment – a statistical method often employed in agriculture to reduce the difference in soil variability.
• The starch supply in the morning meal totaled 2.7 grams of starch/kg body weight. The barley supply was introduced in different forms – whole grain, ground (2.5 mm), steam flaked, and pelleted – making up 80% DM of the concentrate.
• On the day of the measurements, no hay was given in the morning meal.

Methodology

• To determine the digestibility, mobile bag DM and starch disappearance was observed and measured.
• Apart from ground barley, each barley form was grounded to 4mm before being introduced into the bag.
• These nylon bags were intubated in the horse receiving the pelleted barley and collected from the cecum (a part of the digestive tract) after 10 hours.
• Blood samples were also collected via an indwelling jugular catheter before the morning meal to measure the postprandial (after meal) glycemia, and the glucose in the blood was analysed with a portable glucose meter.

Findings

• The findings showed that the digestibility of the starch was dependent on the form of barley. The whole barley exhibited the lowest prececal mobile bag starch disappearance, giving headway to further research.
• There was no significant difference detected among the three processed grains.
• On correlating glycemic parameters – which measure the effect of food on a person’s blood sugar – to the amount of prececal mobile bag disappeared starch calculated as the starch intake in the morning meal, it was noted that no significant effect of the barley form was found.

Conclusion

• These results suggest that further studies need to be conducted to improve the methods of estimating prececal starch digestion of processed cereals in different digestive segments of horses, as the results exhibit large individual variations.
• With whole barley exhibiting the lowest digestibility, changes in processing technique could potentially enhance digestibility of starch in equine diets.