Volatile fatty acids and the role of the large intestine in the control of feed intake in ponies.

This study investigates the impact of volatile fatty acids (VFAs) and the large intestine’s role in managing feed intake in horses. It suggests that VFAs in the horse’s cecum, part of the large intestine, can influence meal size and frequency.

Study Design and Methodology

The research made use of ponies with cecal fistulas, which are abnormal connections between the cecum and the outside of the body. The ponies had free access to a pelleted diet. Researchers introduced treatments, in the form of different doses of VFA solutions, into the pony’s body 15 minutes before they were allowed to feed following a four-hour fast. They also had a control group where water was used instead of a VFA solution. Metrics such as the latency to eat, first meal size, duration, and first intermeal interval were recorded, giving a comprehensive view of each pony’s eating behavior.

• The treatments were given as single doses in a crossover design, allowing the same pony to receive more than one treatment, with each test separated by a period of time.
• The response to these treatments was tracked by monitoring the ponies’ feed intake at two different time intervals: three hours and 18 hours after the treatments.

Results and Findings

The outcomes showed that changes in the concentration of VFAs in the cecum can lead to alterations in the feeding behavior of ponies.

• Intracecal infusions of propionate, a type of VFA, at the rate of .4 mmol per kilogram of body weight increased total feed intake by 7.5% compared to the control group.
• Higher doses of propionate (.75 mmol/kg body weight) and acetate (1.0 and 1.25 mmol/kg body weight), another type of VFA, reduced feed intake by extending the first intermeal interval to 143% and 71-74% respectively. However, their total feed intake over 24 hours did not differ significantly from the control group.
• A high dose of propionate (1.0 mmol/kg body weight) reduced the size of the first meal by 22% without significantly affecting subsequent feeding behavior.

In conclusion, the study indicates that the composition of VFAs residing within the cecum might play a role in controlling meal size and frequency in ponies. This research provides a potential avenue for further investigation into dietary control and animal health.