Meal-induced gastric relaxation and emptying in horses after ingestion of high-fat versus high-carbohydrate diets.

The research article investigates how high-carbohydrate and high-fat meals affect the relaxation and emptying of a horse’s stomach. The study discovered that high-carbohydrate meals induced longer relaxation in the stomach’s proximal portion, while meals containing high-fat did not significantly influence gastric motility.

Methods and Experimental Design

• The study involved two phases and used six healthy adult horses. They evaluated the effects of ingesting a high-carbohydrate meal against those of a high-fat meal on the relaxation of the horse’s proximal stomach portion and the subsequent gastric emptying.
• In the first phase, horses received either a high-fat (8% fat) or a high-carbohydrate (3% fat) pelleted meal. These meals had the same volume, caloric density, and protein content.
• In the second phase, the meals consisted of either a commercial sweet feed meal or this meal supplemented with 12.3% fat corn oil or an equal caloric amount of 2.9% fat glucose.
• To measure proximal gastric tone, variations in the volume of an intragastric bag introduced into the horse’s stomach via a cannula were evaluated. This bag maintained a constant internal pressure by an electronic barostat.
• The 13C-octanoic acid breath test was used to measure the rate of gastric emptying simultaneously.
• The researchers conducted additional experiments to study the interaction between the two techniques.

Key Findings

• Meals with higher carbohydrate content resulted in a noticeably longer receptive relaxation of the horse’s stomach’s proximal section than those with higher fat content.
• However, the accommodation response, which refers to the stomach’s ability to relax and accommodate food without increasing pressure, was found to be similar for both the high-fat and high-carbohydrate meals.
• The use of the breath test marker to label meals influenced the accommodation response as measured by the barostat.
• The rates of gastric emptying were not significantly different between high-fat and high-carbohydrate meals. Nevertheless, high-carbohydrate meals initially emptied more slowly.

Conclusions

• The researchers concluded that unlike in most species, diet supplementation with fat may not have a profound effect on gastric motility in horses.
• High-carbohydrate meals resulted in a more prolonged relaxation of the proximal portion of the stomach compared to high-fat meals.