Determination of sweetener specificity of horse gut-expressed sweet taste receptor T1R2-T1R3 and its significance for energy provision and hydration.

The researchers found that in horses, certain sweeteners stimulate a particular receptor in the gut which in turn enhances glucose absorption and hydration. This is especially significant for energy provision during demanding periods such as strenuous exercise, pregnancy, and lactation. The sweeteners sucralose, stevia, and NHDC are observed to activate this receptor, whereas cyclamate does not.

Objective of the Research

• The objective of the research was to determine the extent to which different sweeteners affect the T1R2-T1R3 taste receptors in horse intestines, which have been observed to signal for increase in absorption of glucose, sodium chloride, and water when stimulated.
• The study’s focus on horses arises from their expression of T1R2, T1R3, and related signaling elements in their intestinal tissue, which, when triggered, could enhance the animal’s energy provision and hydration, particularly crucial during strenuous activities, pregnancy, and lactation.

Amino Acid Substitutions and Pseudogenization

• The capability of various species to detect sweeteners widely differs due to amino acid substitutions and pseudogenization of taste receptor genes.
• Such genetic variances underline the importance of understanding each species’ specific reactions to different sweeteners, as applied in this study to horses.

Findings and Results

• Through an experimental process called heterologous expression, the research identified that the sweeteners sucralose, stevia, and neohesperidin dihydrochalcone (NHDC) are capable of activating horse T1R2-T1R3 receptors. In contrast, the sweetener cyclamate was unable to do this.
• Identifying these successful agent stimulants is a critical step in developing suitable dietary additives to enhance glucose absorption and hydration in horses and minimizing risks of intestinal disease caused by microbial fermentation of unabsorbed carbohydrates in the large intestine.