Effect of increased adiposity on insulin sensitivity and adipokine concentrations in different equine breeds adapted to cereal-rich or fat-rich meals.

This research examined how diet and obesity affect insulin levels and fat-related hormones in different types of horses, such as Standardbreds, mixed-breed ponies, and Andalusian. The study fed the horses high-carbohydrate or high-fat diets for 20 weeks to induce obesity and monitored the changes in their insulin sensitivity and fat-related hormone concentrations. It found that the high-carbohydrate diet notably impacted the horses’ insulin sensitivity and hormone levels, whereas the high-fat diet did not.

Research methodology and diet plan

• The research involved an equal number of Standardbreds, mixed-breed ponies, and Andalusian horses.
• The horses were fed unlimited hay and either a diet rich in cereals (CHO), fat (FAT), or a control diet (CON).
• The high-calorie CHO and FAT diets were used to deliberately induce obesity over the course of 20 weeks. The diets were increased gradually until the horses were consuming 200% of their daily energy requirements by the end of the study.
• The control group, on the other hand, was given only a basal ration and its body condition was kept moderate.

Findings and observations

• After the 20 weeks, significant increases were observed in the bodyweight, body condition score, total body fat mass, and plasma leptin concentrations (a hormone that helps regulate energy balance) in both the CHO and FAT groups in comparison to the CON group.
• The CHO group, however, displayed lower insulin sensitivity (the measure of how responsive cells are to insulin) and a higher acute insulin response than the CON group, whereas the FAT group did not exemplify such variations.
• Breed-wise, the ponies and Andalusians showed lower insulin sensitivity, irrespective of their diet, compared to the Standardbreds.
• The adiponectin levels (a hormone involved in glucose regulation and fatty acid breakdown) were not different between the FAT and CON groups but were significantly reduced in the CHO group.

Conclusions

• The results from this study suggest that diets high in cereals play a more significant role in affecting insulin sensitivity in horses than mere obesity.
• However, it’s unclear whether the lower adiponectin concentrations observed in the CHO group are a cause or a result of the insulin dysregulation, thus requiring further research in the field.