Correlation between plasma alpha-melanocyte-stimulating hormone concentration and body mass index in healthy horses.

The research attempts to identify a correlation between plasma alpha-melanocyte-stimulating hormone (alpha-MSH) levels and body mass index (BMI) in healthy horses. The study suggests the existence of a correlation, particularly in horses that are 10 years or older, though the exact cause of this link demands additional investigation.

Study Participants and Procedures

• The study included 82 healthy horses, and the various parameters such as plasma alpha-MSH concentration, weight, girth circumference, body length, body condition scores (BCS), and height in horses were recorded.
• The weight was estimated using a specific formula involving girth and length measurements and was used to calculate the BMI.
• The determination of the alpha-MSH hormone concentration in the blood samples was facilitated by radioimmunoassay, a technique that uses antibodies to measure concentrations of specific substances, in this case, the alpha-MSH hormone.

Results

• The study found a substantial correlation between BMI and BCS (rs = 0.60). This indicates that as the BCS (a visual assessment of a horse’s fat distribution) increases, the BMI also tends to increase.
• A weak correlation (rs = 0.25) was also observed between the concentration of alpha-MSH in the plasma and the BMI, suggesting a possible relationship between hormone levels and body condition in horses.
• Interestingly, this correlation is more pronounced in horses aged 10 years and older (rs = 0.49), but non-existent in those under 10 years old.
• Horses with a higher BMI were found to have significantly greater plasma alpha-MSH concentrations. The plasma alpha-MSH concentration range in horses belonging to the upper quartile of BMI was 2.0 to 95.3 pmol/L, while it was 3.6 to 15.7 pmol/L in the lowest quartile of BMI.

Analysis and Conclusion

• The findings suggest that there does exist a correlation between the plasma alpha-MSH concentration and the BMI in horses, reinforcing the hormonal factors possibly influencing body conditions in animals.
• The association is interestingly more evident in horses aged 10 years or older. However, further research is required to understand the cause of this correlation – whether it is due to defects in the melanocortin receptor or simply because the hormone concentration is a reflection of the amount of fat in the body.