Ultrasonographic measurements of localized fat accumulation in Shetland pony mares fed a normal v. a high energy diet for 2 years.

This study is about investigating whether feeding Shetland pony mares a long-term high energy diet rather than their standard maintenance diet would lead to significant changes in the animals’ body weight, local fat accumulation and localization.

Research Purpose and Methodology

The goal of the research was to evaluate the health risks associated with obesity, hypothesizing how the localization or distribution of fat in the body might affect health. The researchers were interested in whether fat accumulation in certain parts of the body would be more harmful health-wise than an overall increase in body weight.

• The researchers conducted a randomized controlled clinical trial, using eight mares aged between 3 to 7 years as subjects. The ponies were divided into two groups: a control group, which was fed their normal diet, and a high energy (HE) group, which ate double the usual dietary energy requirements for two consecutive summers.
• Monthly measurements were conducted using ultrasonography to assess fat accumulation in five key locations on the ponies’ bodies. These locations included, the retroperitoneal, axillary, withers, intercostal, and rump areas.

Findings and Conclusions

The results of the study showed that ponies in the HE group had significantly more fat accumulation than those in the control group.

• Body condition scores (BCS) and body weight (BW) were also significantly higher in the HE group. This group’s mean BW increased by 52% (265±13.94kg) and its BCS increased by 70% to 9.0±0.4. There were no significant changes in the control group’s BW or BCS.
• Fat depth in all measured locations in the HE group increased, with the most significant increase observed in the retroperitoneal region, which indicates a higher accumulation of intra-abdominal fat.
• The researchers concluded that the horses’ body did have a limit as to how much subcutaneous fat it could store, as they recorded an initial increase in fat thickness followed by a plateau.

Overall, fat storage and subsequent obesity in Shetland ponies were significantly influenced by diet. The long-term high-energy diet led to excessive fat accumulation and weight gain. This might suggest similar results previously seen in human studies that there is a limit to the expandability of adipose tissue in mammals.