Voluntary feed intake and leptin sensitivity in ad libitum fed obese ponies following a period of restricted feeding: a pilot study.
Authors: Van Weyenberg S, Buyse J, Kalmar I D, Swennen Q, Janssens G P J
Journal: Journal of animal physiology and animal nutrition
Summary
# Editorial Summary When obese ponies transition from restricted to ad libitum feeding, their feed intake and plasma leptin concentrations follow predictable patterns over approximately two weeks, yet individual responses reveal important differences in how their bodies regulate appetite. This pilot study monitored eight obese Shetland ponies during a 14-day period of ad libitum roughage access, measuring daily intake and plasma leptin concentration to investigate whether leptin—the satiety hormone—functions normally in equine obesity. Feed intake initially spiked on day one, dropped sharply on day two as leptin rose, then stabilised by day eight; however, ponies with higher baseline leptin showed a blunted appetite-suppressing effect, indicating variable leptin sensitivity across the group despite similar body condition scores. These findings suggest that obese ponies may develop leptin resistance (diminished cellular response to the hormone) as a compensatory mechanism, driving higher leptin production in an attempt to control feed intake—a pattern documented in other species but previously unclear in equines. For practitioners, this work implies that obesity management strategies may need individualising based on metabolic responsiveness rather than assuming uniform feeding protocols will be equally effective, and highlights the potential importance of addressing leptin sensitivity during weight loss programmes rather than restricting calories alone.
Read the full abstract on PubMed
Practical Takeaways
- •Obese ponies transitioning to ad libitum feeding show variable appetite responses in the first 2 days; monitor individual responses as leptin sensitivity differs between animals
- •Plasma leptin concentration alone is not a reliable indicator of obesity or appetite regulation in obese ponies—leptin sensitivity appears more important than absolute leptin levels
- •Feed management strategies for obese ponies should account for individual differences in leptin sensitivity, not just body condition score
Key Findings
- •Feed intake increased on day 1 of ad libitum feeding, decreased on day 2, then stabilized by day 8 in obese Shetland ponies
- •Plasma leptin concentration increased during the first 2 days then remained constant, despite continued feed intake changes
- •Ponies with higher initial leptin concentration showed lower anorectic response to leptin, indicating variable leptin sensitivity among obese individuals
- •Large variations in plasma leptin among obese ponies with similar body condition scores may reflect compensatory leptin overproduction in response to reduced leptin sensitivity