Effects of l-carnitine supplementation on body weight losses and metabolic profile in obese and insulin-resistant ponies during a 14-week body weight reduction programme

There is growing awareness of obesity and insulin resistance in ponies; therefore nutritional management strategies need to be developed. The present study was conducted to investigate the effects of l-carnitine supplementation on body weight (BW) losses, insulin sensitivity and selected metabolic parameters in obese and insulin-resistant ponies during a body weight reduction programme (BWRP).Sixteen obese ponies (mean body condition score of 7.8±1.5 on a scale of 1-9; and a mean cresty neck score (CNS) of 3.6±1.0 on a scale of 0-5) were assigned to a randomized, double-blind, placebo-controlled study. During a BWRP lasting 14 weeks, the ponies were fed 1.0-1.2 kg hay/100 kg body weight (BW) daily and 100 g grass meal (estimated energy intake: 7.0-8.3 MJ/DE/100 kg BW) and moderately exercised for 45 min 6 days a week. Eight ponies received l-carnitine supplementation (1.3 g/100 kg BW, twice a day), and 8 ponies received a placebo supplement. A frequently sampled intravenous glucose tolerance test was used to assess insulin sensitivity. Routine blood samples were collected for analysis of glucose, insulin, leptin, urea, beta-hydroxybutyrate, free fatty acids (FFA) and triglycerides (TG). Ponies lost approximately 1% BW per week over the BWRP (time: P<0.01, l-carnitine supplementation: P=0.79). BW losses were accompanied by a significant improvement in insulin sensitivity (time: P<0.01, l-carnitine supplementation: P=0.39). Significant time-related decreases were observed for plasma glucose, serum insulin, and leptin, while significant increases were observed for serum urea, FFA, and TG during the BWRP, without any further improvement by l-carnitine supplementation. Energy intake of 7 MJ/100 kg BW results in BW losses, thereby improving insulin sensitivity and glucose metabolism. l-carnitine supplementation does not further improve glucose or fat metabolism.