Influence of dietary supplementation with (L)-carnitine on metabolic rate, fatty acid oxidation, body condition, and weight loss in overweight cats.
OBJECTIVE
To investigate the influence of dietary supplementation with l-carnitine on metabolic rate, fatty acid oxidation, weight loss, and lean body mass (LBM) in overweight cats undergoing rapid weight reduction.


METHODS
32 healthy adult neutered colony-housed cats.


METHODS
Cats fattened through unrestricted ingestion of an energy-dense diet for 6 months were randomly assigned to 4 groups and fed a weight reduction diet supplemented with 0 (control), 50, 100, or 150 μg of carnitine/g of diet (unrestricted for 1 month, then restricted). Measurements included resting energy expenditure, respiratory quotient, daily energy expenditure, LBM, and fatty acid oxidation. Following weight loss, cats were allowed unrestricted feeding of the energy-dense diet to investigate weight gain after test diet cessation.


RESULTS
Median weekly weight loss in all groups was ≥ 1.3%, with no difference among groups in overall or cumulative percentage weight loss. During restricted feeding, the resting energy expenditure-to-LBM ratio was significantly higher in cats that received l-carnitine than in those that received the control diet. Respiratory quotient was significantly lower in each cat that received l-carnitine on day 42, compared with the value before the diet began, and in all cats that received l-carnitine, compared with the control group throughout restricted feeding. A significant increase in palmitate flux rate in cats fed the diet with 150 μg of carnitine/g relative to the flux rate in the control group on day 42 corresponded to significantly increased stoichiometric fat oxidation in the l-carnitine diet group (> 62% vs 14% for the control group). Weight gain (as high as 28%) was evident within 35 days after unrestricted feeding was reintroduced.


CONCLUSIONS
Dietary l-carnitine supplementation appeared to have a metabolic effect in overweight cats undergoing rapid weight loss that facilitated fatty acid oxidation.
Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA. sac6@cornell.edu
Sharon A
SA
Center
Karen L
KL
Warner
John F
JF
Randolph
Gregory D
GD
Sunvold
Jason R
JR
Vickers
D000818:Animals; D002153:Calorimetry, Indirect; D002331:Carnitine / Q000494:pharmacology*; D002371:Cat Diseases / Q000178:diet therapy* / Q000378:metabolism; D002415:Cats; D019587:Dietary Supplements; D004734:Energy Metabolism / Q000502:physiology; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D008297:Male; D050177:Overweight / Q000178:diet therapy / Q000378:metabolism / Q000662:veterinary*; D011897:Random Allocation; D018709:Statistics, Nonparametric; D015431:Weight Loss / Q000502:physiology
D005227:Fatty Acids; D002331:Carnitine