Effect of L-carnitine on weight loss and body composition of rats fed a hypocaloric diet

Background/Aims: Several studies have been published in recent years which suggest that L-carnitine supplementation can influence the lipid metabolism in some species and can also affect body composition of growing animals. Only few results are available so far on the effect of L-carnitine supplementation on weight reduction and body composition of animals fed an energy deficient diet. The aim of this study was therefore to investigate whether L-carnitine supplementation combined with an energy-deficient diet can influence weight development and body composition. Methods: An experiment was conducted with 36 rats with an initial body weight of about 460 g. One-third of the rats were killed, the remainder were divided into two groups (control group, treated group) and fed a semi synthetic diet at an energy level of about half of the rats' maintenance requirement. The basal diet was essentially carnitine free. The diet of the treated group was supplemented with L-carnitine (5 g/kg). The feeding period extended over 23 days. Experimental parameters were weight loss, composition of carcass and weights of the fat pads surrounding the kidneys, intestine and testes; several clinico-chemical plasma parameters were also determined. Results: As was to be expected, the rats lost a considerable amount of weight on the energy-reduced diet. At the same time a shift occurred in the ratio of fat to protein in favour of protein in the carcass, leading to a marked reduction of body fat levels and a slight reduction of protein levels. There were, however, no significant differences between the control group and the treated group (with L-carnitine supplementation) with regard to any of these parameters. The clinico-chemical parameters measured in plasma (glucose, triglycerides, total cholesterol, free fatty acids, 3-hydroxybutyric acid) also showed no differences between the groups. Conclusions: The rat model used here did not show a positive effect of L-carnitine supplementation on weight loss and body composition of rats fed an energy-deficient diet. The animals' endogenous carnitine synthesis was obviously adequate to ensure efficient P-oxidation of fatty acids during the catabolic phase.