Supplementation of L-carnitine in pigs: absorption of carnitine and effect on plasma and tissue carnitine concentrations.

This study was performed to investigate the bioavailability of carnitine supplements and their effects on the carnitine status of pigs. Seven groups of young pigs with an average body weight of 10 kg were fed a basal diet or the same diets supplemented with 25, 50, 100, 200, 500 or 1000 mg of L-carnitine per kg for 20 days. Absorption rate of the supplemented carnitine in the small intestine, assessed by the use of titanium dioxide as an indigestible indicator, was greater than 95% for the lower doses (25, 50, 100 mg/kg) and greater than 90% for the higher doses (200, 500, 1000 mg/kg). Supplementation of carnitine caused a dose-dependent increase of free carnitine, acetyl and total carnitine concentrations in plasma, liver, kidney, heart and skeletal muscle. At the highest dose of 1000 mg/kg, plasma and tissue total carnitine concentrations were 3- to 6-fold higher than in the unsupplemented control group. In conclusion, the present study shows that young pigs have a high capacity to absorb carnitine from the diet. It is also shown that plasma and tissue carnitine concentrations in young pigs can be markedly increased by supplementation of carnitine.