Dietary L-carnitine enhances the lymphatic absorption of fat and alpha-tocopherol in ovariectomized rats

This study was conducted to determine whether the feeding of dietary L-carnitine (CN) improves the intestinal absorption of fat and alpha-tocopherol (alphaTOH) in ovariectomized (OX) rats. OX adult rats were weight-matched and assigned to 2 groups fed a modified AIN-93G diet containing alphaTOH-stripped soybean oil without (-CN) or with (+CN) supplemental CN at 150 mg/kg diet. At 5 wk, each rat with a lymph cannula was infused intraduodenally at 3.0 mL/h with a lipid emulsion consisting of 565 micromol triolein labeled with (14)C ((14)C-OA), 3.6 micromol alphaTOH, and 396 micromol sodium taurocholate in 24 mL PBS buffer. Lymph was collected hourly for 8 h and analyzed for lipids. The lymphatic absorption of alphaTOH for 8 h in +CN rats (899 +/- 201 nmol) was higher (P < 0.05) than in -CN rats (587 +/- 92 nmol). The absorption of (14)C-OA in +CN rats (53.5 +/- 4.0% dose/8 h) also was increased (P < 0.05) compared with -CN rats (47.6 +/- 5.0% dose/8 h). Lymph flow did not differ between the groups. When bile was diverted but with infusion of sodium taurocholate, the lymphatic absorption of lipids did not differ. The present study provides evidence that dietary CN enhances the rates and amounts of lymphatic absorption of alphaTOH and fat in OX rats. Our findings suggest that dietary CN may influence the process of lipid packaging and absorption by the enterocyte in OX rats, and may explain in part the increased status of alphaTOH in CN-fed animals.