Oral absorption and disposition of alpha-Linolenic, rumenic and vaccenic acids after administration as a naturally enriched goat dairy fat to rats

Although there is extensive information describing the positive biological effects of conjugated linoleic acid and its main isomer rumenic acid (RA; C18:2 cis 9, trans 11), and alpha-linolenic acid (ALA) and vaccenic acid (TVA), data about their bioavailability are not available. In this work, we investigated the oral absorption and disposition of these fatty acids in Wistar rats. A naturally enriched goat dairy fat (EDF) was obtained by supplementing ruminant diets with oils or oilseeds rich in polyunsaturated fatty acids (PUFA). The EDF was administered orally (single dose of 3000 mg EDF/kg body weight equivalent to 153 mg TVA/kg body weight, 46 mg RA/kg body weight and 31 mg ALA/kg body weight), and serial blood and liver samples were collected and TVA, RA and ALA concentrations determined by GC/MS. The fatty acids TVA, RA and ALA were rapidly absorbed (t1/2a, 0.36, 0.66 and 0.76 h, respectively, for plasma) and slowly eliminated (t1/2β, 17.04, 18.40 and 16.52 h, respectively, for plasma). The maximum concentration (Cmax) was detected in liver > plasma > erythrocyte. Our study shows that when orally administered EDF, its components TVA, RA and ALA were rapidly absorbed and distributed throughout the body by the blood circulation to exert systemic effects.