title: Incorporation of n-3 fatty acids into plasma and liver lipids of rats: importance of background dietary fat.
abstract: The health benefits of long-chain n-3 PUFA (20:5n-3 and 22:6n-3) depend on the extent of incorporation of these FA into plasma and tissue lipids. This study aimed to investigate the effect of the background dietary fat (saturated, monounsaturated, or n-6 polyunsaturated) on the quantitative incorporation of dietary 18:3n-3 and its elongated and desaturated products into the plasma and the liver lipids of rats. Female weanling Wistar rats (n = 54) were randomly assigned to six diet groups (n = 9). The fat added to the semipurified diets was tallow (SFA), tallow plus linseed oil (SFA-LNA), sunola oil (MUFA), sunola oil plus linseed oil (MUFA-LNA), sunflower oil (PUFA), or sunflower oil plus linseed oil (PUFA-LNA). At the completion of the 4-wk feeding period, quantitative FA analysis of the liver and plasma was undertaken by GC. The inclusion of linseed oil in the rat diets increased the level of 18:3n-3, 20:5n-3, and, to a smaller degree, 22:6n-3 in plasma and liver lipids regardless of the background dietary fat. The extent of incorporation of 18:3n-3, 20:5n-3, and 22:5n-3 followed the order SFA-LNA > MUFA-LNA > PUFA-LNA. Levels of 22:6n-3 were increased to a similar extent regardless of the type of major fat in the rat diets. This indicates that the background diet affects the incorporation in liver and plasma FA pools of the n-3 PUFA with the exception of 22:6n-3 and therefore the background diet has the potential to influence the already established health benefits of long-chain n-3 fatty acids.
authors.affiliation: Nutrition & Dietetics, University of Newcastle, New South Wales, Australia.
authors.forename: Lesley K
authors.initials: LK
authors.lastname: MacDonald-Wicks
authors.forename: Manohar L
authors.initials: ML
authors.lastname: Garg
mesh_terms: D000818:Animals; D002849:Chromatography, Gas; D004041:Dietary Fats / Q000378:metabolism*; D005223:Fats / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000032:analysis* / Q000378:metabolism; D005260:Female; D008043:Linseed Oil / Q000378:metabolism; D008055:Lipids / Q000097:blood / Q000737:chemistry; D008099:Liver / Q000737:chemistry*; D010938:Plant Oils / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D000074242:Sunflower Oil
chemical_list: D004041:Dietary Fats; D005223:Fats; D015525:Fatty Acids, Omega-3; D008055:Lipids; D010938:Plant Oils; D000074242:Sunflower Oil; D008043:Linseed Oil; C013698:tallow