title: Membrane fatty acid composition of rat skeletal muscle is most responsive to the balance of dietary n-3 and n-6 PUFA.
abstract: The present study quantifies the relationships between diet fatty acid profile and fatty acid composition of rat skeletal muscle phospholipids. Young adult male Sprague-Dawley rats were fed, for 8 weeks, on one of twelve moderate-fat diets (25 % of total energy) differing only in fatty acid profile. SFA content ranged from 8-88 % of total fatty acids, MUFA 6-65 %, total PUFA 4-81 %, n-6 PUFA 3-70 % and n-3 PUFA 1-70 %. Diet PUFA included only essential fatty acids 18 : 2n-6 and 18 : 3n-3. The balance between n-3 and n-6 PUFA (PUFA balance) in the diet ranged from 1 : 99 to 86 : 14 % n-3 PUFA:n-6 PUFA. The slope of muscle phospholipid composition plotted against diet composition quantifies the response of muscle membrane composition to dietary fat (0, no response; 1, complete conformity with diet). The resulting slopes were 0.02 (SFA), 0.10 (PUFA), 0.11 (MUFA), 0.14 (n-3 PUFA) and 0.23 (n-6 PUFA). The response to PUFA balance was biphasic with a slope of 0.98 below 10 % diet PUFA balance and 0.16 above 10 %. Thus, low diet PUFA balance has greater influence on muscle composition than 18-carbon n-3 or n-6 PUFA individually. Equations provided may allow prediction of muscle composition for other diet studies. Diet PUFA balance dramatically affects muscle 20 : 4n-6 and 22 : 6n-3. This may have significant implications for some disease states in human subjects.
authors.affiliation: Metabolic Research Centre, University of Wollongong, Wollongong, NSW 2522, Australia. ska454@uow.edu.au
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Abbott
authors.forename: Paul L
authors.initials: PL
authors.lastname: Else
authors.forename: A J
authors.initials: AJ
authors.lastname: Hulbert
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D004032:Diet; D004041:Dietary Fats / Q000378:metabolism*; D005227:Fatty Acids / Q000008:administration & dosage; D015525:Fatty Acids, Omega-3 / Q000378:metabolism*; D043371:Fatty Acids, Omega-6 / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004041:Dietary Fats; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D010743:Phospholipids