title: Dietary fish oil dose- and time-response effects on cardiac phospholipid fatty acid composition.
abstract: Fish consumption is associated with reduced cardiovascular mortality, and elevated myocardial long-chain n-3 polyunsaturated FA (PUFA) content is implicated in this cardioprotection. This study examined the dose and time responses for incorporation of n-3 PUFA into cellular membranes in rats fed fish oil (FO)-containing diets. For the time course study, rats were fed a 10% FO diet for periods ranging from 0 to 42 d, after which myocardial and erythrocyte membrane fatty acid composition was determined. For the dose response study, rats (n = 3) were fed 0, 1.25, 2.5, 5, or 10% FO for 4 wk, with myocardial, erythrocyte, and skeletal muscle membrane FA determined. Myocardial DHA (22:6n-3) levels doubled in 2 d, stabilizing at levels approximately 200% higher than control after 28 d feeding with 10% FO. By comparison, DHA levels doubled after 4 wk of 1.25% FO feeding. In myocardium and skeletal muscle, EPA (20:5n-3) levels remained low, but in erythrocytes EPA levels reached 50% of DHA levels. The n-3 PUFA were incorporated at the expense of n-6 PUFA in myocardium and skeletal muscle, whereas erythrocytes maintained arachidonic acid levels, and total n-3 PUFA incorporation was lower. This study shows that low doses of FO produce marked changes in myocardial DHA levels; maximal incorporation takes up to 28 d to occur; and while erythrocytes are a good indicator of tissue n-3 incorporation in stable diets, they vary greatly in their time course and pattern of incorporation.
authors.affiliation: Smart Foods Center, Department of Biomedical Science, University of Wollongong, Wollongong, NSW 2522, Australia.
authors.forename: Alice J
authors.initials: AJ
authors.lastname: Owen
authors.forename: Beata A
authors.initials: BA
authors.lastname: Peter-Przyborowska
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Hoy
authors.forename: Peter L
authors.initials: PL
authors.lastname: McLennan
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000737:chemistry / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis*; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology; D005395:Fish Oils / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism; D009206:Myocardium / Q000737:chemistry* / Q000378:metabolism; D010743:Phospholipids / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D010743:Phospholipids