title: Greater effect of diet than exercise training on the fatty acid profile of rat skeletal muscle.
abstract: We determined the interaction of diet and exercise-training intensity on membrane phospholipid fatty acid (FA) composition in skeletal muscle from 36 female Sprague-Dawley rats. Animals were randomly divided into one of two dietary conditions: high-carbohydrate (64.0% carbohydrate by energy, n = 18) or high fat (78.1% fat by energy, n = 18). Rats in each diet condition were then allocated to one of three subgroups: control, which performed no exercise training; low-intensity (8 m/min) treadmill run training; or high-intensity (28 m/min) run training. All exercise-trained rats ran 1,000 m/session, 4 days/wk for 8 wk and were killed 48 h after the last training bout. Membrane phospholipids were extracted, and FA composition was determined in the red and white vastus lateralis muscles. Diet exerted a major influence on phospholipid FA composition, with the high-fat diet being associated with a significantly (P < 0.01) elevated ratio of n-6/n-3 FA for both red (2.7-3.2 vs. 1.0-1.1) and white vastus lateralis muscle (2.5-2.9 vs. 1.2). In contrast, alterations in FA composition as a result of either exercise-training protocol were only minor in comparison. We conclude that, under the present experimental conditions, a change in the macronutrient content of the diet was a more potent modulator of skeletal muscle membrane phospholipid FA composition compared with either low- or high-intensity treadmill exercise training.
authors.affiliation: Metabolic Research Centre, Department of Biomedical Sciences, University of Wollongong, New South Wales, Australia.
authors.forename: Nigel
authors.initials: N
authors.lastname: Turner
authors.forename: Jong Sam
authors.initials: JS
authors.lastname: Lee
authors.forename: Clinton R
authors.initials: CR
authors.lastname: Bruce
authors.forename: Todd W
authors.initials: TW
authors.lastname: Mitchell
authors.forename: Paul L
authors.initials: PL
authors.lastname: Else
authors.forename: A J
authors.initials: AJ
authors.lastname: Hulbert
authors.forename: John A
authors.initials: JA
authors.lastname: Hawley
mesh_terms: D000818:Animals; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004041:Dietary Fats / Q000008:administration & dosage*; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000379:methods / Q000706:statistics & numerical data; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D005227:Fatty Acids