title: Octanoate and nonaoate oxidation increases 50-80% over the first two days of life in piglet triceps brachii and gracilis muscle strips.
abstract: An in vitro muscle strip incubation system was developed to measure the rate of catabolism of 1 mmol/L [1-(14)C]octanoate, 1 mmol/L [1-(14)C]nonanoate, 1 mmol/L [9-(14)C]nonanoate, and 10 mmol/L [U-(14)C]glucose by measuring the recovery of (14)CO(2). Muscle strips (13 mm × 1.5 mm, ~50 mg) were isolated from triceps brachii and gracilis muscles of newborn and 2-d-old, small (<950 g) and large (>1450 g) piglets. The position of the (14)C label in the substrate affected the rate and amount of recovery in (14)CO(2). Therefore, comparisons were made between age groups (0 vs. 2 d old) within substrates but limited across substrates to comparisons of [1-(14)C]-labeled fatty acids. The medium-chain fatty acid (MCFA) oxidation rates [pmol/(h · mg)] in muscle strips isolated from piglets from the 2 weight groups (<950 and >1450 g) did not differ (P > 0.99), there was a trend towards a difference between triceps brachii and gracilis muscle (P = 0.09; data not shown), and there were no significant interactions involving pig weight or muscle type; therefore, results were pooled across these factors. During the first 2 d of life, MCFA oxidation [pmol/(h • · mg muscle strip)] increased (P < 0.05) 50-80%, but the glucose oxidation rate did not change (P > 0.82). By d 2, the oxidation rate of nonanoate as represented by the one carbon was 25% greater than for octanoate (P < 0.05). The conversion of [9-(14)C]nonanoate to (14)CO(2) indicated that muscle had the capacity to oxidize the propionyl-CoA produced by β-oxidation of nonanoate and that odd-chain C-9 MCFA provided anabolic carbon to the citric acid cycle.
authors.affiliation: Department of Nutritional Sciences, University of Wisconsin, Madison, WI, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Tetrick
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Crenshaw
authors.forename: Norlin J
authors.initials: NJ
authors.lastname: Benevenga
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001835:Body Weight; D002210:Caprylates / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D013552:Swine / Q000378:metabolism*
chemical_list: D002210:Caprylates; D005227:Fatty Acids; C008776:pelargonic acid; C031492:octanoic acid