Effect of dietary n-6 and n-3 polyunsaturated fatty acids on peroxidizability of lipoproteins in steers.
The susceptibility of major plasma lipoproteins to lipoperoxidation was studied in relation to the FA composition of their neutral and polar lipids in steers given PUFA-rich diets. Two trials used, respectively, 18 ("sunflower" experiment, S) or 24 ("linseed" experiment, L) crossbred Salers x Charolais steers. Each involved three dietary treatments over a 70-d period: a control diet (CS or CL diets) consisting of hay and concentrate, or the same diet supplemented with oilseeds (4% diet dry matter) fed either as seeds (SS or LS diets) or continuously infused into the duodenum (ISO or ILO diets). Compared with control diets, ISO and ILO treatments tended to decrease the resistance time of LDL and HDL classes to peroxidation, mainly owing to the enrichment of their polar and neutral lipids with PUFA. With diets SS and LS, sensitivity of major lipoprotein classes (LDL, light and heavy HDL) was not affected because ruminal hydrogenation of dietary PUFA decreased their incorporation into lipoparticles. ISO and ILO treatments induced a more important production of conjugated dienes and hydroperoxides generated by peroxidation in the three lipoprotein classes due to the higher amounts of PUFA esterified in lipids of the core and the hydrophilic envelope of particles. The production of malondialdehyde (MDA) increased in steers fed linseed supplements, indicating that MDA production did not occur with linoleic acid provided by sunflower oil supplements. Thus, plasma peroxidation of PUFA generates toxic products in steers fed diets supplemented with PUFA and can be deleterious for the health of the animal during long-term treatment.
Institut National de la Recherche Agronomique, Research Unit on Herbivores, Nutrients and Metabolisms Group, Research Centre of Clermont-Ferrand/rheix, 63122 Saint Genès-Champanelle, France.
Valérie
V
Scislowski
Dominique
D
Bauchart
Dominique
D
Gruffat
Paul-Michel
PM
Laplaud
Denys
D
Durand
D000818:Animals; D002417:Cattle; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D043371:Fatty Acids, Omega-6 / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D008043:Linseed Oil / Q000008:administration & dosage / Q000633:toxicity; D015227:Lipid Peroxidation / Q000187:drug effects*; D008074:Lipoproteins / Q000097:blood*; D008297:Male; D010938:Plant Oils / Q000008:administration & dosage / Q000633:toxicity; D000074242:Sunflower Oil; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
D004042:Dietary Fats, Unsaturated; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D008074:Lipoproteins; D010938:Plant Oils; D000074242:Sunflower Oil; D017392:Thiobarbituric Acid Reactive Substances; D008043:Linseed Oil