title: High levels of dietary unsaturated fat decrease alpha-tocopherol content of whole body, liver, and plasma of chickens without variations in intestinal apparent absorption.
abstract: An experiment was designed to assess the effect of dietary unsaturated fat inclusion level on alpha-tocopherol apparent absorption and deposition in broiler chickens at 2 ages (20 and 39 d). The dietary fat was a mixture of linseed and fish oil, rich in polyunsaturated fatty acids (PUFA). The experimental treatments were the result of 4 levels of supplementation with alpha-tocopheryl acetate (0, 100, 200, and 400 mg/kg; E0, E100, E200, and E400 treatments, respectively) and 4 dietary oil inclusion levels (2, 4, 6, and 8%; O2, O4, O6, and O8 treatments respectively). Almond husk was used as an energy dilutor in the high-fat diets. Apparent absorption of total fatty acids was high in all treatments averaging 88% and was higher with high fat dietary inclusion level. alpha-Tocopheryl acetate hydrolysis and apparent absorption of alpha-tocopherol were similar in both ages and were not affected by fat inclusion level, except for a reduction of the absorption in the low-fat diet (O2) in the E100 treatment at 20 d of age. Despite this lack of differences in hydrolysis and absorption, higher-fat PUFA diets induced lower concentrations of free alpha-tocopherol in the excreta, at high alpha-tocopherol doses, suggesting an increase in the destruction of alpha-tocopherol by lipid oxidation in the gastrointestinal tract. Similarly, total and hepatic alpha-tocopherol deposition was lower in the birds fed high-PUFA diets in the E200- and E400-supplemented birds, possibly due to a destruction of vitamin E when protecting these PUFA from lipid peroxidation. alpha-Tocopherol concentration in liver and, to a lesser extent, in plasma was a useful indicator of the degree of response of this vitamin to different factors that can affect its bioavailability; however, in the present experiment, CV were too high to use liver and plasma concentrations as estimators of total body vitamin E.
authors.affiliation: Grup de Recerca en Nutrició, Maneig i Benestar Animal, Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Villaverde
authors.forename: M D
authors.initials: MD
authors.lastname: Baucells
authors.forename: E G
authors.initials: EG
authors.lastname: Manzanilla
authors.forename: A C
authors.initials: AC
authors.lastname: Barroeta
mesh_terms: D000222:Adaptation, Physiological; D000375:Aging / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001682:Biological Availability; D002645:Chickens / Q000378:metabolism*; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005395:Fish Oils; D006868:Hydrolysis; D007408:Intestinal Absorption / Q000187:drug effects / Q000502:physiology; D008043:Linseed Oil; D015227:Lipid Peroxidation; D008099:Liver / Q000378:metabolism*; D011897:Random Allocation; D024502:alpha-Tocopherol / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics
chemical_list: D000975:Antioxidants; D004042:Dietary Fats, Unsaturated; D005395:Fish Oils; D008043:Linseed Oil; D024502:alpha-Tocopherol