title: Effect of dietary oregano oil and alpha-tocopheryl acetate supplementation on iron-induced lipid oxidation of turkey breast, thigh, liver and heart tissues.
abstract: Twenty-five 12-week-old turkeys randomly divided into five groups were given a basal diet, or a basal diet supplemented with 200 mg alpha-tocopheryl acetate/kg, or 100 mg oregano oil/kg or 200 mg oregano oil/kg, or 100 mg oregano oil plus 100 mg alpha-tocopheryl acetate/kg diet, for 4 weeks prior to slaughter. Breast, thigh, liver and heart tissues were subjected to iron-induced lipid oxidation, the extent of which was determined by third-order derivative spectrophotometry. Results showed that dietary oregano oil at the inclusion level of 200 mg oregano oil/kg diet was more effective in delaying lipid oxidation compared with the inclusion level of 100 mg/kg, but equivalent to the inclusion of 200 mg alpha-tocopheryl acetate/kg diet, which in turn was inferior to the combined inclusion of 100 mg oregano oil plus 100 mg alpha-tocopheryl acetate/kg, which was superior to all dietary treatments. Thigh tissue was more susceptible to oxidation than breast tissue, although it contained alpha-tocopherol at higher concentrations. Also, lipid oxidation in heart was relatively high, although it contained the highest alpha-tocopherol levels. This indicates that tissue alpha-tocopherol is one important factor influencing the level of lipid oxidation, but the distribution of lipids, iron and oregano oil in tissues must also be taken into consideration. Tissue alpha-tocopherol levels responded to dietary intake of 30-200 mg alpha-tocopheryl acetate/kg in the order heart > liver > thigh > breast. Breast, thigh and heart tissues from the oregano groups presented significantly (p < 0.05) higher levels of alpha-tocopherol compared with the control, the increase being positively correlated with the supplementation level. The increased levels of alpha-tocopherol in these tissues indicated that the dietary oregano oil exerted a protective action on alpha-tocopherol.
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D001682:Biological Availability; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D050356:Lipid Metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008315:Malondialdehyde / Q000378:metabolism; D009822:Oils, Volatile / Q000008:administration & dosage; D031341:Origanum / Q000737:chemistry*; D010084:Oxidation-Reduction; D010938:Plant Oils / Q000008:administration & dosage*; D011897:Random Allocation; D013053:Spectrophotometry / Q000662:veterinary; D014018:Tissue Distribution; D024505:Tocopherols; D014422:Turkeys / Q000378:metabolism*; D024502:alpha-Tocopherol / Q000008:administration & dosage* / Q000031:analogs & derivatives*
chemical_list: D000975:Antioxidants; D009822:Oils, Volatile; D010938:Plant Oils; D008315:Malondialdehyde; D024502:alpha-Tocopherol; D024505:Tocopherols