No abstract

Performance parameters and oxidation of body lipids of broiler chickens were investigated when their diet was supplemented with a commercial preparation of essential oils (Apacox) derived from selected herbs. One hundred and twenty day-old Cobb-500 female chicks were divided into four groups with three replicates each. One group received the basal diet, the control. The three experimental diets consisted of the basal diet to which either 200 mg α-tocopheryl acetate/kg (Toc200 group), Apacox at 0.5 g/kg (Apa0.5 group) or Apacox at 1.0 g/kg diet (Apa1.0 group) was added. At the end of the 42 day feeding period there were no differences in initial and final body weights, daily weight gains, daily feed intakes and feed conversion ratios between treatments, and no mortalities were recorded. It is concluded that the mixture of herbal essential oils exerted no growth-promoting effect when incorporated in the chicken diet. The progress of lipid oxidation was assessed in raw and heat treated breast and thigh muscle at 0, 3, 6 and 9 days of refrigerated storage at 4 o C. Results showed that Apacox retarded lipid oxidation in both raw and heat treated breast and thigh muscles at all time points, with the supplementation level of 1.0 g/kg diet being more effective in retarding lipid oxidation than the 0.5 g Apacox/kg treatment. The retardation offered by Apacox was, however, inferior to that exhibited by α-tocopheryl acetate supplementation. Raw and heat treated thigh muscle samples were more susceptible to oxidation compared to breast muscle, although the latter contained α-tocopherol at markedly lower concentrations.

No abstract

The effects of dietary oregano essential oil and alpha-tocopheryl acetate supplementation on the oxidative stability of long-term frozen stored turkey meat were investigated. Thirty 12-week-old turkeys, randomly divided into five groups, were given a basal diet or a basal diet supplemented with 200 mg of alpha-tocopheryl acetate kg(-1), or 100 or 200 mg of oregano oil kg(-1), or 100 mg of oregano oil plus 100 mg of alpha-tocopheryl acetate kg(-1) for 4 weeks prior to slaughter. Lipid oxidation in breast and thigh meat was assessed after 1, 3, 6, and 9 months of frozen storage at -20 degrees C prior to or following 7 days of refrigerated storage at 4 degrees C. Results showed that oregano oil increased the oxidative stability of breast and thigh meat during the frozen storage. Dietary oregano oil at the inclusion level of 200 mg kg(-1) feed was significantly (p < 0.05) more effective in delaying lipid oxidation compared to the level of 100 mg kg(-1), but equivalent to dietary alpha-tocopheryl acetate supplementation at 200 mg kg(-1), which in turn was inferior to dietary supplementation of 100 mg kg(-1) oregano essential oil plus 100 mg kg(-1) alpha-tocopheryl acetate that was significantly (p < 0.05) superior to all other treatments. Thigh meat was more susceptible to oxidation than breast meat, although the former contained alpha-tocopherol at markedly higher levels. Mean alpha-tocopherol levels in breast and thigh meat from all treatments decreased during the frozen storage, the decrease being sharper between 1 and 3 months of frozen storage for breast and between 3 and 6 months for thigh meat. Oregano oil supplementation increased (p < 0.05) the retention of alpha-tocopherol in meat, the increase being positively correlated with the supplementation level. However, the retention of alpha-tocopherol in meat could only partly elucidate the antioxidant activity exhibited by dietary oregano oil supplementation.

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.

The dietary and post-mortem uses of oregano oil in turkeys to inhibit development of lipid oxidation in breast and thigh meat during refrigerated storage were investigated. Using minced meat, patties were prepared from turkey meat post-mortem added with either 200 mg oregano oil or alpha-tocopherol/kg, meat from turkeys dietary supplemented with either 200 mg oregano oil or alpha-tocopheryl acetate/kg feed, and control meat. All patties were cooked, placed in a refrigerated cabinet at 4 degrees C, and lipid oxidation was assessed by monitoring malondialdehyde formation after 3, 6 and 9 days of storage. Treatments significantly (P<0.05) retarded lipid oxidation in both breast and thigh meat patties at all storage times compared with controls. The dietary supplementation of either oregano oil or alpha-tocopheryl acetate exhibited the highest antioxidative activity compared with the other treatments. Post-mortem addition of either oregano oil or alpha-tocopherol to the minced meat also retarded lipid oxidation in the prepared patties compared with controls; however, this effect was inferior to that of the dietary supplementation even though the post-mortem alpha-tocopherol supplemented meat contained 90-fold more alpha-tocopherol than patties from the dietary supplemented meat. Thigh meat was more susceptible to oxidation than breast meat, although the former contained alpha-tocopherol at markedly higher levels. Supplementing the diet with 200 mg oregano oil/kg, alpha-tocopherol levels in the breast and thigh meat significantly (P<0.05) increased compared with control. This increase could not be attributed to the alpha-tocopherol already present in the oregano oil since post-mortem addition of oregano oil to control breast and thigh meat at the same dose could not actually increase the alpha-tocopherol concentrations.

The effect of intramuscular administration of high (30 mg/kg body weight for 3 days) or very high (300 mg/kg body weight for 3 days) doses of a-tocopherol to Wistar rats subjected to total severe warm hepatic ischemia and reperfusion was investigated. After a 60-minute period of total hepatic ischemia and 120 minutes of reperfusion, animals were killed, and liver samples were taken for determination of malondialdehyde (MDA) and histological examinations. Blood samples were also taken for assay of serum a-tocopherol, alanine transaminase (ALT), aspartate transaminase (AST), and lactic dehydrogenase (LDH). Additional animals were followed for a 7-day survival rate determination. Results showed that ischemia and reperfusion decreased the survival rate to 10%, whereas the levels of AST, ALT, and LDH in serum were increased compared with levels in animals that were sham operated. The MDA concentrations in liver were also increased, from 1.142 to 1.567 nmoles/g, whereas the levels of a-tocopherol in serum were decreased from 10.20 to 1.80 mmol/L. Pretreatment with a-tocopherol increased the viability to 50% and 70%, for the high and very high doses, respectively, and decreased the levels of AST, ALT, and LDH in serum. It also decreased the MDA concentrations in liver to 0.975 and 0.774 nmoles/g for the high and very high doses of a-tocopherol, respectively, whereas it increased the level of a-tocopherol in serum to 11.25 and 13.02 mmol/L for the high and very high doses, respectively. Histological examinations showed protection of the liver parenchyma in the animals treated with a-tocopherol.

No abstract