Özet:

This experiment was carried out to investigate the effects of variant doses of rosemary (Rosmarinus officinalis L.) essential oils (REO), vitamin E (α‐tocopheryl acetate) and antibiotic (chlortetracyclin) on the concentration of vitamin E, fatty acid composition, cholesterol levels in the yolk. In this experiment, 32 weeks old Bovans genotype and 240 white laying hens were randomly separated to six treatment groups with five replicas. While the control group was fed with basal diet the treatment groups were supplemented with 500 mg/kg antibiotics; 200 mg/kg vitamin E; 100, 200, and 300 mg/kg REO to basal diet for 90 consecutive days. The results showed that addition of antibiotics, vitamin E and REO to the diet had no effects on egg cholesterol, while fatty acid composition and vitamin E contents of the yolk were significantly affected. Addition of 100 mg/kg REO to the diet increased total mono unsaturated fatty acids (MUFA) by increasing oleic acid level but decreased Polyunsaturated fatty acids (PUFA) by decreasing linoleic acid content of the yolk. Addition of 200 mg/kg vitamin E to the diet significantly increased vitamin E content of egg. The study showed that the changes in yolk fatty acid composition and vitamin E content due to the feed additives, could affect positively in chemical composition of eggs. In conclusion, 100 mg/kg REO and 200 mg/kg vitamin E supplementation to the diet might cause high antioxidant capacity and could help to produce eggs that were more resistant to lipid oxidation.

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