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The purpose of this research is to determine the effects of vitamin E and C (100 and 400 ppm. respectively), added to layer hen rations including 4% oil sources (sunflower oil and fish oil) on egg yolk fatty acid composition and malondialdehyde (MDA) level. In this study, 108 layer hens (ISA-Brown) at 69 weeks of age were used. They were divided into 6 groups, each including 18 birds. The diets of the groups were sunflower oil (SFO). sunflower oil + vitamin E (SFO + E), sunflower oil + vitamin C (SFO + C), fish oil (FO). fish oil + vitamin E (FO + E) and fish oil + vitamin C (FO + C), respectively. The research lasted 56 days.
The lowest saturated fatty acids (SFA) levels were found in SFO + E group and the highest level was in FO + E group. Egg yolk monounsaturated fatty acids (MUFA) levels showed a decrease tendency in the fish and sunflower oil groups. On the other hand, polyunsaturated fatty acids (PUFA) and n-6 levels in yolk were found lower in fish oil supplemented groups compared to the sunflower oil groups. Dietary sunflower oi! increased egg yolk linoleic acid level. Egg yolk n-3 levels were found higher in fish oil groups than the sunflower oil groups. Dietary fish oil increased egg yolk a-linolenic acid, eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) levels. Dietary sunflower oil increased egg yolk n-6/n-3 ratio although dietary fish oil decreased this ratio evidently.
Eggs collected in the periods (start of the experiment and 28. days) except at the 8. week, MDA levels were found lower in sunflower oil groups compared to fish oil groups (p<0.001). Yolk MDA levels obtained from the fish oil and sunflower oil group at 4. week decreased with supplementation of vitamin E and C.