Oxidation of polyunsaturated fatty acids leads to primary and secondary oxidation products. Compounds and amounts of these products vary, depending on the oxidative conditions. As these oxidation products have different absorption and biological effects, we performed two different heating treatments on sunflower oil. The first was heating the oil at 190-195"C for 28 h i.e. very oxidised oil); and the other, heating at 60"C for 12 days (i.e. pcroxidiscd oil). In the frame of this study, we compared the fatty acid composition of a refined sunflower oil (fresh oil), the pcroxidiscd oil, the very oxidised oil, and a mixture (1+1) of fresh and very oxidised oil (i.e. oxidised oil). Oil fatty acid compositions were affected by the heating treatments. In to addition, different fatty acid isomers were formed during heating at 190-I95°C and significant differences were found between thcir.contcnt in the sunflower oils. We also studied the effect of feeding broilers with these oils and Zn and tocopherol supplements on the fatty acid composition of their raw dark meat. Various Irons fatty acid isomers increased in dark meat from broilers fed oxidised and very oxidised oils. In addition, discriminant analysis showed that ditrans-CLA content was able to distinguish dark chicken meat from chickens fed sunflower oils heated at 190-195"C
