Effects of sunflower oil and lard on composition and presence of heavy metals in chicken fats.

In the experimental trial, chicken of hybrid Cobb 500 aging 1 to 42 days were used. Chicken were fed feed greased by sunflower oil and rendered lard. Investigations were performed on rendered chicken fat sampled from different parts of carcasses. Total number of chickens was 60, divided into two groups of 30. From each group, individual samples were taken for analysis. Percentage of fat in the feed used in broiler nutrition was 3% by treatment. Based on the obtained results, an insight into composition and quality of the tested chicken fats was gained. Higher water content was established in rendered chicken fat obtained from chickens fed diets containing rendered lard than in chickens fed diets containing sunflower oil. Highly significant difference (p < 0.001) was established. Statistically highly significant difference (p<0.001) was established in iodine number too, depending on the applied greased feed. Higher value for iodine number was established in chicken fat obtained from chicken fed diets containing sunflower oil (86.01 g J2/100g) than in fat obtained from chickens fed diet containing lard (74.10 g J2/100g). Statistically highly significant difference (p < 0.001) was established concerning saponification number, since the saponification number was higher in fat of chickens fed diets containing lard (193.34 mg KOH/g) compared to nutrition treatmen with feed containing sunflower oil (190.03 mg KOH/g). In samples of rendered fat of chickens from both nutrition treatments, the content of Cd higher then MRL (maximum residue limit) was established (0.07 mg/kg). The values for Pb and Cu in rendered chicken fat in both nutrition treatments were not higher than the established MRLS. The persence of toxic elements in rendered chicken fat might be due to the contamination of chicken feed as well as of the fatts used in the diets.