This study aimed to evaluate the performance and bone parameters of broiler chickens fed on diets with different linseed oil (LO) levels from 1 to 42 days of age. At the initial and growing phases (1 to 21 days and 22 to 42 days of age, respectively) a completely randomized design was used with four linseed oil levels (2.0, 3.5, 5.0 or 6.5%), six replicates and 50 birds per experimental unit. The birds were fed diets with different linseed oil levels (2.0; 3.5; 5.0 and 6.5%). A linear effect of linseed oil was observed on tibia absolute diameter and weight but the femur was not influenced by linseed oil inclusion in the diet. Data revealed significant interaction between age and linseed oil levels for the Seedor index, demonstrating that the positive and negative effects of the highest linseed oil levels observed for femur and tibia, respectively, increased at the end of the growth phase. The femur and tibia growth and quality parameters presented cubic performance in function of age. The inclusion of linseed oil and age showed a quadratic effect on the femur ash weight. The ash concentration was positively influenced by the levels of linseed oil in the diets but the best results were shown after 28 days. The bone strength was not influenced by the different linseed oil levels, but showed cubic performance in function of age. However, there was significant age × linseed oil level interaction for bone mineral density, so that the best results with linseed oil addition were observed at the initial rearing stage of the birds. It was concluded that diets with 6.5% linseed oil are beneficial to growth and mineralization of long bones in broiler chickens.
ash; femur; mineral density; Seedor index; strength; tibia
