Bone sampling and analyses
To assess bone parameters, the left legs of two birds per experimental unit were collected at 7, 21 and 42 d of age and remained frozen (−20°C) until processing.
Once the legs were thawed, the muscle tissue was removed using scissors and tweezers, separating the femur and tibia. The bones were subsequently weighed on an analytical balance (g±0.0001), and the mid-leg length and diameter were measured using digital calipers (mm). The Seedor index (Seedor et al., 1991) was calculated using the formula Seedor index = bone weight (mg)/bone length (mm).
Bone strength analysis was performed using fresh thawed bones. The mechanism consisted of a base that supports the epiphyses of the bone and a force was applied to the central region of the bone. The values were expressed in kilograms-force (kgf).
Following the testing for bone strength, the bones were prepared for the determination of mineral content. The bones were defatted in petroleum ether, dried in a forced air oven, ground and weighed on an analytical balance (0.001 g). They were then dried at 105°C for 12 h, weighed after cooling and calcined in a muffle furnace at 600°C to obtain the ashes, following the methodology described by Oliveira (2006). The ash content of calcium and phosphorus in bone, were performed according to the methodology described b