ABSTRACT This study evaluated the effects of dietary non-phytate phosphorus (NPP) and 1a-hydroxycholecalciferol (1a-OH-D3) on the growth performance, bone mineralization, and carcass traits of 1- to 21-day-old broiler chickens. On the day of hatch, 600 male Ross 308 chicks were weighed and randomly assigned to 12 treatments, with five cages of 10 birds each. A 6 × 2 factorial arrangement was applied, consisting of 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, or 0.45% NPP and 0 or 5 μg/kg of 1a-OH-D3. The basal diet contained 0.52% calcium (Ca) and was not supplemented with vitamin D3. Dietary NPP levels significantly affected growth performance and tibia mineralization (except width) of broilers; by contrast, meat yield and organ relative weight were not influenced by NPP. The inclusion of 1a-OH-D3 improved growth performance, tibia mineralization, and carcass and breast yield, whereas it decreased the relative weights of the liver, heart, and kidney. A significant interaction between NPP and 1a-OH-D3 was observed for body weight gain (BWG), feed efficiency (FE), mortality, serum Ca and P levels, tibia breaking-strength, ash weight, and Ca content, as well as breast yield and heart relative weight. These results suggest that broilers fed with 5 μg of 1a-OH-D3 per kg of diet obtain optimal growth performance and tibia mineralization when dietary NPP level was 0.30% and the analyzed Ca to NPP ratio was 1.97.

ABSTRACTThis study aimed at comparing the growth and mineralization of the femur, tibia, and metatarsus of male and female broiler chicks. On the day of hatch, 100 male and 100 female Ross 308 broiler chicks were transferred stainless cages with 10 birds per cage. On d 7, 14, 21, 28, 35, and 42, five males and five females were sacrificed and their femur, tibia, and metatarsus were collected. Results showed that the tibia was the heaviest and the longest and contained the highest content of ash and calcium (Ca) among the three leg bones. The femur had the greatest diameter. The weight, length, diameter, and ash weight of the femur, tibia, and metatarsus linearly increased with age. The ash, Ca, and phosphorus (P) content in the femur and the tibia quadratically increased with age; by contrast, these parameters in the metatarsus linearly increased with age. The bones grew faster in 1 to 21 d of age. The weight, diameter, and ash weight of the three bones of males were higher than those of females. The Ca to P ratio of the three bones (femur, tibia, and metatarsus) was approximately 2.0:1. These data indicate that there are differences in bone growth and mineralization among the femur, tibia, and metatarsus of male or female broiler chicks.