Abstract
To determine the effects of normal and low dietary calcium (Ca) and phosphorus (P) levels and 25-hydroxycholecalciferol (25-OH-D(3)) supplementation on performance, serum antioxidant status, meat quality, and bone properties of broilers, 224 1-day-old Arbor Acre male broilers were used in this study. Broilers were allotted randomly to 1 of 4 treatments in a 2 × 2 factorial arrangement that included normal or low Ca and P diet with or without 69 μg/kg 25-OH-D(3). The trial consists of a starter phase from day 1 to 21 and a grower phase from day 22 to 42. Dietary 25-OH-D(3) supplementation increased (P < 0.05) average daily weight gain from day 22 to 42 and decreased feed conversation ratio from day 22 to 42 and day 0 to 42. On day 21, 25-OH-D(3) increased serum concentrations of total antioxidant capacity (T-AOC), catalase (CAT), and glutathione peroxidase in broilers fed low Ca and P diet (Interaction, P < 0.05). 25-hydroxycholecalciferol significantly decreased serum malondialdehyde concentration. Dietary Ca and P deficiencies significantly decreased serum Ca and P concentrations and increased serum parathyroid hormone (PTH) concentration, and serum Ca and 25-OH-D(3) concentrations were significantly increased by 25-OH-D(3) supplementation. On day 42, serum T-AOC and CAT concentrations were decreased by dietary Ca and P deficiencies without 25-OH-D(3) (Interaction, P < 0.05) and unaffected by dietary Ca and P deficiencies with 25-OH-D(3). Dietary Ca and P deficiencies significantly decreased Ca, P, and alkaline phosphatase concentrations and increased PTH concentration in serum. Dietary 25-OH-D(3) increased (P < 0.05) serum Ca and 25-OH-D(3) concentrations and decreased (P < 0.05) serum tartrate-resistant acid phosphatase concentration. The interaction between CaP level and 25-OH-D(3) was observed (P < 0.05) for tibial Ca content and femoral bone density. 25-hydroxycholecalciferol significantly increased tibial breaking strength. These data indicated that 25-OH-D(3) supplementation at 69 μg/kg increased growth performance in some periods, enhanced serum antioxidant capacity, and improved bone mineralization and breaking strength of broilers.