25-Hydroxycholecalciferol As an Alternative to Vitamin D3 in Diets with Different Levels of Calcium for Broilers Reared Under Heat Stress

The objective was to evaluate the effect of dietary 25-hydroxycholecalciferol (25(OH)D3) or vitamin D3 (VitD3) and different total calcium (Ca) levels on performance, carcass characteristics, blood, enzymatic, bone biochemistry broilers reared under heat stress between 1 42 days age. A 504 male, Cobb 500, broiler chickens were distributed in a completely randomized design 2 × 4 factorial arrangement (VitD3 25(OH)D3 four Ca (100, 90, 80 70% recommendations Rostagno et al. (2011)), eight treatments, seven replicates nine per cage. Feed intake feed conversion ratio did not (p>0.05) vary when reduced sources supplemented diets from 21 for chickens. 25 (OH)D3 increased weight gain results (p<0.05). From d, no differences observed yields meat quality, deposition P, alkaline phosphatase concentration. Higher serum (p<0.05) concentrations P found fed with 25(OH)D3. replacement VitD3 reduction 30% negatively affect tibia at age, stress.