Six broiler starter diets, based on wheat and soybean meal, were formulated to contain 1.1 2.0, 4.0, 6.0, 8.0 and 10.0 g calcium (Ca)/kg. All diets were equivalent in respect of total and non-phytate phosphorus contents (5.4 and 3.0 g/kg, respectively). The influence of dietary treatments on the growth performance, coefficient of apparent ileal digestibility (CAID) of nitrogen (N), starch, fat and phosphorus (P), Ca retention and apparent metabolisable energy (AME) in broiler starters was evaluated. A total of 288, one-day-old male broilers (Ross 308) were allocated to 36 cages (8 birds/cage), and cages were randomly assigned to 6 dietary treatments. Birds were also provided with a source of Ca in a separate feed trough. Birds fed the diet with 1.1 g Ca/kg gained more (P0.05) feed per unit gain. During d 8 to 14, d 15 to 21, and over the entire trial period of 21 d, birds fed Ca-deficient (6.0 g Ca/kg and less) diets consumed more (P0.05) of dietary Ca on the retention of Ca and ash, AME and toe ash. The present data suggest that feeding broilers low Ca diets with access to a separate Ca source, is advantageous in terms of broiler performance, while maintaining bone mineralisation. The data also demonstrate that the provision of separate Ca source may hold promise for reducing the dietary P contents.
- phytate phosphorus hydrolysis
- nonphytate phosphorus
- phytic acid