Performance and bone mineralisation in broiler chicks fed on diets with different concentrations of cholecalciferol at a constant ratio of calcium to non-phytate phosphorus

Abstract

1. An experiment was conducted with broiler female chicks (720) to study the effects of graded concentrations (7⋅5, 15, 22⋅5 or 30 µg/kg) of cholecalciferol (CC) in diets containing varying levels of calcium (Ca) and non-phytate phosphorus (NPP) at a 2:1 ratio (4:2, 5:2⋅5, 6:3 or 7:3⋅5 g/kg, respectively), on the performance (2–35 d of age), bone mineralisation and mineral (Ca, P, Mn, Fe, Cu) concentration in excreta.

2. Body weight gain, food intake, tibia density and tibia ash increased, and leg abnormality score decreased with dietary increase of CC from 7⋅5 to 30 µg at 4 g Ca and 2 g NPP. However, this improvement was not comparable with the birds receiving the highest concentrations of CC, Ca and NPP (30 µg, 7 g and 3.5 g, respectively/kg diet).

3. Significant improvements in the majority of parameters noted with increasing CC up to 22⋅5 µg at 5 g Ca and 2⋅5 g NPP/kg, which was comparable to those fed the highest levels of CC, Ca and NPP.

4. Concentrations of Ca, P, Mn, Fe and Cu in excreta decreased significantly with increasing CC at all Ca:NPP ratios tested.

5. The predicted requirement of CC for most of the parameters ranged between 16⋅25 and 25 µg/kg diet at 5 g Ca and 2⋅5 g NPP.

6. Considering the performance, bone mineralisation, and mineral concentration in excreta, it can be concluded that Ca and NPP levels in broiler diet could be reduced to 5 and 2⋅5 g, respectively, while maintaining CC at 25 µg/kg.

Acknowledgement

The authors wish to thank the Indian Council of Agricultural Research, New Delhi, India for funding this study under the Young Scientist Award Scheme.