A practical example of the role calcium (Ca) has on phosphorus (P) digestibility was demonstrated in a recent broiler trial at the University of Warmia and Mazury, Poland.
Feed was reformulated with 1,000 FTU/kg of OptiPhos® Plus 5000 G while 1,500 EPU/kg of Hostazym® X 15000 was added on top.
The three different Ca treatments were:
The overall technical performance of the birds was very good (the European Production Efficiency Factor (EPEF) was > 500) showing the potential of using a double dose of OptiPhos® Plus combined with Hostazym® X on top to enhance broiler performance.
The following effects of Ca on performance were noted (Figure 1):
Figure 1. Effect of lowering Ca levels on body weight and feed conversion at day 35. Values with a different superscript (a,b) are significantly different at p < 0.05
The effect of reducing Ca on the Ca and P digestibility (at day 35), and bone ash analysis (at day 21; Table 1) showed that:
The fact that low Ca levels optimized technical performance, but tended to reduce bone ash, demonstrates that the Ca requirement for optimal bone growth is higher than the Ca requirement for optimal performance.
Table 1. Ileal digestibility of Ca and P, tibia ash content, and Ca and P content in tibia ash
Conclusion