Figure 3.

Changes in the AID of P with supplementation of phytase using a broken-line analysis. The NC treatment was not included in this model. The breakpoint was 59 FTU/d of phytase supplementation when AID of P was 42%. The equation for AID of P was Y = 42−0.08318 × zl; if phytase supplementation is ≥breakpoint, then z; = 0; if phytase supplementation is <breakpoint, then zl = breakpoint—phytase intake. Values for phytase activity were based on the analyzed values. The p-value for the intercept was <0.05, for the slope was 0.077 and for the breaking point was <0.05 (confidence interval 95%: 58.55 to 60.59; SE: 0.14). The breakpoint was converted from 59 FTU/d to 952 FTU/kg feed by dividing with the overall average feed intake (0.062 kg/d).