Table 5.

Growth performance of broilers fed with diets with gradient phytase supplementation from 1 to 40 d of age.¹

Item	BW, kg/bird	BW gain, kg/bird	Feed intake, kg/bird	FCR, kg:kg2	Mortality, %3
Dietary treatment
1) Negative control (NC)4	2.848	2.805	4.166	1.486	7.0
2) NC + 500 FTU/kg5	2.881	2.837	4.232	1.492	4.2
3) NC + 1,500 FTU/kg	2.868	2.829	4.238	1.498	2.2
4) NC + 4,500 FTU/kg	2.966	2.924	4.318	1.478	4.0
5) NC + 13,500 FTU/kg	2.973	2.927	4.254	1.454	4.7
6) NC + 40,500 FTU/kg	2.956	2.914	4.239	1.455	3.1
7) Positive control (PC)	2.835	2.790	4.187	1.501	2.2
8) PC + inositol6	2.823	2.784	4.158	1.494	3.2
Pooled standard error	0.034	0.033	0.043	0.011	1.3
Source of variation	-------------------Probabilities--------------------
Log-linear effect of phytase7	0.003	0.002	0.045	0.050	0.040
Log-quadratic effect of phytase7	0.005	0.002	0.14	0.018	0.11
Treatment 1 vs. 7	0.75	0.71	0.69	0.27	0.011
Treatment 6 vs. 8	0.001	0.001	0.11	0.005	0.94
Treatment 7 vs. 8	0.76	0.86	0.56	0.60	0.58

Abbreviation: FCR, feed conversion ratio.

¹Values are least square means of 8 replicate pens, with each pen having 30 birds at placement.

²Feed conversion ratio was corrected for mortality.

³Mortality was arcsine transformed.

⁴The negative control diet was formulated to contain 0.165 and 0.150% lower calcium and phosphorus, respectively, than the positive control diet.

⁵One unit of phytase activity (FTU) is defined as the quantity of enzyme to liberate 1 μmol of inorganic phosphate per minute from 0.0051 mol/L sodium phytate at pH 5.5 and 37°C.

⁶Inositol supplementation was calculated based on the maximum inositol liberation from the diet containing the highest phytase concentration (treatment 6).

⁷Phytase levels were log₁₀ transformed before analysis. Log-linear and log-quadratic effects were analyzed for treatments 1 to 6.