Table 6.

Carcass characteristics of broilers fed with diets with gradient phytase supplementation from 1 to 41 d of age.¹

Item	Live weight, kg	Carcass		Breast meat		Abdominal fat
		Weight, kg	Yield, %	Weight, kg	Yield, %	Weight, g	Percentage, %
Dietary treatment
1) Negative control (NC)2	2.917	2.159	74.29	0.780	26.80	26.05	0.89
2) NC + 500 FTU/kg3	2.984	2.203	74.17	0.790	26.62	28.17	0.95
3) NC + 1,500 FTU/kg	2.953	2.211	74.91	0.795	26.90	26.51	0.89
4) NC + 4,500 FTU/kg	3.024	2.273	75.11	0.815	26.94	28.17	0.93
5) NC + 13,500 FTU/kg	3.034	2.267	74.68	0.816	26.89	27.97	0.92
6) NC + 40,500 FTU/kg	3.050	2.278	74.73	0.810	26.51	28.48	0.93
7) Positive control (PC)	2.956	2.200	74.32	0.780	26.34	27.11	0.92
8) PC + inositol4	2.923	2.174	74.32	0.784	26.79	27.57	0.94
Pooled standard error	0.030	0.024	0.33	0.011	0.23	1.02	0.03
Source of variation	--------------------Probabilities---------------------
Log-linear effect of phytase5	<0.001	<0.001	0.054	0.002	0.89	0.042	0.27
Log-quadratic effect of phytase5	<0.001	<0.001	0.053	0.004	0.83	0.11	0.36
Treatment 1 vs. 7	0.21	0.12	0.94	0.98	0.14	0.39	0.52
Treatment 6 vs. 8	<0.001	<0.001	0.23	0.037	0.35	0.44	0.79
Treatment 7 vs. 8	0.26	0.29	0.99	0.74	0.13	0.70	0.49

¹Values are least square means of 8 replicate pens, with 12 birds selected from each pen for processing.

²The negative control diet was formulated to contain 0.165 and 0.150% lower calcium and phosphorus, respectively, than the positive control diet.

³One 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.

⁴Inositol supplementation was calculated based on the maximum inositol liberation from the diet containing the highest phytase concentration (treatment 6).

⁵Phytase levels were log₁₀ transformed before analysis. Log-linear and log-quadratic effects were analyzed for treatments 1 to 6.