Table 1.

Composition and nutrient levels of the diets.

Ingredient (%)	Group 1	Group 2	Group 3	Group 4	Group 5	Group 6
Corn	65.00	65.00	65.00	65.00	65.00	65.00
Soybean meal	15.57	15.57	15.57	15.57	15.57	15.57
Soybean oil	0.50	0.50	0.50	0.50	0.50	0.50
Compound Amino Acids 1	0.23	0.23	0.23	0.23	0.23	0.23
Premix 2	8.71	8.71	8.71	8.71	8.71	8.71
Ground rice hulls	0.00	2.08	4.18	6.29	7.31	8.37
Calcium hydrophosphate	4.05	3.11	2.16	1.20	0.74	0.26
Stone powder	5.94	4.80	3.65	2.50	1.94	1.36
Total	100.00	100.00	100.00	100.00	100.00	100.00
Calculated Level 3
ME MJ/kg	11.15	11.15	11.15	11.15	11.15	11.15
CP %	13.00	13.00	13.00	13.00	13.00	13.00
Methionine %	0.21	0.21	0.21	0.21	0.21	0.21
Lysine %	0.75	0.75	0.75	0.75	0.75	0.75
Ca %	3.00	2.40	1.80	1.20	0.90	0.60
Total P %	0.98	0.82	0.66	0.50	0.42	0.34
Available P %	0.81	0.65	0.49	0.32	0.24	0.16
Analyzed Level 4
Total E MJ/kg	10.98 ± 0.17	11.17 ± 0.27	11.07 ± 0.16	10.97 ± 0.20	11.04 ± 0.08	11.06 ± 0.20
CP %	12.89 ± 0.22	12.85 ± 0.24	12.79 ± 0.32	12.81 ± 0.40	12.82 ± 0.16	12.81 ± 0.23
Ca %	2.97 ± 0.13	2.36 ± 0.06	1.76 ± 0.12	1.14 ± 0.08	0.87 ± 0.12	0.58 ± 0.07
Total P %	0.93 ± 0.04	0.78 ± 0.05	0.62 ± 0.05	0.48 ± 0.03	0.40 ± 0.02	0.31 ± 0.02

¹ Compound Amino Acids provided the following: methionine, lysine, tryptophan and threonine. ² Premix provided the following: decavitamin, complex minerals, baking soda, choline chloride, salt, secondary powder, bentonite, et al. ³ Values were calculated from data provided by Feed Database in China (2010). ⁴ Values were presented as the means of triplicate per sample.