Table 2. Comparison of growth performance of six different energy level from hatch to day 21

Period	Diets¹⁾
Period	3200	3100	3000	2900	2800	2700	SEM	p-value
Bodyweight
Initial	48.48	48.46	48.42	48.48	48.50	48.48	0.089	0.955
Day 7	221.63	211.15	204.93	201.94	201.90	205.32	12.511	0.609
Day 14	716.89	678.50	654.80	657.25	637.60	625.53	35.473	0.190
Day 21	1,387.29^c	1,360.06^bc	1,341.76^abc	1,246.99^abc	1,239.50^ab	1,209.65^a	45.663	0.004
Average daily gain
Day 1–7	24.74	23.24	22.36	21.92	21.91	22.41	1.788	0.610
Day 8–14	70.75	66.76	64.27	65.04	62.24	60.03	3.724	0.130
Day 15–21	88.63	90.22	90.99	84.25	85.99	83.45	5.093	0.584
Day 1–21	63.75^c	62.46^bc	61.59^abc	57.07^abc	56.71^ab	55.29^a	2.175	0.004
Average daily feed intake
Day 1–7	31.47	30.14	29.29	28.71	30.07	31.06	2.310	0.840
Day 8–14	100.18	94.66	97.01	96.60	90.81	95.92	5.311	0.649
Day 15–21	130.55^b	133.34^ab	137.60^b	132.79^a	136.38^ab	132.79^ab	4.724	0.019
Day 1–21	90.91	89.57	91.57	86.03	85.75	86.59^ab	3.032	0.205
Feed conversion ratio
Day 1–7	1.27^a	1.30^b	1.31^b	1.31^b	1.37^c	1.39^d	0.004	0.001
Day 8–14	1.41^a	1.42^a	1.51^ab	1.48^ab	1.46^ab	1.60^b	0.050	0.015
Day 15–21	1.48	1.48	1.51	1.59	1.59	1.59	0.052	0.077
Day 1–21	1.43^a	1.44^a	1.49^ab	1.51^ab	1.51^b	1.57^b	0.037	0.012

Teatment number indicates dietary AME (kcal/kg).
Values in a row with different superscripts differ significantly (p < 0.05).
AME, apparent metabolizable energy.