Table 3. Growth performance of Korean native ducks fed diets with two levels of crude protein and apparent metabolic energy during 0 to 21 days

		Body weight (g/bird)	BW gain (g/bird)	Feed intake (g/bird)	FCR (FI/BW gain)
Items
AME_n (kcal/kg)	Protein level (%)
2,900	21	490.82^c	445.43^c	1,260.3^b	2.85
2,900	20	564.21^ab	518.82^ab	1,498.1^a	2.90
2,800	21	613.72^a	568.34^a	1,552.2^a	2.74
2,800	20	527.79^bc	482.41^bc	1,428.2^a	2.98
SEM		23.569	23.527	51.895	0.131
AME_n (kcal/kg)
2,900		527.51	482.13	1,379.2^b	2.88
2,800		570.76	525.37	1,490.2^a	2.86
SEM		16.666	16.636	36.696	0.093
Protein level (%)
21		552.27	506.88	1,406.3	2.80
20		546.00	500.62	1,463.1	2.94
SEM¹		16.666	16.636	36.696	0.093
Probability
AME_n		0.08	0.08	0.04	0.92
Protein		0.79	0.79	0.29	0.28
AME_n×Protein		<0.01	<0.01	<0.01	0.49

Values in a row with different superscripts are significantly different (P<0.05).
Pooled standard error of the means.