Table 3. Growth performance of White Pekin ducks from 1 to 21 days of age fed diets containing different dietary standardized ileal digestible lysine concentrations¹⁾

Item	Standardized ileal digestible lysine concentrations (%)						SEM²⁾	p-value	Polynomial contrast³⁾
Item	0.72	0.80	0.88	0.96	1.04	1.12	SEM²⁾	p-value	Lin	Quad
BW (g)
Day 1	52.73	53.11	53.03	53.47	53.04	52.91	0.201	0.937	0.778	0.639
Day 7	173.92^a	174.05^a	174.56^a	189.25^b	189.31^b	182.69^ab	1.049	< 0.001	< 0.001	< 0.001
Day 14	494.42^ab	474.06^a	540.58^bc	573.17^c	580.56^c	549.72^c	4.532	< 0.001	< 0.001	< 0.001
Day 21	1,039.75^ab	1,021.06^a	1,106.34^bc	1,168.49^c	1,180.88^c	1,170.50^c	7.616	< 0.001	< 0.001	< 0.001
ADG (g/bird/d)
Day 7	17.31^a	17.28^a	17.36^a	19.40^b	19.47^b	18.54^ab	0.148	< 0.001	< 0.001	< 0.001
Day 14	45.79^ab	42.86^a	52.29^bc	54.29^c	55.89^c	52.43^bc	0.656	< 0.001	< 0.001	< 0.001
Day 21	77.90^a	78.14^a	80.82^ab	85.05^ab	85.76^ab	88.68^b	0.856	0.002	< 0.001	< 0.001
Day 1–21	47.00^ab	46.09^a	50.16^bc	53.10^c	53.71^c	53.22^c	0.357	< 0.001	< 0.001	< 0.001
ADFI (g/bird/d)
Day 7	26.78	26.56	26.51	26.73	26.64	26.47	0.045	0.304	0.244	0.510
Day 14	79.06	75.08	78.03	77.32	74.65	77.76	0.634	0.299	0.525	0.553
Day 21	141.14	134.54	134.47	137.72	134.51	137.72	1.161	0.493	0.561	0.318
Day 1–21	82.33	78.73	79.67	80.59	78.60	80.65	0.521	0.323	0.473	0.295
FCR (g/g)
Day 7	1.55^b	1.54^b	1.53^b	1.39^a	1.37^a	1.43^ab	0.011	< 0.001	< 0.001	< 0.001
Day 14	1.74^b	1.76^b	1.50^a	1.41^a	1.34^a	1.50^a	0.018	< 0.001	< 0.001	< 0.001
Day 21	1.82^b	1.73^ab	1.68^ab	1.62^ab	1.59^ab	1.55^a	0.023	0.021	< 0.001	0.001
Day 1–21	1.76^c	1.71^bc	1.59^ab	1.52^a	1.47^a	1.52^a	0.014	< 0.001	< 0.001	< 0.001

Values are the mean of eight replicates per treatment.
Pooled standard error of the mean.
Orthogonal polynomial contrast coefficients were used to determine linear (Lin) and quadratic (Quad) effects of increasing digestible lysine.
Values in a row with different superscripts differ significantly (p < 0.05).
BW, body weight; ADG, average daily gain; ADFI, average daily feed intake; FCR, feed conversion ratio.