Table 3. Effects of dietary energy and lysine levels on physiological changes, feed intake, and WEI in primiparous sows

Item1)	ME 3,265 kcal/kg				ME 3,365 kcal/kg				SEM	p-value
	Lys	Lys	Lys	Lys	Lys	Lys	Lys	Lys		E	L	I
	0.55	0.65	0.75	0.85	0.55	0.65	0.75	0.85
	0.70	0.85	1.00	1.15	0.70	0.85	1.00	1.15
	%	%	%	%	%	%	%	%
Body weight (kg)
35 d	167.9	167.0	167.8	168.8	169.1	168.1	167.9	162.5	9.91	0.74	0.91	0.77
110 d	199.0	196.0	192.6	190.6	200.6	194.8	196.0	202.2	13.15	0.36	0.79	0.72
BW gain (35–110 d)	31.1	29.0	24.8	21.8	31.5	26.7	28.1	39.7	10.61	0.07	0.56	0.25
24 hrs postpartum	179.5	183.7	167.2	168.2	172.9	173.0	174.7	181.1	12.39	0.85	0.69	0.16
Day 21 of lactation	163.4	177.8	155.1	165.0	168.9	173.3	183.9	178.5	16.06	0.09	0.75	0.36
BW loss (0–21 d)	–16.1	–5.9	–12.1	–3.2	–4.0	0.3	9.2	–2.6	12.65	0.05	0.57	0.51
Backfat thickness (mm)
35 d	24.9	24.5	25.1	23.7	23.7	25.6	27.1	23.2	4.72	0.80	0.64	0.86
110 d	23.9	25.8	24.1	24.2	28.2	26.2	26.8	26.2	4.26	0.10	0.96	0.80
BF gain (35–110 d)	–1.0	1.3	–1.0	0.5	4.5	0.6	–0.3	3.0	4.79	0.21	0.64	0.54
24 hrs postpartum	22.6	24.5	23.8	25.0	27.7	26.5	25.9	26.7	3.99	0.04	0.95	0.76
Day 21 of lactation	19.2	20.6	19.3	20.6	23.1	21.4	21.8	23.5	4.17	0.07	0.88	0.88
BF loss (0–21 d)	–3.4	–3.9	–4.5	–4.4	–4.6	–5.1	–4.1	–3.2	2.87	0.81	0.96	0.76
Lactational feed intake (kg/d)	4.81	5.45	5.21	4.91	5.18	5.19	5.21	4.42	0.868	0.74	0.39	0.71
WEI (d)	5.20	5.33	5.25	5.33	4.50	6.75	4.33	5.00	0.811	0.70	0.03	0.06

Factors: energy level (3,265 or 3,365 kcal of ME/kg) and lysine level (total lysine 0.55/0.70%, 0.65/0.85%, 0.75/1.00%, 0.85/1.15%) in gestation/lactation diet.
WEI, weaning-to-estrus interval; ME, metabolizable energy; Lys, lysine; SEM, standard error of the mean; E, energy effect. L, lysine effect. I, interaction between energy and lysine effects.