Table 4. Effects of vitamin supplementation levels in gestation diets on growth performance of sows during lactation

	Treatment¹⁾				SEM	p-value
	V1	V3	V6	V9	SEM	Lin.	Quad.
Body weight (kg)
24 hours postpartum	246.99	247.81	245.65	243.01	4.252	0.735	0.847
21 day of lactation	241.67	235.40	237.32	223.46	4.221	0.194	0.660
BW changes (0-21 d)	−5.32	−12.41	−10.91	−19.55	1.909	0.027	0.570
Backfat thickness (mm)
24 hours postpartum	20.33	21.27	23.35	20.33	1.161	0.830	0.375
21 day of lactation	19.11	21.91	20.32	20.33	0.946	0.739	0.653
24 hours postpartum	−1.22	−0.64	−3.03	−0.00	0.503	0.881	0.197
ADFI (kg)	5.05	4.90	4.87	4.21	0.143	0.060	0.375
WEI (day)	4.81	5.89	5.07	4.67	0.189	0.447	0.047

Treatment: V1, corn-soybean meal (SBM) based diet with 1× National Research Council (NRC, 2012) vitamin requirement; V3, corn-SBM-based diet with 3× NRC (2012) vitamin requirement; V6, corn-SBM-based diet with 6× NRC (2012) vitamin requirement; V9, corn-SBM-based diet with 9× NRC (2012) vitamin requirement.
Lin., linear; Quad., quadratic; BW, body weight; ADFI, average daily feed intake; WEI, weaning to estrus interval.