Table 12. Study D: results comparing different iron sources fed to weaned piglets from weaning for 42 days.

Parameter	T1 Control	T2 Fe (II) sulphate, 85 mg Fe/kg feed	T3 Fe (III) oxide, 85 mg Fe/kg feed	T4 Ferric citrate, 85 mg Fe/kg feed	T5 Ferric citrate + Fe (II) sulphate, 170 mg Fe/kg feed	SEM	P-value
Performance parameters
Mean age at weaning (d)	24.77	24.69	24.66	24.77	24.74
N° replicate pens post-weaning	07	07	07	07	07
N° piglets per pen at weaning	05	05	05	05	05
Mean BW at weaning (kg)	6.16	6.16	6.13	6.17	6.16	0.049	1.000
Mean BW at 14 d post-weaning (kg)	7.86	8.04	8.07	8.34	8.31	0.061	0.218
Mean BW at 42 d post-weaning (kg)	22.73a	23.31ab	23.45b	24.26c	24.22c	0.103	<0.001
ADG 1–14 d post-weaning (g)	121a	134ab	137ab	156b	153b	2.975	0.004
ADG 15–42 d post-weaning (g)	531a	545ab	549ab	569b	568b	3.498	0.004
ADG 1–42 d post-weaning (g)	394a	408ab	412abc	431c	430c	2.646	<0.001
ADFI 1–14 d post-weaning (g)	152	164	160	174	171	3.296	0.460
ADFI 15–42 d post-weaning (g)	794	793	794	798	795	4.746	0.998
ADFI 1–42 d post-weaning (g)	580	583	583	590	587	3.351	0.966
FCR 1–14 days post-weaning (feed:gain)	1.252x	1.219xy	1.175xy	1.122y	1.114y	0.015	0.061
FCR 15–42 d post-weaning (feed:gain)	1.497a	1.453ab	1.446ab	1.403b	1.399b	0.008	<0.001
FCR 1–42 d post-weaning (feed:gain)	1.471c	1.428bc	1.415abc	1.369ab	1.365a	0.010	<0.001
Faecal digestibility of iron on day 42
Mean faecal dry matter (%)	36.32	37.52	36.20	39.31	39.10	0.444	0.147
Mean apparent total-tract digestibility of ash (%)	45.04a	51.92b	53.82b	51.47b	52.61b	0.659	<0.001
Mean apparent total-tract digestibility of iron (%)	10.05a	12.59ab	13.69ab	19.77c	17.17bc	0.781	<0.001
Iron content in blood serum on day 0 and 42
Iron content d 25 of age (mg/l))	0.99	0.97	0.98	0.96	0.98	0.017	0.999
Iron content d 66 of age (mg/l)	1.09	1.13	1.14	1.16	1.16	0.010	0.246

Notes:

Values are least square means of 5 piglets/pen.

SEM, Standard Error of the Mean; BW, body weight; ADG, average daily weight gain; ADFI, average daily feed intake; FCR, feed conversion ratio.

Different superscripts in same row are significant or trending (a/b/c: P ≤ 0.05; x/y 0.05 < P ≤ 0.10).

P-values in bold are P ≤ 0.05.