Effects of Feeding Increasing Levels of Iron from Iron Sulfate or a Novel Source of Dietary Iron on Nursery Pig Growth Performance and Blood Parameters

A total of 140 weanling pigs (DNA 241×600, initially 5.53±0.01 kg) were used in a 32-d study evaluating the effects of feeding increasing levels of iron from either iron sulfate (FeSO4) or a micronized, agglomerated ferrous carbonate (FeCO3) on nursery pig growth performance and blood parameters. Pigs used for this trial did not receive an iron injection at birth. Pigs were weaned at approximately 21 d and were allotted to pens based on BW in a randomized complete block design. 5 pigs were placed in each pen with 4 pens per treatment. Treatments were arranged as a 2×3+1 factorial with main effects of iron source (FeSO4 vs. FeCO3) and level (10, 30, or 50 ppm) plus a control with no additional iron. The basal diet was formulated to contain 40 ppm total dietary iron based on ingredient contributions and was formulated with an iron-free trace mineral premix. Treatment diets were formulated below the pigs assumed iron requirement based on the NRC (2012). Experimental diets were fed in pellet form for the duration of the trial. The negative control was included in linear and quadratic contrast analysis. From d 0 to 32, there were no iron source×level interactions observed. Feeding increasing levels of either FeSO4 or FeCO3 improved (linear; P<0.05) ADG, G:F, Hemoglobin (Hgb), and Hematocrit (Hct) compared to the negative control. Overall, increasing dietary levels of either FeSO4 or FeCO3 improved nursey pig growth performance and blood parameters. There was no evidence of difference (P>0.05) for an iron source effect on blood parameters measured. Therefore, it can be assumed that the bioavailability of the micronized source of FeCO3 is similar to that of FeSO4.

		FeSO4, ppm			FeCO3, ppm
	Negative Control	10	30	50	10	30	50
d 0 to 321
ADG, ga	112	190	167	240	179	141	236
G:Fa	0.549	0.752	0.628	0.798	0.686	0.588	0.754
d 321
Hgb, g/dla	6.93	7.33	7.55	8.50	7.13	7.35	8.23
Hct, %a	24.8	26.6	26.9	29.8	26.0	26.5	29.5
1SEM: ADG (22.0), G:F (0.05), Hgb (0.545), and Hct (1.69) aLevel main effect (linear, P<0.05)