Reevaluation of the Necessity of Iron Injection to Newborn Piglets

The growth and immune responses to endotoxin lipopolysaccharide (LPS) challenge ( $20{\mu}g/kg$) of piglets with and without a iron dextran injection (Fe, 200 mg/head) two days after birth are compared. Sixty-four newborn piglets from eight litters were allocated randomly to one of four treatments. The control received no iron dextran and only saline (Sal) injection on the second and fifteenth day after birth (Sal-Sal). The remaining three groups received Fe-Sal, Sal-LPS, Fe-LPS treatments respectively. On fifteen days of age, blood samples of piglets were taken at 0 h, 1 h, 2 h and 4 d after saline or LPS injection to determine immune functions and blood characteristics. The trial terminated when the pig reached 56 days and the average daily gain of piglets was then measured. Daily gain, serum immunoglobulin G (IgG) concentration and red blood cell counts did not vary significantly among the four groups at any measuring times. Serum tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) concentration increased sharply 1 h after LPS injection. However, iron injection did not change TNF-${\alpha}$ concentration responds to LPS injection. White blood cell counts of two LPS injection groups were significantly lowered 1 h following the injection. In contrast, serum lactoferrin concentration had increased significantly 1 and 2 h postinjection. Furthermore, iron injection produced no further effects on these two criteria. Iron injection increased the hemoglobin (Hb) concentration of piglets at any measuring time, and LPS injection lowered Hb concentration. In conclusion, a 200 mg/head of iron dextran injection on the second day after birth increased Hb concentration, had no detrimental effect on the immune responses and growth of piglets. Moreover, if creep feed (175 mg Fe/kg feed) is provided from d 7 after birth, the Fe-injection does not contribute to overall performance of piglets and may not be a necessity in practice.