Effects of different iron sources on growth performance, intestinal morphology, development, and cell proliferation in weanling piglets.

The current study aimed to investigate the effects of different iron sources on growth performance and small intestinal health in weaned piglets. Two hundred and forty piglets (Duroc × Large White × Landrace, 9.52 ± 1.60 kg, 40 ± 2 d) were assigned to four treatments including control group, a basal diet without iron supplemented in mineral premix; ferrous sulfate (FeSO4) group, 100 mg Fe/kg dry matter (DM); ferrous glycinate (Fe-Gly) group, 80 mg Fe/kg DM; amino acid-Fe(II)-chelator complexes group, 30 mg Fe/kg DM. There were four pens for each treatment, and each pen had fifteen piglets. The experiment lasted for 28 days. Compared to the control group, three iron sources increased average daily feed intake (P < 0.05). Fe-Gly and amino acid-Fe(II)-chelator complexes increased average daily gain (P < 0.05). Amino acid-Fe(II)-chelator complexes increased villus height in jejunum (P < 0.05). In addition, Fe-Gly increased Ki67 and leucine rich repeat containing G protein-coupled receptor 5 (Lgr5) mRNA expression in duodenum (P < 0.05). Amino acid-Fe(II)-chelator complexes increased claudin-1 mRNA expression, and both amino acid-Fe(II)-chelator complexes and Fe-Gly increased Lgr5 mRNA expression (P < 0.05) in jejunum. These results suggest that organic iron is more effective than FeSO4 in improving growth performance, and has a positive effect on intestinal health in weanling piglets.