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

Abstract

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.

Keywords: ADFI, average daily feed intake; ADG, average daily gain; Bmi1, B cell-specific moloney murine ieukemia virus integration site 1; ChgA, chromogranin A; DM, dry matter; F/G, feed: gain ratio; Fe-Gly, ferrous glycinate; FeSO4, ferrous sulfate; Growth performance; H&E, hematoxylin and eosin; Intestinal cell proliferation; Intestinal development; Iron; Lgr5, leucine rich repeat containing G protein-coupled receptor 5; Lyz, lysozyme; Muc2, mucin 2; Olfm, olfactomedin; PCNA, proliferating cell nuclear antigen; TIBC, total iron binding capacity; TSAT, transferrin saturation; Weanling piglets; ZO-1, zonula occluden-1.