title: Dietary Iron Deficiency and Oversupplementation Increase Intestinal Permeability, Ion Transport, and Inflammation in Pigs.
abstract: Understanding the influence of dietary iron deficiency and dietary iron oversupplementation on intestinal health is important for both animal production and human health.
  
  
  
  The aim of this study was to determine whether dietary iron concentration influences intestinal physiology, morphology, and inflammation in the porcine duodenum.
  
  
  
  Twenty-four male pigs (21 d old) were fed diets containing either 20 mg Fe/kg [low dietary iron (L-Fe)], 120 mg Fe/kg [adequate dietary iron (A-Fe); control], or 520 mg Fe/kg [high dietary iron (H-Fe)] by FeSO4 supplement (dry matter basis). After 32-36 d, the duodenum was harvested from pigs and mounted in Ussing chambers for the measurement of transepithelial electrical resistance (TER), short-circuit current, and (3)H-mannitol permeability. Intestinal morphology and inflammation were assessed by histologic examination, and proinflammatory gene expression was assessed by real-time polymerase chain reaction.
  
  
  
  Compared with A-Fe-fed pigs, pigs fed L-Fe diets exhibited reduced TER (by 30%; P < 0.05). Compared with that of A-Fe-fed controls, the paracellular flux of (3)H-mannitol across the duodenal mucosa was higher (P < 0.05) in L-Fe-fed (>100%) and H-Fe-fed (∼4-fold) pigs; the L-Fe-fed and H-Fe-fed groups did not differ significantly from one another. Compared with the L-Fe-fed pigs, the A-Fe-fed and H-Fe-fed pigs had malondialdehyde concentrations 1.4- and 2.5-fold higher in the duodenum and 4.4- and 6.6-fold higher in the liver, respectively (P < 0.05). Neutrophil counts were higher in both the L-Fe-fed (by 3-fold) and H-Fe-fed (by 3.3-fold) groups than in the A-Fe-fed group; the L-Fe-fed and H-Fe-fed groups did not significantly differ from one another. Duodenal mucosal tumor necrosis factor α (TNFA), interleukin (IL) 1β, and IL6 relative gene expression was upregulated by 36%, 28%, and 45%, respectively, in H-Fe pigs (P < 0.05), but not in L-Fe pigs, compared with A-Fe pigs.
  
  
  
  These data suggest that adequate but not oversupplementation of dietary iron in pigs is required to maintain intestinal barrier health and function.
authors.affiliation: Gastrointestinal Stress Biology Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI;
authors.forename: Yihang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Animal Science, Iowa State University, Ames, IA; and.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Hansen
authors.affiliation: Department of Population Health and Pathobiology, College of Veterinary Medicine, and.
authors.forename: Luke B
authors.initials: LB
authors.lastname: Borst
authors.affiliation: Department of Animal Science, North Carolina State University, Raleigh, NC.
authors.forename: Jerry W
authors.initials: JW
authors.lastname: Spears
authors.affiliation: Gastrointestinal Stress Biology Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI; moeserad@cvm.msu.edu.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Moeser
mesh_terms: D000818:Animals; D001692:Biological Transport; D004032:Diet; D019587:Dietary Supplements; D004386:Duodenum; D007249:Inflammation / Q000209:etiology* / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D015848:Interleukin-5 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000503:physiopathology*; D007477:Ions / Q000378:metabolism*; D007501:Iron / Q000008:administration & dosage* / Q000378:metabolism; D000090463:Iron Deficiencies; D019266:Iron, Dietary / Q000008:administration & dosage* / Q000378:metabolism; D008099:Liver; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism; D009752:Nutritional Status; D044343:Overnutrition; D010539:Permeability; D013552:Swine; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D053583:Interleukin-1beta; D015848:Interleukin-5; D007477:Ions; D019266:Iron, Dietary; D014409:Tumor Necrosis Factor-alpha; D008315:Malondialdehyde; D007501:Iron
keywords: inflammation; intestinal barrier function; intestinal physiology; iron; porcine