title: Effect of dietary zinc oxide on morphological characteristics, mucin composition and gene expression in the colon of weaned piglets.
abstract: The trace element zinc is often used in the diet of weaned piglets, as high doses have resulted in positive effects on intestinal health. However, the majority of previous studies evaluated zinc supplementations for a short period only and focused on the small intestine. The hypothesis of the present study was that low, medium and high levels of dietary zinc (57, 164 and 2,425 mg Zn/kg from zinc oxide) would affect colonic morphology and innate host defense mechanisms across 4 weeks post-weaning. Histological examinations were conducted regarding the colonic morphology and neutral, acidic, sialylated and sulphated mucins. The mRNA expression levels of mucin (MUC) 1, 2, 13, 20, toll-like receptor (TLR) 2, 4, interleukin (IL)-1β, 8, 10, interferon-γ (IFN-γ) and transforming growth factor-β (TGF-β) were also measured. The colonic crypt area increased in an age-depending manner, and the greatest area was found with medium concentration of dietary zinc. With the high concentration of dietary zinc, the number of goblet cells containing mixed neutral-acidic mucins and total mucins increased. Sialomucin containing goblet cells increased age-dependently. The expression of MUC2 increased with age and reached the highest level at 47 days of age. The expression levels of TLR2 and 4 decreased with age. The mRNA expression of TLR4 and the pro-inflammatory cytokine IL-8 were down-regulated with high dietary zinc treatment, while piglets fed with medium dietary zinc had the highest expression. It is concluded that dietary zinc level had a clear impact on colonic morphology, mucin profiles and immunological traits in piglets after weaning. Those changes might support local defense mechanisms and affect colonic physiology and contribute to the reported reduction of post-weaning diarrhea.
authors.affiliation: Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.affiliation: Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Pieper
authors.affiliation: Institute of Veterinary Anatomy, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Rieger
authors.affiliation: Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
authors.forename: Wilfried
authors.initials: W
authors.lastname: Vahjen
authors.affiliation: Grup de Nutrició, Maneig i Benestar Animal, Departament de Ciència Animal i dels Aliment, Facultat de Veterinària, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Roger
authors.initials: R
authors.lastname: Davin
authors.affiliation: Institute of Veterinary Anatomy, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
authors.forename: Johanna
authors.initials: J
authors.lastname: Plendl
authors.affiliation: Institute of Anatomy, University of Veterinary Medicine Hannover Foundation, Hannover, Germany.
authors.forename: Wilfried
authors.initials: W
authors.lastname: Meyer
authors.affiliation: Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Zentek
mesh_terms: D000818:Animals; D003106:Colon / Q000033:anatomy & histology* / Q000187:drug effects / Q000378:metabolism*; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004032:Diet; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D020397:Goblet Cells / Q000187:drug effects / Q000378:metabolism; D009077:Mucins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013194:Staining and Labeling; D034421:Sus scrofa; D014886:Weaning; D015034:Zinc Oxide / Q000494:pharmacology*
chemical_list: D016207:Cytokines; D009077:Mucins; D012333:RNA, Messenger; D015034:Zinc Oxide