title: An energy-rich diet causes rumen papillae proliferation associated with more IGF type 1 receptors and increased plasma IGF-1 concentrations in young goats.
abstract: We tested the hypothesis that the dietary energy-dependent alterations of the rumen papillae size are accompanied by corresponding changes in systemic insulin-like growth factor (IGF)-1 concentration and in rumen papillary IGF type 1 receptors (IGF-1R). Young male goats (n=24) were randomly allocated to two groups (n=12) and fed a high level (HL) metabolizable energy [1200 kJ/(kg(0.75).d)] or a low level (LL) [500 kJ/(kg(0.75).d)] diet for 42 d. The concentration of ruminal total SCFA did not differ between the groups, but the molar proportion of butyric acid was enhanced by 70% in the HL group (P<0.05). Both the length and width of the papillae were greater (P<0.05) in the HL group, and the surface was 50-100% larger (P<0.05) in the tissue sampled from the artrium ruminis, the ventral ruminal sac and the ventral blind sac. Transport of Na+ across the rumen epithelium, which is amiloride sensitive, was higher (P<0.05) in the HL than in the LL group. Furthermore, the plasma IGF-1 concentration was about twofold higher in the HL group (P<0.05), and the maximal rumen epithelial IGF-1R binding was also higher in the HL (P<0.05) than in the LL group. IGF-1R mRNA and IGF-1 mRNA were detected in rumen papillae; however, they were unaffected by dietary treatments. DNA synthesis and cell proliferation of cultured rumen epithelial cells were higher (P<0.05) after IGF-1 treatment (25 or 50 microg/L) compared with those in the medium without IGF-1. Thus dietary energy-dependent alterations of rumen morphology and function are accompanied by corresponding changes in systemic IGF-1 and ruminal IGF-1R.
authors.affiliation: Research Institute for the Biology of Farm Animals (FBN), Dummerstorf, Germany.
authors.forename: Zanming
authors.initials: Z
authors.lastname: Shen
authors.forename: Hans-M
authors.initials: HM
authors.lastname: Seyfert
authors.forename: Berthold
authors.initials: B
authors.lastname: Löhrke
authors.forename: Falk
authors.initials: F
authors.lastname: Schneider
authors.forename: Rudi
authors.initials: R
authors.lastname: Zitnan
authors.forename: Arthur
authors.initials: A
authors.lastname: Chudy
authors.forename: Siegfried
authors.initials: S
authors.lastname: Kuhla
authors.forename: Harald M
authors.initials: HM
authors.lastname: Hammon
authors.forename: Juerg W
authors.initials: JW
authors.lastname: Blum
authors.forename: Holger
authors.initials: H
authors.lastname: Martens
authors.forename: Hans
authors.initials: H
authors.lastname: Hagemeister
authors.forename: Juergen
authors.initials: J
authors.lastname: Voigt
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002149:Energy Intake; D006041:Goats / Q000033:anatomy & histology*; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000235:genetics; D008297:Male; D009092:Mucous Membrane / Q000033:anatomy & histology / Q000737:chemistry; D012333:RNA, Messenger / Q000032:analysis; D017526:Receptor, IGF Type 1 / Q000032:analysis* / Q000235:genetics; D012417:Rumen / Q000033:anatomy & histology* / Q000737:chemistry*
chemical_list: D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1