An energy-rich diet causes rumen papillae proliferation associated with more IGF type 1 receptors and increased plasma IGF-1 concentrations in young goats.
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.
Shen
Zanming
Z
Research Institute for the Biology of Farm Animals (FBN), Dummerstorf, Germany.
Seyfert
Hans-M
HM
Löhrke
Berthold
B
Schneider
Falk
F
Zitnan
Rudi
R
Chudy
Arthur
A
Kuhla
Siegfried
S
Hammon
Harald M
HM
Blum
Juerg W
JW
Martens
Holger
H
Hagemeister
Hans
H
Voigt
Juergen
J
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*
D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1