Effects of colostrum feeding and dexamethasone treatment on mRNA levels of insulin-like growth factors (IGF)-I and -II, IGF binding proteins-2 and -3, and on receptors for growth hormone, IGF-I, IGF-II, and insulin in the gastrointestinal tract of neonatal calves.
The somatotropic axis regulates growth of the gastrointestinal tract (GIT). In addition, colostrum feeding and glucocorticoids affect maturation of the GIT around birth in mammals. We have measured mRNA levels of members of the somatotropic axis to test the hypothesis that colostrum intake and dexamethasone treatment affect respective gene expression in the GIT. Calves were fed either colostrum or an isoenergetic milk-based formula, and in each feeding group, half of the calves were treated with dexamethasone (DEXA; 30 microg/kg body weight per day). Individual parameters of the somatotropic axis differed (P < 0.05) among different GIT sections and formula feeding increased (P < 0.05) mRNA levels of individual parameters at various sites of the GIT. Effects of DEXA on the somatotropic axis in the GIT partly depended on different feeding. In colostrum-fed calves, DEXA decreased (P < 0.05) mRNA levels of IGF-I (esophagus, fundus, duodenum, and ileum), IGF-II (fundus), IGFBP-2 (fundus), IGFBP-3 (fundus), IGF1R (esophagus, ileum, and colon), IGF2R (fundus), GHR (fundus), and InsR (esophagus, fundus), but in formula-fed calves DEXA increased mRNA levels of IGF-I (esophagus, rumen, jejunum, and colon). Furthermore, DEXA increased (P < 0.05) mRNA levels of IGF-II (pylorus), IGFBP-3 (duodenum), IGF2R (pylorus), and GHR (ileum), but decreased mRNA levels of IGFBP-2 (ileum), and IGF1R (fundus). Whereas formula feeding had stimulating effects, effects of DEXA treatment on the gene expression of parameters of the somatotropic axis varied among GIT sites and partly depended on feeding.
Ontsouka
C E
CE
Division of Animal Nutrition and Physiology, Institute of Animal Genetics, Nutrition and Housing, University of Berne, Route de la Tioleyre 4, 1725 Posieux, Switzerland.
Sauter
S N
SN
Blum
J W
JW
Hammon
H M
HM
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D002417:Cattle / Q000378:metabolism*; D003126:Colostrum / Q000502:physiology*; D003907:Dexamethasone / Q000494:pharmacology*; D004435:Eating; D041981:Gastrointestinal Tract / Q000187:drug effects / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D005938:Glucocorticoids / Q000494:pharmacology; D006133:Growth Substances / Q000235:genetics / Q000378:metabolism*; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000032:analysis / Q000187:drug effects; D017526:Receptor, IGF Type 1 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D017527:Receptor, IGF Type 2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D011972:Receptor, Insulin / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D011986:Receptors, Somatotropin / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
D005938:Glucocorticoids; D006133:Growth Substances; D018971:Insulin-Like Growth Factor Binding Protein 2; D018972:Insulin-Like Growth Factor Binding Protein 3; D012333:RNA, Messenger; D017527:Receptor, IGF Type 2; D011986:Receptors, Somatotropin; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D003907:Dexamethasone; D017526:Receptor, IGF Type 1; D011972:Receptor, Insulin