title: Effect of dexamethasone on hypothalamic expression of appetite-related genes in chickens under different diet and feeding conditions.
abstract: BACKGROUND
  Glucocorticoids (GCs) are involved in the control of appetite in birds and mammals. The effect of GCs on feed intake in birds depends on their dietary energy level. But the regulation mechanism of GCs on appetite is still unclear in chickens facing to different energy level. An experiment was conducted to investigate the effect of dexamethasone (DEX) on hypothalamic expression of appetite-related peptides in chickens fed high/low fat diet and under fasting/feeding condition.
  
  
  RESULTS
  An interaction between DEX injection and dietary energy level was found on hypothalamic corticotropin-releasing hormone (CRH) gene expression in fasted chickens (P < 0.05). The chickens, given a DEX injection and a low fat diet treatment, had the highest CRH mRNA levels than any of the fasted chickens given treatments (P < 0.05). Under fasting conditions, the DEX treatment significantly increased hypothalamic neuropeptide Y (NPY) and GC receptors mRNA levels (P < 0.05). Under re-feeding conditions, DEX treatment significantly decreased hypothalamic expression levels of NPY and agouti-related peptide (AgRP) but significantly increased the level of hypothalamic CRH expression (P < 0.05).
  
  
  CONCLUSIONS
  A regulatory network formed by NPY, AgRP and CRH is associated with the appetite-control by GCs. The result suggests that the regulation of GCs on orexigenic neuropeptides expression is dependent at least partially on dietary energy level and feeding state.
authors.affiliation: Department of Animal Science, Shandong Agricultural University, Shandong Key Lab for Animal Biotechnology and Disease Control, Taian, Shandong 271018 China.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Animal Science, Shandong Agricultural University, Shandong Key Lab for Animal Biotechnology and Disease Control, Taian, Shandong 271018 China.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Xu
authors.affiliation: Department of Animal Science, Shandong Agricultural University, Shandong Key Lab for Animal Biotechnology and Disease Control, Taian, Shandong 271018 China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Animal Science, Shandong Agricultural University, Shandong Key Lab for Animal Biotechnology and Disease Control, Taian, Shandong 271018 China.
authors.forename: Hongchao
authors.initials: H
authors.lastname: Jiao
authors.affiliation: Department of Animal Science, Shandong Agricultural University, Shandong Key Lab for Animal Biotechnology and Disease Control, Taian, Shandong 271018 China.
authors.forename: Jingpeng
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Animal Science, Shandong Agricultural University, Shandong Key Lab for Animal Biotechnology and Disease Control, Taian, Shandong 271018 China.
authors.forename: Hai
authors.initials: H
authors.lastname: Lin
keywords: Chickens; Glucocorticoids; Hypothalamus; Neuropeptides