title: Postprandial expression of growth-related genes in Atlantic salmon (Salmo salar L.) juveniles fasted for 1 week and fed a single meal to satiation.
abstract: We investigated postprandial changes in transcript abundance following a single satiating meal in juvenile Atlantic salmon (Salmo salar L.) (about 70 g body mass) following fasting for 1 week at 12°C. The expression of twenty-three growth-related genes was determined in fast myotomal muscle using quantitative real-time PCR at the following postprandial time points: - 12, 0, 1, 3, 6, 12, 24, 48 and 96 h. The gut was fullest 1-6 h after feeding and emptied within 48-96 h. IGF-I, MyoD1c, MRF4 and myf5 transcripts were sharply up-regulated within 1 h of refeeding and are promising candidate genes involved in a fast-response signalling system that regulates fish myotomal muscle growth. These genes clustered together with MyoD1b and suggest a coordinated regulation to favour resumption of myogenesis as an early response to feeding. Insulin-like growth factor (IGF)-II and the ubiquitin ligase MAFbx/atrogin-1 were initially down-regulated but restored to initial values after 12 h. It is also suggested that local production of IGF-I within the muscle might suppress catabolic pathways depressing MAFbx/atrogin-1.
authors.affiliation: CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental and ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Universidade de Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal. lvalente@icbas.up.pt
authors.forename: Luísa M P
authors.initials: LM
authors.lastname: Valente
authors.forename: Neil I
authors.initials: NI
authors.lastname: Bower
authors.forename: Ian A
authors.initials: IA
authors.lastname: Johnston
mesh_terms: D000818:Animals; D005215:Fasting / Q000502:physiology*; D029941:Fish Proteins / Q000235:genetics; D005502:Food; D015870:Gene Expression / Q000502:physiology*; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D024510:Muscle Development / Q000235:genetics*; D009124:Muscle Proteins / Q000235:genetics; D019518:Postprandial Period; D012333:RNA, Messenger / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D020317:Salmo salar / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D012527:Satiation; D013002:Somatomedins / Q000235:genetics; D044767:Ubiquitin-Protein Ligases / Q000235:genetics
chemical_list: D029941:Fish Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; D013002:Somatomedins; D007335:Insulin-Like Growth Factor II; D044767:Ubiquitin-Protein Ligases