Postprandial expression of growth-related genes in Atlantic salmon ( Salmo salar L.) juveniles fasted for 1 week and fed a single meal to satiation

• Published in: British Journal of Nutrition
• Main Authors: Valente, Luísa M. P., Bower, Neil I., Johnston, Ian A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2012
• Subjects: Nutrition and Dietetics; Medicine (miscellaneous); Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1017/s0007114512000396; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0007114512000396

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.