Effects of feed restriction on the expression profiles of the glucose and fatty acid metabolism-related genes in rainbow trout Oncorhynchus mykiss muscle

Gene expression in the muscle of rainbow trout Oncorhynchus mykiss fed either ad libitum once a week (RF, restricted feed group) or ad libitum twice per day (control) was compared to identify those genes differently regulated during restricted feeding. After 1 month, the increase in the size of the RF fish was significantly less than that of the control fish. A microarray analysis of 37,394 unique sequences revealed that 2,701 transcripts differed by more than twofold between the control and RF groups. In the RF group, one and three genes involved in fatty acid beta-oxidation were down- and up-regulated, respectively, and five glycolysis-related genes were down-regulated. The genes for growth hormone receptors-1 and -2 were up-regulated in the RF group. A number of adipocyte-related and adiponectin genes were down-regulated in the RF group, suggesting that lipid accumulation might be suppressed in this group. These results suggest that adiponectin and growth hormone signaling plays an active role in the control of energy metabolism during restricted food intake.