Expression of Muscle-Specific Genes in Aquacultured Atlantic Salmon (Salmo salar L.) Fingerlings under Conditions of Different Lighting and Feeding Regimes

Gene expression levels of the myosin heavy chain (myhc) and myosin light chain 2 (mlc2), myogenic regulatory transcriptionfactors (myf5, myog, and myod1 paralogs),myostatin paralogs, and insulin-like growth factors 1 and 2 (igf1 and igf2)were studied in the muscles of salmon fingerlings farmed under differentlighting and feeding conditions at a constant water temperaturein the Republic of North Ossetia-Alania (Russian Federation). Thecombined effect of different lighting and feeding regimes affected myhc, mlc2, myod1a, myf5, myod1b, and myod1c geneexpression. The individuals reared under constant lighting conditionswere distinguished by higher expression levels of myf5, myhc and mlc2 genes compared to fish rearedunder natural light, which also corresponded to their higher growth rates.The expression levels of IGF genes varied in different ways throughoutthe experiment: igf1 gene expressionconstantly increased, while igf2 geneexpression increased during the first month of a study and decreasedthereafter. The results indicate differences in the processes ofmyogenesis regulation depending on lighting and feeding conditions.