Myogenesis-Related Gene Expression in Rainbow Trout Oncorhynchus mykiss Walb. in Response to Feeding with Commercial Feeds Differing in Composition

Gene expression levels of myogenic regulatory factors (MRFs) (myf5, myod2, and myog), myostatin (mstn1a and mstn1b), and the muscle protein myosin (myhc) in muscles were studied in the rainbow trout Oncorhynchus mykiss Walb. Study fish of three size groups (SGs) were fed with two commercial feeds differing in compositions. Expression levels of myhc, myf5, myog, and mstn1a in muscles were found to differ depending on the feed, especially in smaller fish (<1000 g). The finding suggests that the feed composition, including the quantitative ratio of ingredients and the sources of proteins, fats, and carbohydrates in the feed, affects the muscle growth regulation in early trout growth and development. The results complement the literature data on features of the regulation of myogenesis in response to external factors.