The pattern of gene expression (IGF family, muscle growth regulatory factors and osteogenesis related genes) involved in growth of skeletal muscle in pikeperch (Sander lucioperca) during ontogenesis

Abstract The pikeperch ( Sander lucioperca ) is an economically important freshwater fish and a valuable food with high market acceptance. It is undergoing important changes in growth and regulatory metabolism during the ontogeny. Hence, the current study aims to investigate the mRNA expression of the growth hormone ( gh )/insuline-like growth factor ( igf ) axis ( ghr, igfI, igfbp, igfr ), muscle regulatory factors ( pax7, myf5, myod, myogenin, mrf, mymk, mstn ) and osteogenesis related genes ( colla1a, fib1a, on, op, ostn ) from hatching through day 40th post hatching (DPH). The average total length (TL) of larvae measured at hatching was 3.6 ± 0.4 mm (67 degree-day) and at the end of experiment (40 DPH, 777 degree-day) was 27.1 ± 1.1 mm. The results showed three phases of gene expression in the egg, larval and juvenile stages of pikeperch ontogenesis. The expression pattern of fib1a and muscle gene myf5 showed the highest value at the egg stage. The growth hormone receptor gene ( ghr ), mymk and mstnb , raised to 1 DPH, whereas the expression of igf1rb and igf1bp5 was increased from 1 to 14 DPH. Increased expression of igfI , igfII, igf1bp4 and mrf4 was detected after 10 and 14 DPH. The myod1 expression raised at 8, 14 and 21 DPH. Differently myod2 showed only a large transient downregulation at 3 DPH and juvenile stage. The six genes igf1ra , pax7 , myogenin , col1a1a , on , and ostc were highly expressed at 21 DPH and juvenile stage. Results from this study suggest that basal metabolism, growth of body cells, muscle and bone proliferation and development can be regulated by the dynamic changes in gene expression patterns in this species. The identified genes will help to understand the basic biological process of pikeperch larvae, and development, which is very important in pikeperch farming.