Myostatin inhibits proliferation but not differentiation of trout myoblasts

► Mstn gene expression decreases during differentiation of trout myoblasts. ► HuMSTN induces phosphorylation of Smad3 in myoblasts and myotubes. ► HuMSTN inhibits proliferation of trout myoblasts. ► HuMSTN does not inhibit differentiation of trout myoblasts. ► HuMSTN has no effect on MyoD protein level.