RNA interference represents one of the potential mechanisms of regulation of gene expression. Selective downregulation of myostatin (MSTN), a member of transforming growth factor- (TGF-) superfamily and a negative regulator of myogenesis, has been demonstrated to enhance skeletal muscle growth. In this study, we studied short hairpin RNA (shRNA)-induced myostatin gene silencing in chicken embryonic myoblast cells using seven different shRNA-expressing constructs by reverse transcription-quantitative real time PCR (RT-qPCR). Myostatin-silencing efficiency of all shRNA constructs were first evaluated in human embryonic kidney cell line 293T (HEK293T) cells, where we observed 3075.6% reduction in myostatin expression, followed by chicken embryo myoblast cells that revealed up to 55% reduction in myostatin expression along with upregulation of MyoD by 4.65-folds. Consistent with the earlier observations, the transfection of cells with plasmids led to significant increase in interferon responsive genes OAS1 and IFN (2112-folds), independent of myostatin silencing in both HEK293T and chicken embryonic myoblast cells. Our study suggests that apart from shRNA sequences, cell type-specific factors may play a significant role in determining the knockdown efficiency of shRNAs. (c) 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29: 425431, 2013