Induction of ovine primary myoblast proliferation by AAV-CFs-FLAG virus expressing FST protein in vitro. A, phase contrast pictures show the morphology of ovine primary myoblast cells after follistatin over-expression, as compared to negative control cells. After Giemsa staining, pictures were taken under the same magnification over a time-course of 4 days. Myoblasts were grown for 48, 72 and 96 h in growth media without or with AAV-CFs-FLAG virus transduction. Cells were fixed and stained with Giemsa. Bar =100 μM. B, absorbance (at 450 nm) was read at 48, 72 and 96 hours after plating in growth media without or with AAV-CFs-FLAG virus. Data were analyzed by one-way ANOVA (**P <0.01, n = 8).