Unidentified cells reside in fish skeletal muscle

Cell cultures were established from the skeletal muscle tissue of 6–13 months old rainbow trout and 12–14 months old yellow perch. Approximately 27,000 ± 5,000 cells/g (trout; N = 5) and 5,000 ± 1,200 cells/g of tissue (perch; N = 4) were obtained. Isolation and propagation were qualitatively greater for both species when the cells (younger fish producer more cells than older fish) were exposed to DMEM + 15% FBS, rather than L-15 + 15% FBS, at 20 °C (trout) and at 24 °C (yellow perch). Two morphologically distinct cell types were observed in cultures of both species, some of which eventually formed very small myotubes, which displayed immunocytological reactivity for myogenin, myosin heavy chain, and α-actinin; the second population of cells remained unstained. Successful cryopreservation was achieved using a 5% DMSO and 95% serum mixture, but post-thawing viabilities were low 5–27% (trout) and 14–30% (perch). Further research is needed in order to determine cell type specificity of isolated cells.