PRIMARY-CELL CULTURE FROM GILL EXPLANTS OF RAINBOW-TROUT

Primary cultures of gill cells were initiated from gill filament explants of rainbow trout, Oncorhynchus mykiss. The explants were cultured in Leibovitz L-15 medium with 5, 10 or 20% foetal calf serum (FCS) and L-glutamine. The attachment efficiency was serum-dependent though increased FCS concentration did not stimulate further outgrowth of cells. The explants produced cell outgrowth 24 h after attachment as a sheet of cells which exhibited characteristics of gill pavement epithelial cells as indicated by surface microridges revealed by scanning electron micrographs. There was high proliferation for the first 14 days then a stable plateau for 30 days followed by a decline phase from 45 days. Following removal of cells, the explants produced further cell outgrowth which was especially active at the proliferation phase (14 days). Removal of these cells caused the explants to produce a further proliferation of cells reaching confluence in 10-14 days. After the third cell removal cell outgrowth from explants showed migratory activity but did not develop to resemble gill epithelial cells. The use of gill explants to establish primary cultures of fish gill cells has advantages which include longevity of the culture and successive proliferations from explants which could provide a useful tool for the investigation of long-term processes in cellular biology and reduce the number of culture preparations. (C) 1995 The Fisheries Society of the British Isles.