Vitrification of caudal fin explants from zebrafish adult specimens

No data on vitrification of tissue samples are available in fishes. Three vitrification solutions were compared: VI: 20% ethylene glycol and 20% dimethyl sulphoxide; V2: 25% propylene glycol and 20% dimethyl sulphoxide, and; V3: 20% propylene glycol and 13% methanol, all three prepared in Hanks' buffered salt solution plus 20% FBS, following the same one step vitrification procedure developed in mammals. Caudal fin tissue pieces were vitrified into 0.25 ml plastic straws in 30s and stored in liquid nitrogen for 3 days minimum, warmed (10s in nitrogen vapour and 5s in a 25 degrees C water bath) and cultured (L-15 plus 20% FBS at 28.5 degrees C). At the third day of culture, both attachment and outgrowing rates were recorded. V3 led to the worst results (8% of attachment rate). VI and V2 allow higher attachment rates (VI: 63% vs V2: 50%. P < 0.05) but not significantly different outgrowing rates (83%-94%). Vitrification of caudal fin pieces is advantageous in fish biodiversity conservation, particularly in the wild, due to the simplicity of procedure and equipment.