The Zebrafish Science Monitor Vol 3(4)
TETRAHYMENA: AN EASY ALTERNATIVE FOR PARAMECIABy J.E. Speksnijder and E. Bijmolt, Department of Genetics, Center for Biological Sciences, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands
We now routinely use Tetrahymena cultures as an alternative for Paramecia to feed the smallest baby fish. Tetrahymena have two advantages, namely that the culture medium contains few components and is easy to prepare, and that sterile cultures are commercially available from the Culture Collection of Algae and Protozoa, Freshwater Biological Association, The Ferry House, Ambleside, Cumbria LA22 0LP, UK; phone 44-5394-42468. The strain we use is Tetrahymena pyriformis (catalogue no. CCAP 1630/1W), and the PPY culture medium is prepared as follows: Dissolve 20 g proteose peptone and 2.5 g yeast extract in 1000 ml of distilled water, and sterilize in batches of 200 ml in 500 ml bottles. To start the culture, inocculate about 6 ml of dense culture in 200 ml fresh PPY medium, and grow for 3-4 days at room temperature with bottle caps opened one turn. These cultures can then be harvested, or kept for up to several weeks at 15C to start new cultures. To harvest, centrifuge the cultures for about 3 min at 500g, and rinse with PJ salt solution (see below). Repeat twice to remove all PPY medium. Add a small volume of PPY after the last step; the culture can now be used to feed the baby fish. Using Tetrahymena, we have been able to grow babyfish with survival rates comparable to those obtained with Paramecia.
PJ (Prescotts & James's) solution:
Make up the following three stock solutions, each in 100 ml distilled water:
1) 0.433 g CaCl2.2H2O and 0.162 g KCl
2) 0.512 g K2HPO4
3) 0.280 g MgSO4.7H2O
Add 1 ml of each stock solution to 1 liter distilled water.
Zebrafish Science Monitor Vol 3(4)
Return to Contents