5. General Culture Procedures
5.2 Upscaling of Stock Cultures to Starter Cultures
The upscaling of rotifers is done in static systems consisting of erlemeyers of 500 ml placed at 2 cm from fluorescent light tubes (5000 lux). The temperature in the erlemeyers should not be more than 30°C. The rotifers are stocked at a density of 50 individuals.ml-1 and fed 400 ml freshly-harvested algae (Chlorella 1.6.106 cells.ml-1); approximately 50 ml of algae are added every day to supply enough food. Within 3 days the rotifer concentration can increase to 200 rotifers.ml-1 (Fig. 3.5.). During this short rearing period no aeration is applied.
Once the rotifers have reached a density of 200-300 individuals.ml-1 they are rinsed on a double submerged filter. The upper mesh size (200 mm) retains large waste particles, while the lower sieve (50 mm) collects the rotifers. If only single strainers are available this handling is done with two separate filters. If the rinsing is done under water the rotifers will not clog and losses will be limited to less than 1%.
The concentrated rotifers are then distributed in several 15 l bottles filled with 2 l water at a density of 50 individuals.ml-1. A mild tube aeration is provided. In order to avoid contamination with ciliates the air should be filtered by cartridge or activated carbon filters. Fresh algae (Chlorella 1.6.106 cells.ml-1) are supplied daily. Every other day the cultures are cleaned (double-screen filtration) and restocked at densities of 200 rotifers.ml-1. After adding algae for approximately one week the 15 l bottles are completely full and the cultures can be used for inoculation of mass cultures.
1.
Introduction
2. Morphology
3. Biology and Life History
4. Strain Differences
5. General Culture Procedures