A novel culture system for the ultra-high-density production of the rotifer, Brachionus rotundiformis—a preliminary report

Abstract

A novel culture system for continuous filtration of culture water was developed for ultra-high-density production of a marine rotifer. This ultra-high-density culture system is equipped with a membrane filtration unit (pore size: 0.4 μm) set inside a culture vessel. The culture performance of this system was tested by feeding freshwater Chlorella paste as feed in a 4-day batch culture. To prevent the membrane surface from fouling, the filtration unit was cleaned every day by dipping it in a NaOCl solution. The membrane filter unit was effective in exchanging the culture water with a high level of ammonia with fresh seawater, while rotifers and Chlorella cells were retained in the vessel. Using this membrane filtration unit with the supply of oxygen gas, a rotifer density of more than 1.6×10 5 individuals ml −1 was obtained on the 4th day of culture. The removal of accumulated ammonia from the culture water enabled an increase of the productivity and of the vitality of the rotifers.