The Culture of the Rotifer Brachionus plicatilis with Chlorella vulgaris Containing Vitamin B12in its Cells

The rotifer Brachionus plicatilis requires vitamin B12. Freshwater Chlorella, which is produced by traditional culture, cannot support rotifer growth under bacteria-free conditions. However, Chlorella enriched with vitamin B12 can support rotifer growth. To attain stable mass production of Brachionus, it is desirable to develop a food that can completely support growth of the rotifers. The authors cultured rotifers at experimental and mass culture scale with concentrated Chlorella vulgaris suspension enriched with vitamin B12 in their cells. Chlorella suspensions were prepared containing different amounts of vitamin B12 in their cells, and rotifers were then cultured in 20 ml of the prepared suspensions. The highest rotifer yield was obtained from the group cultured with Chlorella containing more vitamin B12 in their cells. The suitable content of vitamin B12 in the concentrated Chlorella suspension commercially available for mass culture of the rotifer is considered to be 200 μg per 100 g dry matter of Chlorella. The amount of vitamin B12 necessary to produce one individual rotifer is calculated at 0.32 pg. The authors conducted mass production of the rotifer with baker's yeast and refrigerated concentrated Chlorella containing vitamin B12 Rotifer culture with vitamin B12 was more stable and showed 1.3 times higher production than with normal Chlorella.