T. Nakao, I. Maruyama, I. Shigeno, Y. Ando, A. Hagiwara-1997
Abstract:
The condensed cell suspension of unicellar algae Chlorella vulgaris containing vitamin B 12 in its cells has been widely used as a rotifer food in Japan. However Chlorella cells are available for rotifer culture no more than a month from the harvest although they keep in a refrigerator. We accordingly studied on the dietary value of the frozen cells of C. vulgaris for the rotifer Brachionus rotundiformis in order to lengthen the available period.
The frozen cells of C. vulgaris could not support the rotifer growth stably in a batch culture becaouse of the death of Chlorella cells by the freezing. On the contrary it supports the rotifer growth in a continuous culture, although the dietary value was inferior to that of the living cells. The dilution rate achieved at 0.3/day by the feeding of the frozen cells of C. vulgaris only (Chlorella density, 1.4 g dry weight/L diluted sea water; rotifer density, about 1200 ind./ml: culture colume, 30 L). This result can be explained by the fact that the continuous culture system reduced the elution of the content of Chlorella cells compared with batch culture, because Chlorella cells feeding into the culture were instantly fed by rotifer.
(Chlorella Industry Co. Ltd., No. 1 343; Chikugo, Fukuoka, 833, Japan)