Mass Production of Resting Eggs by the Freshwater Rotifer, Brachionus calyciflorus Pallas with Exchange of Culture Water and Supplemental Aeration

This study was performed to investigate the formation and mass production of resting eggs by freshwater rotifer, Brachionus calyciflorus as influenced by different aeration supplements and exchange intervals of culture water in 15-L culture vessels and 500 L culture tanks. The maximum densities and mixis rates of the rotifers were not different between experimental group exposed to air or oxygen supplements. However, the fertilization rate and formation of resting eggs of the rotifers in the air-supplemented group were significantly higher than those in the oxygen supplemented group. In the experiment concerning exchange interval of culture water, the maximum density of the rotifers and formation of resting eggs in the batch culture were significantly higher than those in the semi-continuous culture with exchange of water every day. The formation of resting eggs per Chlorella dry weight was highest in the semi-continuous culture with exchange of water every day. The resting eggs of rotifers were produced at a density of eggs in 500-L culture tanks. In this study, the batch culture with air is an effective method for mass production of resting eggs by the freshwater rotifer, B. calyciflorus, and the efficiency of mass production of resting eggs by this rotifer was similar to that of the seawater rotifers, B. plicatilis and B. rotundiformis.