Recent advances in biological aspects of mass culture of rotifers (Brachionus plicatilis) in Japan
This paper summarizes fundamental research on improved rotifer culture technology in Japan. (1) Classification of Brachionus plicatilis strains into L- and S-types was supported by cross-mating experiments. We succeeded in crossing rotifers in each strain type belonging within L or S, but failed to obtain fertilized eggs in crosses made between L- and S-type strains. (2) Mass production of the resting eggs of L-type rotifers was conducted in 50 m'1 tanks by feeding the rotifers with baker's yeast and frozen Nannochloropsis oculata. Ten-day cultures produced about 2.3 x 109 resting eggs. The number of resting eggs produced by 1 g dry weight of food ranged from 87 to 149 x 103 eggs. (3) High-density rotifer mass culture technology is being developed by feeding condensed suspensions of freshwater Chlorella, which is commercially available (15 x 109 cells/ml, vitamin B 12 1 mg/l), to rotifers cultured in 1 m3 tanks. Two nylon filter mats (1.1 x 2 m, 1 cm thickness) washed daily, were inserted into each tank to remove solids such as rotifer faeces. The rotifer culture could supply 5.9 x 108 rotifers d -1 throughout a 40-d culture period and maintain a rotifer density of more than 1000 individuals m l-1 .
Article from Marine Science Symposia Vol. 201 - "Mass rearing of juvenile fish". Symposium held in Bergen, 21-23 June 1993. To access the remaining articles please click on the keyword "MSS Vol. 201".
