M. Uchida, K. Nakata, M. Maeda-1997
Journal of Applied Phycology, 9 (6): 541-549 (from Current Contents)
Abstract:
An algal suspension containing protoplasmic detritus (termed, single cell detritus (SCD)) was prepared from freeze-dried fronds of Ulva and its dietary value to Artemia nauplii was tested after size fractionation. The dissolved fraction (<0.22 mu m) of the Ulva suspension contained ca. 48% of the original protein in the Ulva, but had no dietary value to Artemia, which is a suspension feeder. In contrast, the fraction passing through a 100-mu m mesh and containing SCD of 2-14 mu m in diameter, contributed to the survival of Artemia. The fraction remaining on the 100 mu m mesh was further incubated with and without the bacterium Pseudoalteromonas espejiana strain AR06 FERM BP-5024. The bacterium degraded Ulva forming new SCD over 10(6) mL(-1) level as rapidly as by 16 h of incubation. The dietary value of Ulva for Artemia growth was elevated over four times by the incubation. The protein content of the SCD was approximately doubled by the attaching of bacteria, suggesting the enhanced Artemia growth is attributable to the combined effect of the SCD and the bacteria. Development of a hatchery diet from Ulva, a resource with a low commercial value, is suggested utilizing the degrading and attaching ability of P. espejiana.
(Natl. Res. Inst. Fisheries Sci., Kanazawa KU, Yokohama, Kanagawa 236, Japan)