Preparation of single cell detritus from Laminaria saccharina as a hatchery diet for bivalve mollusks

A high-yield technique is described for the elaboration of single cell detritus (SCD) from Laminaria saccharina, based on the sequential action of C1H, enzymes (endoglucanases and cellulases) and 2 bacteria showing a high degree of cellobiotic, proteolytic, and alginolytic activity (CECT 5255 and CECT 5256). Over 85% of dried particles of L. saccharina were transformed into a suspension of free cell and bacterial and detrital particles after 24 hours of bacterial activity with this technique. These particles were less than 20 mu m in diameter, constituting a suitable diet for bivalve mollusks. After 72 hours 99% of the total particulate volume consisted of particles less than 20 mu m in diameter. Tests of hatchery diets for the seed of clam Ruditapes decussatus revealed increases of 54% and 68% for live weight and length, respectively, when SCD from L. saccharina was used as the sole dietary component compared with a live phytoplankton diet. However, SCD from L. saccharina is not a suitable food for the larvae of R. decussatus.