Moisture, protein, and amino acid contents of three freshwater zooplankton used as feed for aquacultured larvae and postlarvae

Abstract

The moisture content, crude protein level, and amino acid profile of three freshwater zooplank- ton (Moina micrura, Diaphanosoma excisum, Brachionus calyciflorus) commonly used for rear- ing fish larvae were analyzed using standard methods. The moisture contents and crude protein levels were similar, as follows: M. micrura 89% and 52.4%, D. excisum 89.3% and 57.3%, and B. calyciflorus 91.6% and 50.3%, respectively. The samples contained 17 amino acids: nine essential and eight non-essential amino acids. The dominant essential amino acids (per 16 g N) in M. micrura were lysine (10.73 g), arginine (8.17 g), leucine (8.0 g), and histidine (5.09 g); in D. excisum, lysine (9.95 g), leucine (8.0 g), valine (6.23 g), and arginine (4.78 g), and in B. caly- ciflorus, leucine (8.95 g), lysine (8.64 g), arginine (6.37 g), phenylalanine (5.20 g), and valine (4.83 g). In all three species, glutamine and aspartic acid dominated the non-essential amino acid profile, and methionine was the essential amino acid in the smallest concentration. Differences among amino acid profiles were insignificant (p>0.05).