Effect of different concentrations of dried algae (powdered chlorella) and fresh algae Nannochloropsis oculata on body and egg size of marine rotifer Brachionus plicatilis

In recent years the use of rotifers as live food for rearing fish larvae and crustacean is very important. In this study, the effect of two concentrations (2.5×106, and 5×106 cell/ml-1) of two algae (powdered chlorella and nannochloropsis), on body and egg size of marine rotifer, Brachionus plicatilis were investigated. Rotifers were cultured in standard conditions in 500 ml plastic containers. The initial density of rotifers in different treatments was 30 ind/ml. The sampling of rotifers were conducted in the exponential phase of population growth. Based on the results, no significant difference was observed in the in the size of rotifers fed at low concentration (2.5×106 cell/ml-1) of two algae (p>0.05). But rotifer body size was high at those fed low concentrations of powdered Chlorella in compare to the high concentration. Egg size in group fed powdered chlorella was more than another group. Significant differences was observed in egg size of two groups that fed on high and low density of both algae (p