Acipenser persicus is the most important sturgeon species in the south Caspian Sea region, showing high mortality during larval culture. The aim of this study was to use the freshwater rotifer, Brachionus calyciflorus to feed A. persicus larvae to improve survival rates and enhance resistance in these larvae at the onset of exogenous feeding. Three experimental groups were used in this study; Control group similar to the feeding protocol of the hatchery was initially fed decapsulated cysts of Artemia and then fed daphnia, group 1 was fed a mixed diet of decapsulated Artemia cysts, daphnia and freshwater rotifers, group 2 was fed only on freshwater rotifers, and group 3 was fed freshwater rotifers enriched with vitamin C (ascorbic acid 6- palmitate). A total of 45 larvae were stocked in each experimental tank (100 l capacity) filled with 30 l of water. Three replicates were used for each experimental group. Larvae were fed four times a day at the rate of 30% of body weight per day for 8 days. Mean dissolved oxygen, pH and water temperature throughout the experimental period were 9.58±0.2 mg/l, 8.5±0.1 and 22.5±0.5 ºC, respectively. DNA sequence of genome DNA extracted from the native freshwater rotifer under study was determined and registered. Results showed significant differences in specific growth rate (SGR), percentage weight gain (WG), feed conversion ratio (FCR), and condition factor (cf) of experiment group 1 and group 3. Survival rates of the experiment groups 2and 3 were significantly different from those of the experiment control group and 1. twenty first feeding day of the study showed ration oral size to body length was evaluated by (0 /1 ± 0/01) mm. This study demonstrated that Brachionus calyciflorus is a suitable live food for larval feeding and can be cultured, enriched and used along with other freshwater rotifers.
