Application of Preserved Phytoplankton (Chaetoceros sp.) and Rotifer (Brachionus rotundiformis) in Concentrate Form for Larviculture of Whiteleg Shrimp (Litopenaeus vannamei) and Blue Swimming Crab (Portunus pelagicus)

Abstract

The objectives of this study were to investigate the preservation of diatom microalgae (Chaetoceros sp.) for whiteleg shrimp (Litopenaeus vannamei) larviculture and of marine rotifer (Brachionus rotundiformis) for blue swimming crab (Portunus pelagicus) larviculture. Both feed stored in concentrate form and by biomass-freezing at -20 ºC with 2% trehalose as cryoprotectant agents (w/w) at 2-4 weeks (T1), 6-8 weeks (T2) and 10-12 weeks (T3) were compared to the traditional method using alive Chaetoceros and alive rotifer (control) to nurse L. vannamei larvae from zoea 1 to post larva stages and P. pelagicus larvae from zoea 1 to magalopa stages, respectively. The results showed that survival rate of shrimp larvae fed with control feed (53.3±11.5%) was significantly higher than those of T1 (0%), T2 (0%) and T3 (0%) (p<0.05) and found that concentrated Chaetoceros affects water quality and quantity of Vibrio bacteria during shrimp larviculture. Additionally, survival rate of blue swimming crab larvae fed with traditional method, T1, T2 and T3 were 26.6±5.7%, 30.0±10.0%, 26.6±11.5% and 23.3±5.7%, respectively. This indicated non-significant (p>0.05) difference. The average of water quality and quantity of Vibrio bacteria in each treatment were not significantly different (p>0.05). This study revealed that there is high possibility to use 2-8 weeks stored rotifer for P. pelagicus larviculture while 2-12 weeks stored Chaetoceros is not possible to use for L. vannamei larviculture.