Influence of immobilized microalgaes on the quantity of bacteria of shrimp

With the immobilization for alginate beads , Oocystis borgei snaow and Nannocgloris oculata were introduced into the cultural environment of shrimp, Litopenaeus vannamei. Numberical dynamics of heterotrophic bacteria and Vibrio in the water, muscle and hepatopancreaty of shrimp were inspected by direct counting. The results show that these two microalage alginate beads can inhibit growth of heterotrophic bacteria and Vibrio. At last, compared to constrol group, the number of Vibrio in water of tested group1, 2, 3 declined 95%, 95%, 81.7% when the number of hepatopancreas declined 72.3%, 77.1%, 95.6%, respectively. Meanwhile, concentration of NH3-N and NO2-N of control group were 60.8%, 81.4%, 7.1% higher than tested group1, 2 and 3 respectively. Furthermore, the number of microalage beads can be adjusted to keep balance of the water system. Using microalage alginate beads ecology is an important measure to inhibit growth of heterotrophic bacteria and Vibrio and to adjust water quality for preventing the shrimp disease.