Prevention of Vibriosis using whole cell microalgae on tiger shrimp hatcheries

In this study, a trial was conducted to use whole cell microalgae Porphyridium sp and Porphyridium aerugineum as an alternative material for preventing Vibriosis. This study used three treatments with three replications each. Treatment A was Control without microalgae administration, Treatment B was given Porphyridium aerugineum and treatment C was given Porphyridium sp. The microalgae were given in Zoea1, Mysis1, PL 2, PL 6, and PL 10 phases with the density of microalgae at the time of stocking was 105 - 106 cells/mL. Larval rearing was carried out for 19 days until Post Larva 12. The parameters observed were the density of microalgae in the rearing container and the density of Vibrio bacteria. Sampling for microalgae density observations was carried out every day from the zoea phase 2 to PL 10. Sampling of bacterial density was carried out at every phase change along with observing water quality parameters. At the end of the fry rearing period (PL 12), a challenge test was performed using V. parahaemolyticus bacteria with a density of 107 CFU/mL. Shrimp survival during the challenge test was observed every day until the fifth day. In addition, the density of Vibrio bacteria was also observed. The results showed that the administration of P. aerugineum could suppress the population of Vibrio bacteria and the ratio of Vibrio bacteria to common bacteria was better than the control. On the other hand, the highest survival rate for shrimp was treated with Porphyridium sp. After the challenge test, the best survival results were also obtained in the treatment with Porphyridium sp.