Evaluation of water quality and physiological responses of Pacific whiteleg shrimp (Litopenaeus vannamei) in culture water with different abundances of Oscillatoria sp. under laboratory condition
摘要
Rising global demand for Litopenaeus vannamei has led to increased production in Indonesia. However, fluctuations in water quality create favorable conditions for cyanobacteria, especially Oscillatoria spp. which often dominate phytoplankton communities in areas such as Java. Data from shrimp ponds in Indramayu and Serang confirm this dominance. The prevalence of cyanobacteria was positively correlated with disease outbreaks in shrimp ponds. This study comprises two main phases: the isolation and cultivation of Oscillatoria sp., followed by the rearing of L. vannamei in an environment enriched with Oscillatoria sp. at abundance of 104 (P4), 105 (P5), and 106 (P6) ind mL−1 for 14 days. The results showed a decrease in water quality, particularly in chemical and bilogical parameters. The lowest pH values were 6.23 and 6.12 in P6 at the morning and evening sampling times, respectively. The decrease in alkalinity occurred along with the increasing abundance of Oscillatoria added to the maintenance media (the lowest value was 53 mg L−1 in P6) while the abundance of Vibrio sp. colonies was highest in P6 at 325,333 CFU mL−1. The presence of Oscillatoria negatively affects L. vannamei production, leading to lower final weight, slower growth, and higher feed conversion ratio. Based on these findings, effective water quality management is crucial, and water exchange should be implemented before Oscillatoria abundance reaches 105 cells mL−1.