Abstract

The intensive aquaculture industry faces two main problems, first, the decrease in the water quality caused by high concentrations of metabolites, and second, the use of low natural food in aquaculture activities with high water exchange intensity. For this reason, efforts are needed to develop biofloc to maximize the contribution of natural food which can increase aquaculture production. The present study aimed to analyze the effect of commercial probiotics on the differences in the phytoplankton diversity associated with biofloc. The fish were divided into three treatment groups. Treatment A involved biofloc formation without using probiotics, treatment B contained biofloc formation using commercial probiotics (Bacillus spp., lactic acid, Lactobacillus spp., Saccharomyces spp. 50/50 feed), and treatment C entailed biofloc formation using commercial probiotics (containing a native microbial consortium, 50/50 feed). The treatment groups were repeated six times so that there were 18 experimental units. The research was conducted from March to April 2015. The results indicated that the administration of probiotics with different types led to insignificant differences among the treatment groups. The highest diversity index value occurred in treatment C on day 34 of the experiment that was equal to 0.49. On the other hand, the highest value of the dominance index (C = 0.99) occurred in treatments A and B on day 21. It can be concluded that the addition of probiotics with different biofloc could result in insignificant phytoplankton diversity. Furthermore, the Nitrogen/Phosphorus (N/P) ratio as a limiting factor for phytoplankton growth indicated different results in each treatment.