Effects of Bioflocs Enriched With Chlorella sorokiniana and Scenedesmus sp. on the Performance of Nile Tilapia ( Oreochromis niloticus ) in a Biofloc Technology System

Aquaculture faces significant challenges, including water pollution and low productivity in traditional systems. Biofloc technology (BFT) offers a sustainable alternative by recycling nutrients and improving water quality. The present study assessed the efficacy of bioflocs enriched with the freshwater microalgae such as Chlorella sorokiniana and Scenedesmus sp. in Nile tilapia ( Oreochromis niloticus ) culture. Four treatments were tested; the biofloc systems were inoculated with i) control group without microalgae inoculation, ii) C. sorokiniana in an initial density of 1 × 10 6 cells/mL, iii) Scenedesmus sp. (1 × 10 6 cells/mL), and iv) mixed culture (1 × 10 6 cells/mL for each species). Growth performance, proximal composition of bioflocs, hematological parameters, and water quality were analyzed. Results demonstrated that treatment with C. sorokiniana achieved the highest biomass (6.9 × 10 6 cells/mL) compared to the treatment with Scenedesmus sp., (2.8 × 10 6 cells/mL) as well as better nutritional composition in C. sorokiniana treatment. Tilapia reared in the C. sorokiniana biofloc system showed significantly higher final body weight (63.51 g), weight gain (WG; 55.77 g), specific growth rate (SGR; 3.01% day −1 ), and improved feed utilization ( p < 0.05) compared to the control and other treatments. This treatment also optimized water quality, reducing nitrite levels to 2.68 mg/L, compared to 4.27 mg/L in the control group. Hematological parameters did not differ significantly among treatments, indicating no adverse physiological effects. The mixed algae biofloc treatment yielded no synergistic benefits, likely due to interspecies competition. Overall, the incorporation of C. sorokiniana ‐enriched bioflocs significantly enhances tilapia performance and water quality, demonstrating their potential for sustainable aquaculture.