Effects of the biofloc technology and decreased feeding rates on growth, water quality, and microbial dynamics in Litopenaeus vannamei culture

The Pacific white shrimp (Litopenaeus vannamei) dominates global aquaculture, but intensive systems face challenges from high feed costs and deteriorating water quality. Biofloc technology offers a sustainable solution by enhancing nutrient recycling and water quality. However, the effects of reduced feeding rate (FR) in biofloc systems remain underexplored. This study evaluated the impact of reduced feeding rates on shrimp performance, water quality, and microbial communities in a 30-day trial with four treatments: Control (non-biofloc, established FR), Bio (biofloc, established FR), Bio-25% (biofloc, 25% FR reduction), and Bio-50% (biofloc, 50% FR reduction), each in triplicate using shrimp (2.94 ± 0.16 g; 40 shrimp per 96 L tank). Biofloc was developed by maintaining a 10:1 C/N ratio using molasses and weekly probiotics addition (5 g/m³). Results showed that Bio-25% achieved the highest final weight (8.11 g), daily growth rate (0.191 g/day), and a more favorable feed conversion ratio (0.94) without reducing survival. Water quality parameters remained within acceptable limits, and biofloc treatments showed higher floc volume. Microbial analysis revealed lower Vibrio counts and higher Bacillus spp. in Bio-25%. Collectively, in biofloc systems, a 25% feed restriction maximizes microbial stability, water quality, and shrimp performance, offering a cost-effective strategy for sustainable aquaculture.