Valorization of Invasive Aquatic Weed (Eichhornia crassipes) Into a Sustainable Carbon Source in GIFT-Based Biofloc...

Biofloc technology (BFT) has emerged as a sustainable aquaculture strategy, enabling high productivity with minimal water and land use. While diverse carbon sources are employed in BFT systems, identifying cost-effective and locally available alternatives can enhance profitability and adoption among farmers. This study evaluated the efficiency of five carbon sources, rice water (T1), jaggery (T2), sugar (T3), Eichhornia crassipes (T4), and a mixture of E. crassipes and jaggery (T5), compared to a control (CN) group without biofloc. Genetically improved farmed tilapia (GIFT) tilapia fry (10 fish per tank) were cultured for 60 days in triplicate tanks under controlled indoor conditions. After 15 days, all BFT treatments showed significantly higher weight gain than the CN (p  < 0.05). Although T2 achieved the highest weight gain overall, the differences from T4 and T5 were not significant by Days 45 and 60 (p  > 0.05). No significant differences were observed among BFT treatments in specific growth rate (SGR), daily weight gain, feed conversion ratio (FCR), or survival rate. Water quality parameters remained within optimal ranges, although total alkalinity declined across treatments from Day 15 onwards. Significant variation (p  < 0.05) was found in ammonia, nitrite, and nitrate concentrations among treatments throughout the trial. Floc volume (FV) increased steadily, peaking at Day 60 in the order T2 > T3 > T4 > T5 > T1. Floc porosity in T1 declined from 99.8% to 97.73%. Total solids were highest in T4 and T5. Bacterial counts were significantly greater in all BFT treatments compared to the CN (p  < 0.05). The results demonstrate that E. crassipes, alone or combined with jaggery, is an effective carbon source in BFT systems, supporting robust growth, microbial activity, and water quality. This approach offers an eco-friendly, low-cost strategy for improving the sustainability and economic viability of tilapia aquaculture.