Utilising water hyacinth (Eichhornia crassipes) in Nile tilapia (Oreochromis niloticus) diets: Effects on growth, digestibility, and optimal inclusion rate

This study investigates the potential of water hyacinth (Eichhornia crassipes) leaves as a protein-rich dietary alternative for Oreochromis niloticus (Nile tilapia). Water hyacinth is an invasive aquatic plant with promising nutritional properties, including moderate protein content and low levels of antinutritional factors. The digestibility of WH leaves was assessed, and their optimal incorporation level in fish feed was evaluated. Apparent digestibility coefficients (ADCs) for WH leaf were 77.49% (dry matter), 69.58% (crude protein), and 59.14% (energy). Six experimental diets containing 0–12% WH leaf were formulated and fed to O. niloticus fingerlings over 45 days. Growth performance, feed utilisation, and carcass composition were analysed. Results showed that inclusion levels up to 6% did not significantly affect growth, feed conversion ratio, or protein efficiency; however, inclusion levels above 6% led to reduced zootechnical performance and a lower nutritional quality of fish flesh. Survival rates remained unaffected across all treatments. The study concludes that WH leaves can be safely included in tilapia diets at a maximum of 6% without adverse effects on growth, feed efficiency, or flesh quality, offering a sustainable feed alternative in aquaculture.