Evaluation of Eichhornia-based Fermented Silage as a Partial Protein Substitute for Groundnut Oil Cake in Growth and Water Quality of Rohu (Labeo rohita)

Abstract

This study evaluated the potential of Eichhornia-based fermented silage (EFS) as an alternative protein source to groundnut oil cake (GNOC) in the diet of rohu (Labeo rohita), focusing on growth performance, feed utilization, economics, water quality, and genotoxic safety. A completely randomized design with five dietary treatments, each with three replications. The experiment was conducted under controlled laboratory conditions for 60 days. Five isonitrogenous (25% crude protein) and isolipidic (8% lipid) diets were formulated by replacing GNOC with EFS at 0% (C), 25% (T1), 50% (T2), 75% (T3), and 100% (T4). Rohu fingerlings (0.79 ± 0.04 g) were stocked at 1 g/L and fed at 10% body weight for the first 30 days and 8% thereafter. Growth performance, feed utilization indices, somatic indices, water quality, economic parameters, and genotoxicity (as assessed by the comet assay) were evaluated. EFS showed higher crude protein content than raw Eichhornia. Growth parameters (BWG, SGR, FCE, PER, and LER) declined with increasing EFS inclusion, while FCR increased. T1 showed no significant difference (p > 0.05) compared to the control. HSI and ISI were non-significant across treatments, except T1, which exhibited a lower HSI. Feed cost per kilogram and economic conversion ratio decreased with higher EFS inclusion. No DNA damage was observed in any treatment group. EFS can replace GNOC up to 25% in rohu diets without adverse effects on growth or health, offering a safe and economically feasible alternative protein source.