Effect of water hyacinth leaf supplementation in the performance of caged common carp (cyprinus carpio) were evaluated. The different levels of water hyacinth leaf meal supplementation in the different experimental diets were 0%, 10%, 15% and 20% (with crude protein content of 30%). The performance were evaluated using 12 cages (1 m3) at Institute of Agriculture and Animal Science, Paklihawa campus, Bhairahawa for 90 days (26th August of 2023 to 19th November of 2023). Common carp fries were randomly distributed into cages at 10 fry/ cage. The experiment were conducted in Completely Randomized Design (CRD) with four treatments replicated thrice. The treatments were: T1: Control (Basal diet), T2: 10% replacement of Soybean Meal (SBM) with Water Hyacinth Leaf Meal (WHLM) in Basal diet, T3: 15 % replacement of SBM with WHLM in Basal diet, T4: 20 % replacement of SBM with WHLM in Basal diet. The pelleted feed containing 35% CP were maintained at the rate of 5% of body weight in initial month followed by 3% in the following months. Fish were fed once daily at morning between 8:00-9:00 a.m. Mean weight of fry during stocking period were 46.5±7.16g, 45.4±6.54 g, 45.3±4.46 g, 41.6±1.73g in treatments T1, T2, T3 and T4 respectively. Final mean weight of fish was highest in T3 (159.3±6.23g) at the 90 days after stocking which were significantly higher than T1 (123.6±8.12g), T2 (131.6±7.21g), T4 (108.4±1.74g) at (p<0.05). Similarly, the Specific Growth rate (SGR) value was highest (1.4±0.06g) in T3 while T4 (1.0±0.04g) was found to be the lowest. The survivability was recorded in a range of (76.6-90). Highest Benefit Cost ratio (BCR) was recorded in T3 (1.27±0.01) which were significantly different with T1(0.94±0.02), T2(1.04±0.02) and T4(0.97±0.008) (p<0.05). The gross return was found highest in T3 (58.95±2.30) and lowest T4(40.12±0.64) (p<0.05) while the net return was also highest in T3 (12.69±1.65) and lowest in T1 (2.43±1.34) (p< 0.05). So, we can suggest T3 (Replacement of 15% water hyacinth powder) as partial alternative of soya bean meal powder in fish feed.
Pandit et al. (Wed,) studied this question.