Nymphoides peltata as a potential protein source to replace fish meal in the diet of Common Carp, Cyprinus carpio var. communis

The present study assessed the proximate composition of three aquatic weeds—Nymphoides peltata, Ceratophyllum demersum, and Potamogeton nodosus—to explore their potential as alternative feed ingredients for aquaculture. Among the species analyzed, Nymphoides peltata exhibited the highest crude protein (25%), dry matter (93.60%), and crude fat (5.64%) contents. Based on these results, N. peltata was selected for dietary inclusion in the feed of Common carp (Cyprinus carpio). Four isonitrogenous (35% CP) and isocaloric (3500 kcal/kg) diets were formulated with N. peltata incorporated at 0% (control), 15% (T1), 30% (T2), and 45% (T3). Juvenile carp (average weight 8.95±1.1 g) were fed the experimental diets at 5% of their body weight daily for eight weeks. Growth performance and feed utilization metrics indicated that fish fed the 45% inclusion diet (T3) had significantly higher (P < 0.05) weight gain (17.09±0.55 g) and specific growth rate (1.106 ± 0.01) compared to the control. Feed conversion ratio (2.81±0.19) was lowest, and protein efficiency ratio (1.78±0.07) highest in T3. Mortality was lowest in the control and T3 groups. The findings demonstrate that Nymphoides peltata can be effectively used as a partial fishmeal replacer, enhancing growth and feed efficiency in C. carpio without adverse effects on survival. This highlights its potential as a sustainable and cost-effective ingredient for aqua feeds.