Enhancing Growth and Immune Responses in Giant Freshwater Prawn (Macrobrachium rosenbergii) via Oral Administration of Mouri (Foeniculum vulgare) Extracts against Vibrio parahaemolyticus

The present study evaluated the dietary impact of ethanolic extract of Foeniculum vulgare (FV) on the growth performance and immunological resilience of Giant River Prawn (Macrobrachium rosenbergii). Prior to selecting FV as a dietary supplement, a comprehensive screening of 24 spices with 4 solvents was conducted, with FV demonstrating the highest antimicrobial efficacy against Vibrio parahaemolyticus and minimal cytotoxicity on Artemia, highlighting its excellent bioactivity and potential for therapeutic applications. After that, juvenile prawns (initial weight 2.1 ± 0.25 g) were randomly distributed across nine fiberglass tanks, corresponding to two dietary treatments, with each tank housing 15 prawns. The control group (C) received a basal diet with no supplementation, while two experimental groups were fed diets enriched with 2.5 g/kg (0.25 %) (FV1) and 5.00 g/kg (0.5 %) (FV2) (with 3 replications) of F. vulgare ethanolic extract. Prawns were fed at 5% of their body weight daily for four weeks. After the experimental period, growth performance metrics including Final Weight (FW), Average Weight Gain (AWG), Specific Growth Rate (SGR), and Feed Conversion Ratio (FCR)—were assessed, along with immunological parameters such as Total Hemocyte Count (THC), Differential Hemocyte Count (DHC), Hemolymph Clotting Time (HCT), Superoxide Anion Production, Respiratory Burst activity (RBs) and Pro-phenoloxidase activity (proPO). The FV1 group (2.5 g/kg diet) demonstrated significantly higher growth performance, feed efficiency and enhanced immunological responses of prawn compared to control and FV2 groups. These findings indicate that dietary inclusion of F. vulgare extract at 2.5 g/kg optimizes growth performance, feed utilization, and antioxidant activity in M.
rosenbergii. This work underscores the potential of spice-based additives in sustainable aquaculture practices, offering a natural alternative to enhance productivity and health in aquatic species.

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