Synergistic effects of Neem and Moringa on fish (Labeo rohita) health: a challenge study with Saprolegnia parasitica

Aim: To investigate the synergistic effects of Neem (Azadirachta indica) and Moringa (Moringa oleifera) leaves supplementation on the growth, health, immune response, and resistance to Saprolegnia parasitica infection in Labeo rohita under the agro-climatic conditions of Meghalaya, India. Methodology: Four experimental diets (isonitrogenous and isocaloric) were tested over a 8-week feeding trial: Control (C), Neem-supplemented (N), Moringa-supplemented (M), and Neem+Moringa-supplemented (NM). Growth performance, feed utilization, hematological parameters and immune indices were measured. Fish were then challenged with S. parasitica (1×105 spores m l-1) and monitored for 14 days. Results: The NM group exhibited significantly improved growth performance, feed conversion ratio, hematological parameters, and immune indices compared to other groups. Following the challenge, the NM group showed the highest survival rate (86.7%) and lowest infection severity. Interpretation: Combined supplementation of Neem and Moringa in L. rohita diets can enhance growth, immunity and disease resistance, offering a promising strategy for sustainable aquaculture in Meghalaya and potentially other regions with similar agro-climatic conditions. Key words: Immunostimulation, Labeo rohita, Moringa oleifera, Neem, Saprolegnia parasitica, Synergistic effects