Ajwain (Trachyspermum ammi) seed extract: A natural strategy to improve growth, immunity and disease resistance in Macrobrachium rosenbergii against Vibrio parahaemolyticus infections.

This study evaluated the effects of dietary supplementation with Trachyspermum ammi (ajwain) seed extract on growth performance, immune response, physiological status, and disease resistance in the giant freshwater prawn (Macrobrachium rosenbergii) against Vibrio parahaemolyticus. Juvenile prawns (2.1 ± 0.25 g) were fed diets supplemented with three levels of T. ammi extract (0%, 0.025%, and 0.05%) for 8 weeks, followed by a bacterial challenge with V. parahaemolyticus (106 CFU/mL) and a 14-day observation period. Prawns receiving ajwain-supplemented diets showed improved growth performance, including higher final weight, weight gain, and specific growth rate, together with improved feed utilization efficiency. Immune-related parameters, including total hemocyte count, hemolymph clotting time, prophenoloxidase activity, respiratory burst activity, superoxide anion production, and superoxide dismutase activity, were significantly enhanced compared to the control group, although responses varied among parameters and sampling periods. Dietary inclusion of T. ammi extract modified whole body composition with increased protein content in both supplemented groups compared with the control, while the lower dose showed the highest protein deposition. The higher dose resulted in greater lipid and ash accumulation, suggesting dose-dependent differences in nutrient allocation. Digestive enzyme activities (protease and amylase) were also significantly stimulated. Following the V. parahaemolyticus challenge, extract-treated groups showed improved survival, with the higher inclusion levels demonstrating the greatest resistance to infection. These findings indicate that T. ammi seed extract has potential as an effective natural feed additive to enhance growth, immunity, and disease resistance in M. rosenbergii; however, further molecular investigations are required to clarify the underlying mechanisms.