Growth performance and immunomodulatory effect of Terminalia catappa L. diet on Litopenaeus vannamei against Vibrio parahaemolyticus challenge.

Shrimp is a popular commodity due to its fast growth and high economic value. However, stress-related disease outbreaks caused by intensifying agricultural practices and environmental factors have led to significant financial losses globally. Using chemical compounds to combat infectious pathogens has also led to antibiotic resistance and accumulation of residues in tissues and the environment, posing consumer risks. This study investigated the potential benefits of Terminalia catappa leaves (TCL) as a natural plant product-based dietary supplement for Litopenaeus vannamei postlarvae against Vibrio parahaemolyticus infection. Experimental diets with TCL extract were prepared and the feeding trial was carried out for 28 days with L. vannamei postlarvae (PL10). The growth parameters and digestive enzymes were measured. Vibrio challenge test was conducted for 48 h. Oxidative stress, immunomodulation and histopathology of hepatopancreases were analysed after vibrio challenge in PL given with/without TCL diet. The study revealed that TCL diet has an increased body weight and survival rate of the shrimp than basal diet via increasing digestive enzyme activity. TCL diet also increases the survival of shrimp against the vibrio challenge. It increases antioxidant enzymes and eliminates oxidative stress. TCL acts as an immunostimulant by increasing prophenoloxidase, crustin, lysozyme and penaeid 3a genes. Moreover, the cellular damage caused by oxidative stress to hepatopancreases of the shrimp was reduced. The findings in this study suggest that the TCL diet has a dual property of growth promoter and immunostimulant and can be a sustainable and cost-effective alternative to traditional aquaculture practices. [ABSTRACT FROM AUTHOR]