Effect of synbiotics on the survival and immune response of whiteleg shrimp, <i>Litopenaeus vannamei</i> under acute salinity and ammonia stress

The present study aims to evaluate the effects of noni leaf extract, Lactobacillus plantarum CMT1, and their combination (synbiotic) on the immune response of whiteleg shrimp under environmental stress conditions. Juvenile shrimp were fed four different experimental diets for 60 days: (1) a control diet, (2) a prebiotic diet supplemented with 1% noni leaf extract, (3) a probiotic diet containing 10⁸ CFU/kg of L. plantarum CMT1, and (4) a synbiotic diet supplemented with both 1% noni leaf extract and 10⁸ CFU/kg of L. plantarum CMT1. After 60 days of culture, shrimp in all treatments were exposed to salinity or ammonia stress for a period of 48 h. The results showed that administering synbiotic treatments for 60 days resulted in higher immune parameters, including total hemocyte count, phenoloxidase activity, and hemocyanin concentration, compared to the control, both before and after exposure to salinity or ammonia stress. After 48 hours of ammonia exposure, synbiotic treatments showed higher survival rate compared to the control treatment. However, no shrimp mortality was observed in any treatment following salinity stress conditions. In summary, the combination of noni leaf extract and Lactobacillus plantarum CMT1 could serve as a promising strategy to enhance the immune response of shrimp under acute stressful conditions associated with climate change.