Protective Role of Morus alba Extract Against Vibrio cholerae: Impacts on Growth, Biochemical and Enzymatic Responses, Haematoimmunology, and Tissue Histopathology in Dormitator latifrons

The use of phytobiotics in aquafeeds is a promising strategy to enhance performance and resilience to disease. This study evaluated the protective role of <i>Morus alba</i> (MA) extract against <i>Vibrio cholerae</i>, integrating in vivo responses in <i>Dormitator latifrons</i> (growth, biochemical and enzymatic responses, haemato-immunology and tissue histopathology) with in vitro assessment of <i>V. cholerae</i> growth, virulence-associated gene expression and cellular morphology. <i>D. latifrons</i> juveniles were fed five diets (0, 5, 10, 15 and 20 g/kg feed; three tanks per treatment, 15 fish per tank) for eight weeks, followed by a 7-day challenge with <i>V. cholerae</i>. MA increased growth and feed utilisation (<i>p</i> < 0.05); the 20 g/kg group reached 27.57 g final weight with a feed conversion ratio of 1.24, and whole-body protein and lipid contents rose at higher doses. MA modulated plasma biochemistry and key digestive (amylase, lipase), metabolic (ALT, AST) and antioxidant (SOD, CAT, GPx) enzymes, and improved haematological profiles. Histology of the intestine, liver and spleen showed preserved architecture and reinforced mucosal features in supplemented fish, particularly at 15-20 g/kg. Post-challenge, supplemented groups exhibited higher survival/relative protection than controls, alongside lower transaminases and stronger antioxidant responses. In vitro, MA extract inhibited <i>V. cholerae</i> growth, attenuated virulence-associated gene (<i>toxR, ompU</i>) expression and induced marked morphological damage in planktonic cells. Multivariate analyses (Z-score heatmaps and PCA) linked immune-enzymatic improvements with growth and protection. Overall, 15-20 g/kg MA optimised immunophysiological status and disease resistance, supporting MA as a functional feed additive for sustainable aquaculture of <i>D. latifrons</i>.