The study evaluated the effects of dietary doses of Lactobacillus plantarum VSG3 on the growth performance,
immunity, and disease resistance of Labeo rohita juveniles against Aeromonas hydrophila infection.
Fish (mean body weight 60 g) were fed with diet containing 0 (control), 106, 108, 1010 cfu g1
L. plantarum VSG3 for 60 days. Various growth and immune parameters were examined at 30 and 60
days of post-feeding. Fish were challenged with A. hydrophila 60 days post-feeding and mortalities were
recorded over 10 days post-infection. Results showed that administration of VSG3 for 60 days had
significant effects (P < 0.05) on the specific growth rate (SGR) and feed utilization efficiency of L. rohita.
Dietary administration of L. plantarum VSG3 significantly increased the serum lysozyme and alternative
complement pathway (ACP) activities, phagocytosis and respiratory burst activity in L. rohita throughout
the experimental period. The highest superoxide dismutase (SOD) activity (P < 0.05) was observed in the
fish group fed diet containing VSG3 at 108 cfu g1. The serum IgM levels were significantly higher in the
experimental groups compared to the control group after 30 days of feeding; but, the result was opposite
after 60 days of feeding. Further, fish fed the diet containing 108 cfu g1 L. plantarum VSG3 had significantly
higher (P < 0.05) post-challenge survival rate (77.7%). These results collectively suggest that
dietary supplementation of L. plantarum VSG3 at 108 cfu g1 to L. rohita is optimal for enhancing the
growth, immunity, and disease resistance against A. hydrophila infection.