The present study evaluated the efficacy of dietary doses of Withania somnifera (
Ashwagandha) root
powder on immunological parameters and
disease resistance against the bacterial pathogen Aeromonas hydrophila
infections in Indian major carp, Labeo rohita fingerlings. Fishes were fed with dry diet containing 0 gkg(-1) (control), 1 gkg(-1) (T(1)), 2 gkg(-1) (T(2)) and 3 gkg(-1) (T(3)) W. somnifera root
powder for 42 days. Immunological (NBT level, Phagocytic activity, total
immunoglobulin and
lysozyme activity) parameters of fishes were examined at 0 days, 14 days, 28 days and 42 days of feeding. Fishes were challenged with A. hydrophila 42 days post feeding and mortalities (%) were recorded over 14 days post-
infection. The results demonstrate that fishes fed with W. somnifera root showed enhanced NBT level, Phagocytic activity, total
Immunoglobulin level and
lysozyme activity (p<0.05) compared with the control group. The survivability was higher in experimental diets than the control group. Dietary W. somnifera at the level of 2 gkg(-1) showed significantly (P<0.05) higher protection (RPS 42.85+/-0.65%) against A. hydrophila
infection than control. The results suggest that the W. somnifera root
powder have a stimulatory effect on immunological parameters and increases
disease resistance in L. rohita fingerlings against A. hydrophila
infection.