ETHANOL AND METHANOL EXTRACTS OF Withania somnifera ROOT ENHANCES INNATE IMMUNITY AND PROMOTES GROWTH IN NILE TILAPIA Oreochromis niloticus

Efficacy of ethanol and methanol extracts of medicinal herb Withania somnifera roots were evaluated in tilapia, Oreochromis niloticus on immunostimulation and growth. Withania roots were extracted with water, ethanol, methanol, methylene chloride, hexane, successive methanol. Phenol, flavonoid content and antiradical activity of all the extracts were measured. Ethanol extract showed the highest phenol, flavonoid content and antiradical activity followed by methanol extract. Subsequently, Nile tilapia (mean weight 25.00±0.40 g) were fed diets containing different concentrations (0.0, 0.3, 0.5 and 0.7 g kg-1 feed) of ethanol and methanol extracts of W. somnifera roots for 30 days (n = 126, 3 replicates). Fish fed plant extract fortified diets showed significantly better (P<0.05) immunological, haematological, biochemical and growth parameters compared to fish fed control diet. Fish fed diet containing ethanol extract at the concentration of 0.7 g kg-1 feed showed the highest immunological (phagocytotic activity, respiratory burst activity, serum lysozyme, total protein, total immunoglobulin), haematological (total red blood cells, haemoglobin, hematocrit, total white blood cells, lymphocyte), biochemical (reduced glutathione, glutathione reductase activity) and growth (final weight, weight gain, daily weight gain, specific growth rate) parameters. The plant extract might act as potent free radical scavenger in fish tissues, and have tissue protecting ability, thus increasing fish health.