author(s)
Md. Hasan-Uj-Jaman, Md. Mer Mosharraf Hossain, Jannatul Ferdaus, Hafeza Sultana Rosny, Md. Tareq Ahmed, Sayadatunnasa Jenny

abstract
Indian major carp, rohu, (Labeo rohita) (30±6g), were fed with two types of diets; an experimental diet, containing root extract (0.5%) of Achyranthes aspera as an ingredient and control diet without the root extract. Experimental rohu were injected intraperitoneally with Pseudomonas fluorescens (3.2×10^-6 CFU ml^-1) and bloods were sampled 14 and 28 days post immunization. Though hemagglutination antibody (HA) titers were always higher in the test group than the control group, antigen-specific antibody and total serum globulin levels peaked on day 14 after immunization and steadily reduced towards day 28. Beside this, the results showed that dietary supplementation of A. aspera in test group showed significantly increased serum antibody titer (3280) and growth factors (41.1%) of L. rohita (P<0.05) compared with the control group throughout the experimental period. The RNA/DNA ratio was significantly (P<0.05) higher in test group of fish than the control group on days 7 and 14. These results showed the immunostimulatory activity of the prepared diet containing root extract of A. aspera.