Stimulation of immunity in Indian major carp Catla catla with herbal feed ingredients Vasudeva Rao Y., Rina Chakrabarti* Department of Zoology, University of Delhi, Delhi 110 007, India Received 16 March 2004; accepted 5 August 2004 Available online 3 November 2004 Abstract Catla catla, catla (150 G 20 g) were fed a diet containing seed of Achyranthes aspera (0.5%) and control diet without A. aspera for four weeks prior to and after ip injection with chicken erythrocytes. Fish were sampled for four consecutive weeks after immunization. Hemagglutination antibody titers were significantly higher in the test group of fishes compared with the control group. Serum globulin levels were significantly (P t-test ! 0.05) higher in the test group than control group on days 14 and 21. Anti-trypsin activity due to total serum protease inhibitors and a1-antiprotease was also significantly (P t-test ! 0.05) higher in the test group of fishes than the control. RNA/DNA ratio of spleen and kidney was also significantly (P t-test ! 0.05) higher in test group than the control group. All these results confirm that A. aspera enhances the immunity of catla. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Catla (Catla catla); Achyranthes aspera; Immunostimulation; Antigen-specific antibody response; Anti-proteases 1. Introduction Immunostimulants increase resistance to infectious diseases by enhancing both specific and non-specific defense mechanisms. Enhanced non-specific immunity against various bacterial fish pathogens (Aeromonas hydrophila, Vibrio anguillarum, Vibrio salmonicida, Yersinia ruckeri) with glucans derived from Schizophyllum commune and Saccharomyces cerevisiae has been reported [1,2]. Oral administration of peptidoglycan increased resistance to V. anguillarum in rainbow trout Oncorhyncus mykiss [3] and oral treatment with glucans increased resistance to V. anguillarum and V. salmonicida in Atlantic salmon Salmo salar [4]. Injection of chitin increased the resistance in brook trout [5] and in rainbow trout [6] and injection * Corresponding author. Tel.: C91 11 27666496. E-mail address: rina@ndf.vsnl.net.in (R. Chakrabarti). 1050-4648/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.fsi.2004.08.005 Fish & Shellfish Immunology 18 (2005) 327e334 www.elsevier.com/locate/fsi