~ 1674 ~ Journal of Entomology and Zoology Studies 2020; 8(5): 1674-1680 E-ISSN: 2320-7078 P-ISSN: 2349-6800 www.entomoljournal.com JEZS 2020; 8(5): 1674-1680 © 2020 JEZS Received: 20-07-2020 Accepted: 25-08-2020 Avijit Biswas Assistant Professor, School of Fisheries, Centurion University of Technology and Management, Odisha, India Dr. Gadadhar Dash Professor, Department of Aquatic Animal Health, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, Chakgaria, Panchasayar, Kolkata, West Bengal, India Prasenjit Mali Assistant Professor, Department of Aquatic Animal Health, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, Chakgaria, Panchasayar, Kolkata, West Bengal, India Dr. Siddhartha Narayan Joardar Professor, Department of Veterinary Microbiology, Faculty of Veterinary and Animal Sciences West Bengal University of Animal and Fishery Sciences, Kshudiram Bose Sarani, Belgachia, Kolkata, West Bengal, India Dr. T Jawahar Abraham Professor, Department of Aquatic Animal Health, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, Chakgaria, Panchasayar, Kolkata, West Bengal, India Sutanu Karmakar Assistant Professor, Department of Aquatic Environment Management, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, Chakgaria, Panchasayar, Kolkata, West Bengal, India Debapriyo Mukherjee Senior Research Fellow, National Surveillance Programme for Aquatic Animal Diseases, Department of Aquatic Animal Health, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, Chakgaria, Panchasayar, Kolkata, West Bengal, India Dr. Koel Bhattacharya Sanyal Senior Research Fellow, National Surveillance Programme for Aquatic Animal Diseases, Department of Aquatic Animal Health, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, Kolkata, West Bengal, India Corresponding Author: Prasenjit Mali Assistant Professor, Department of Aquatic Animal Health, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, Chakgaria, Panchasayar, Kolkata, West Bengal, India Vaccine potentiality of different antigenic preparations of Aeromonas hydrophila in Rohu, Labeo rohita Ham Avijit Biswas, Dr. Gadadhar Dash, Prasenjit Mali, Dr. Siddhartha Narayan Joardar, Dr. T Jawahar Abraham, Sutanu Karmakar, Debapriyo Mukherjee and Dr. Koel Bhattacharya Sanyal DOI: https://doi.org/10.22271/j.ento.2020.v8.i5w.7738 Abstract To develop vaccine for rohu (Labeo rohita), efficacy of three antigenic preparations from Aeromonas hydrophila were evaluated. Thirty six tanks with ten rohu were divided in quadruplicates (R1 to R4) with nine tanks (G1 to G9). Rohu of G1 to G6 tanks were given intraperitoneal vaccine with outer membrane protein, somatic protein and formalin-inactivated whole cell itself and along with Incomplete Freund’s Adjuvant @ 200 μg/fish, G7 and G8 tanks were injected with Incomplete Freund’s Adjuvant (100 µl/fish) and normal saline (100 μl/fish) respectively and G9 tanks were kept as control. After 28 d, rohu of R3 and R4 were subjected to intramuscular A. hydrophila challenge (LD50) @ 2.85×10 6 cells/fish for 7 d and RPS (%) was calculated. Specific cellular and humoral immune responses were determined for rohu of R1 and R2. Results showed that rohu immunized with outer membrane protein along with adjuvant could offer an appropriate vaccine strategy. Keywords: Aeromonas hydrophila, rohu, vaccine, specific immune response 1. Introduction Aquaculture apart from being a most promising sector, it provides high quality protein, generates income, employment and foreign exchange around the globe. Global fish production has reached to about 178.5 million tons with inland aquaculture representing 28.73% of total production (FAO) [11] . In India, freshwater fish culture practices mainly constitute the culture of Indian major carps namely, catla (Catla catla), rohu (Labeo rohita) and mrigal (Cirrhinus mrigala). Carp culture constitutes more than 80% of total aquaculture production of India (Jaysankar) [14] out of which Labeo rohita commonly known as rohu, is most prominent among others due to its high growth potential coupled with high consumer preferences and high nutritive value. Like other freshwater fishes rohu can be infected by different pathogens, microorganisms or parasites. The bacterial infections are considered the major factors of mass mortality in farmed and wild fish. Aeromonas hydrophila is considered as most common bacterial pathogen in rohu, and has been considered as causative agent of several distinct pathological situations including swelling of tissues, necrosis, ulceration, tail/fin rot, motile aeromonas septicemia or haemorrhagic septicemia as a primary pathogen (Hu et al.) [13] , (Rasmussen et al.) [22] . During the past decades, a lot of efforts have been given for immunization of fish with the vaccines. It has been already established that the improvement of a suitable vaccine approach have successfully given protection to the teleost against different infectious diseases caused by pathogen (Uribe et al.) [32] , (Gudding and Muiswinkel) [12] , (Bøgwald and Dalmo) [4] . It is well known that fish are equipped with immunological properties and are quite able to raise competent protection against invading pathogens. Particularly a proper knowledge of acquired immune response in fish is urgently needed for the betterment of defensive strategies to combat against fish diseases in the aquaculture sector. Several attempts had been made by different scientist for immunization of rohu against Aeromonas hydrophila infection (Shoemaker et al.) [29] , (Dash et al.) [8] , (Bharadwaj et al.) [3] , (Sen et al.) [28] , (Dash et al.) [7] , (Dubey et al.) [9] . Till date many efforts have been made to develop vaccines throughout world, from inactivated products and live attenuated organisms to advancement high tech vaccines against A. hydrophila in different fish species (Mzula et al.) [19] but till now suitable