World Journal of Fish and Marine Sciences 1 (4): 278-282, 2009 ISSN 1992-0083 © IDOSI Publications, 2009 Corresponding Author: J. Selvin, Department of Microbiology, Bharathidasan University, Tiruchirappalli 620 024, India 278 In vivo Antiviral Activity of Polysaccharide from the Indian Green Alga, Acrosiphonia orientalis (J. Agardh): Potential Implication in Shrimp Disease Management A. Manilal, S. Sujith, J. Selvin, G. Seghal Kiran and C. Shakir 1 1 1 2 1 Department of Microbiology, Bharathidasan University, Tiruchirappalli 620 024, India 1 Department of Biotechnology, Bharathidasan University, Tiruchirappalli 620 024, India 2 Abstract: The polysaccharide extracted from the marine green algae, Acrosiphonia orientalis was evaluated for in vivo antiviral activity against the shrimp pathogen, White Spot Syndrome Virus (WSSV). The algal polysaccharide was rationalized with commercial shrimp feed and orally administrated for a period of 14 days followed by the artificial viral challenge experiment. It was found that shrimp fed medicated diet (4g/kg) exhibited better survival rate (88%) over the control (0%). The immune defence factors such as total haemoycte count, differential haemocyte count and phenoloxidase activity was high for shrimp treated with algal polysaccharide. Therefore, it was concluded that the algal polysaccharide can be utilized as prophylactic drug for the management of WSSV. Key words: Acrosiphonia orientalis % Algal polysaccharide % Antiviral activity % Immunostimulant %Haemocyte %Penaeus monodon INTRODUCTION non-specific defence mechanisms [2]. Application of Shrimp aquaculture is an economically important management is a recently developed ecofriendly approach industry, with high international trade value. During the [3]. Many researchers have demonstrated the use of past decade, non scientific shrimp farm intensification and natural polysaccharide to boost up shrimp immunity [3, 4]. improper management strategies have increased the Research pertaining to the immune enhancing mechanism incidence of infectious diseases which in turn declined in shrimp using the marine algal polysaccharide against the growth of this industry. Viral infections are recognized viral diseases is already reported [5]. as the principle threatening factor for sustainable shrimp It has been reported that the seaweeds from the farming. Throughout the world, more than 20 viruses Indian coast are wealthy resource of bioactive have been identified to cause shrimp diseases [1]. compounds [6]. Some of these seaweeds have already Among these, WSSV is recognized as the most dreadful been reported to possess antiviral potency [7]. Several pathogen causing 100% mortalities within a week of Indian seaweeds have been extensively used for the infection in hatcheries and growout conditions, causing ecofriendly management of shrimp diseases [3]. Therefore, tremendous economic loss. The WSSV, belonging to the the objective of the current study was to evaluate the family Nimaviridae (genus Whispovirus), has a wide in vivo antiviral property of A. orientalis and to examine host range. The clinical sign of the infection is the haemolymph parameters to determine the immune characterized by white spots on the exoskeleton and status of the shrimp. epidermis[1]. The sustainability of shrimp industry is now resort MATERIALS AND METHODS largely on prevention and control of diseases through proper farm management. It is well known that in Collection and Extraction of Polysaccharides from crustaceans, immunostimulants increase resistance to A. orientalis: A. orientalis was collected from the Kollam infectious diseases by enhancing both specific and natural immunostimulants for proactive shrimp disease coast (Southwest coast of India) and polysaccharides