The enhancement of resistance of the American eel, Anguilla rostrata Le Sueur, to a pathogenic bacterium, Aeromonas hydrophila, by an extract of the tunicate, Ecteinascidia turbinata

Abstract. Extracts of the tunicate Ecteinascidia turbinate were used in preventing Aeromono hydrophila infection in the American eel, Anguilla rostrata. Intraperitoneal injection of the extract 2 days after bacterial challenge was shown to increase dramatically eel phagocytic activity and resistance to disease. Intravenous injection of the extract 2 days post-bacterial injection was shown to increase antibody titres. This study helps to substantiate the possible use of E. turbinata extract in treating eel diseases. The exact nature of its protective effect will be dependent on the time and route of its delivery.