ORIGINAL PAPER Biochemical profile of Biomphalaria glabrata (Mollusca: Gastropoda) after infection by Echinostoma paraensei (Trematoda: Echinostomatidae) Victor M. Tunholi & Danilo Lustrino & Vinícius M. Tunholi-Alves & Clélia C. C. Mello-Silva & Arnaldo Maldonado Jr. & Jairo Pinheiro & Maria de Lurdes de A. Rodrigues Received: 5 July 2010 /Accepted: 2 March 2011 # Springer-Verlag 2011 Abstract The effect of infection by Echinostoma paraensei on the activity of the enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the concentration of total proteins, uric acid and urea in the hemolymph of Biomphalaria glabrata were investigated after exposure to five or 50 miracidia. The biochemical concentrations were measured weekly until the end of the fourth week after exposure. There was a significant decrease in the concentrations of total proteins in the snails exposed both to five and 50 miracidia, as well as an increase in the nitrogenous products of excretion, ALT and AST activities. The higher ALT activity in the hemolymph of the snails after infection with 50 miracidia suggests highest energetic requirement in these snails in relation to snails exposed to five miracidia. The results also suggest an increase in the use of total proteins, since there was increased formation of nitrogenous catabolites, in conformity with an increase in the aminotransferase activities, frequently associated with tissue damages. This can be explained by damage due to penetration by the miracidia and subsequent development of intramolluscan sporocysts and rediae. Introduction Echinostoma paraensei is a trematode species that can infect snails of genera Biomphalaria, Physa, and Lymnaea (Maldonado et al. 2001a). It was first described in naturally infected specimens of Biomphalaria glabrata (Lie and Basch 1967). Subsequently this trematode was isolated from its natural host, the wild rodent Nectomys squamipes (Maldonado et al. 2001b). Both B. glabrata and N. squamipes are natural hosts of Schistosoma mansoni (Maldonado et al. 2001c, 2006). During its intramolluscan development, E. paraensei presents both sporocyst and redia stages that migrate through the host snail’ s tissues, causing tissue destruction, and impairing its metabolic processes (Fried et al. 2004; Pinheiro et al. 2004a). Infection by trematodes can change the biochemical characteristics of the hemolymph of snails (Perez et al. 1994; Bandstra et al. 2006). The higher energy demand resulting from infection by trematodes results in redirection of the metabolic routes, such as that of the proteins. When infected by parasites, snails drastically increase their mobilization of carbohydrates. The glucose concentration in the hemolymph is severely reduced and the snails resort to their reserves from the digestive gland and cephalopedal mass. This has been shown to be related to the intoxication caused by the increase in nitrogenous products of excretion (Pinheiro and Amato 1994, 1995). This mobilization V. M. Tunholi : D. Lustrino : V. M. Tunholi-Alves : J. Pinheiro (*) Área de Biofísica, Departamento de Ciências Fisiológicas, Instituto de Biologia, UFRuralRJ, Rio de Janeiro, Brazil e-mail: jps@ufrrj.br V. M. Tunholi : V. M. Tunholi-Alves : M. A. Rodrigues Curso de Pós-Graduação em Ciências Veterinárias, Departamento de Parasitologia Animal, Instituto de Veterinária, UFRuralRJ, Rio de Janeiro, Brazil C. C. C. Mello-Silva Laboratório de Esquistossomose Experimental, Instituto Oswaldo Cruz, Fiocruz, RJ, Rio de Janeiro, Brazil A. Maldonado Jr. Laboratório de Biologia e Parasitologia de Mamíferos Silvestres Reservatórios, Instituto Oswaldo Cruz, Fiocruz, RJ, Rio de Janeiro, Brazil Parasitol Res DOI 10.1007/s00436-011-2330-7