Enzymatic digestive activity and absorption efficiency in Tagelus dombeii upon Alexandrium catenella exposure
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ORIGINAL ARTICLE
Enzymatic digestive activity and absorption efficiency in Tagelus dombeii upon Alexandrium catenella exposure M. J. Ferna´ndez-Reiriz • J. M. Navarro B. A. Cisternas • J. M. F. Babarro • U. Labarta
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Received: 27 January 2012 / Revised: 4 March 2013 / Accepted: 5 March 2013 Ó Springer-Verlag Berlin Heidelberg and AWI 2013
Abstract We analyzed absorption efficiency (AE) and digestive enzyme activity (amylase, cellulase complex, and laminarinase) of the infaunal bivalve Tagelus dombeii originating from two geographic sites, Corral-Valdivia and Melinka-Ayse´n, which have different long-term paralytic shellfish poisoning (PSP) exposure rates. We report the effects of past feeding history (origin) on T. dombeii exposed to a mixed diet containing the toxic dinoflagellate Alexandrium catenella and another dinoflagellate-free control diet over a 12-day period in the laboratory. Absorption efficiency values of T. dombeii individuals that experienced PSP exposure in their habitat (Melinka-Ayse´n) remained unchanged during exposure to toxic food in the laboratory. In contrast, T. dombeii from a non-PSP exposure field site (Corral-Valdivia) showed a significant reduction in AE with toxic exposure time. This study established that the amylase and cellulase complexes were the most important enzymes in the digestive glands of Tagelus from both sites. The temporal evolution of enzymatic activity under toxic diet was fitted to exponential (amylase and cellulase) and to a logarithmic (laminarinase) models. In all fits, we found significant effect of origin in the model parameters. At the beginning of the experiment,
Communicated by H.-D. Franke. M. J. Ferna´ndez-Reiriz (&) J. M. F. Babarro U. Labarta Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Cientı´ficas, Eduardo Cabello 6, 36208 Vigo, Spain e-mail: [email protected] J. M. Navarro B. A. Cisternas Facultad de Ciencias, Instituto de Ciencias Marinas y Limnolo´gicas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
higher enzymatic activity was observed for clams from Corral-Valdivia. The amylase activity decreased with time exposure for individuals from Corral and increased for individuals from Melinka. Cellulase activity did not vary over time for clams from Corral, but increased for individuals from Melinka and laminarinase activity decreased over time for individuals from Corral and remained unchanged over time for Melinka. A feeding history of exposure to the dinoflagellate A. catenella was reflected in the digestive responses of both T. dombeii populations. Keywords Alexandrium Tagelus dombeii Absorption efficiency Enzymatic activity Trophic regimen
Introduction Tagelus dombeii (razor clam) is an infaunal species that inhabits soft sediments at a water depth of 1–13 m between the Tumbes region of northwestern Peru´ and Ayse´n in the southern Chile. Dense razor clam populations are farmed by traditional fisheries, and total landings have decreased from 7,294 t in 1995 to 3,248 t in 2010 (SERNAPESCA
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