Influence of molting and starvation on digestive enzyme activities and energy storage in Gammarus fossarum.
Among the many biological responses studied in ecotoxicology, energy-based biomarkers such as digestive enzyme activities and energy reserves appear to be useful predictive tools for detecting physiological disturbances in organisms. However, the use of these biological responses as biomarkers could be limited by the effects of confounding factors (biotic and abiotic) and physiological processes, such as the reproductive cycle. Thus, the optimal use of these biomarkers will be facilitated by understanding the effects of these factors on the energy metabolism of the sentinel species being studied. We considered abiotic factors (temperature and conductivity) in a previous study, whereas the present study investigated the effects of gender, the female reproductive stage, and food availability on the digestive enzyme activities and energy storage of Gammarus fossarum. The results indicated that, during the female reproductive cycle, the activities of digestive enzymes (amylase, cellulase, and trypsin) decreased significantly, whereas the levels of reserves (proteins, lipids, and sugar) increased until the last premolt stage. Restricted food diets only led to decreased amylase activities in both sexes. Food starvation also induced a decrease in the energy outcomes in females, whereas there were no effects in males. In general, the biochemical (digestive enzyme activities) and physiological (energy reserves) responses were more stable in males than in females. These results support the use of males fed ad libitum to limit the effects of confounding factors when using these energy biomarkers in Gammarus fossarum during biomonitoring programs.
Université Reims Champagne Ardenne, Unité Interactions Animal-Environnement, Reims, France.
Laetitia
L
Charron
Institut national de Recherche en sciences technologiques pour l'environnement et l'agriculture, Unité de Recherche Milieux Aquatiques, Ecologie et Pollutions (MAEP), Villeurbanne, France.
Olivier
O
Geffard
Institut national de Recherche en sciences technologiques pour l'environnement et l'agriculture, Unité de Recherche Milieux Aquatiques, Ecologie et Pollutions (MAEP), Villeurbanne, France.
Arnaud
A
Chaumot
Institut national de Recherche en sciences technologiques pour l'environnement et l'agriculture, Unité de Recherche Milieux Aquatiques, Ecologie et Pollutions (MAEP), Villeurbanne, France.
Romain
R
Coulaud
Université Reims Champagne Ardenne, Unité Interactions Animal-Environnement, Reims, France.
Ali
A
Jaffal
Université Reims Champagne Ardenne, Unité Interactions Animal-Environnement, Reims, France.
Véronique
V
Gaillet
Université Reims Champagne Ardenne, Unité Interactions Animal-Environnement, Reims, France.
Odile
O
Dedourge-Geffard
Université Reims Champagne Ardenne, Unité Interactions Animal-Environnement, Reims, France.
Alain
A
Geffard
D033304:Amphipoda / Q000201:enzymology / Q000502:physiology*; D000681:Amylases / Q000378:metabolism; D000818:Animals; D060829:Arthropod Proteins / Q000378:metabolism*; D002480:Cellulase / Q000378:metabolism; D004064:Digestive System / Q000201:enzymology; D004435:Eating; D004734:Energy Metabolism; D004784:Environmental Monitoring; D005260:Female; D008297:Male; D018978:Molting; D012098:Reproduction; D014357:Trypsin / Q000378:metabolism
D060829:Arthropod Proteins; D000681:Amylases; D002480:Cellulase; D014357:Trypsin