title: Metabolic depression and whole-body response to enforced starvation by Crassostrea gigas postlarvae.
abstract: Physiological and biochemical measurements were performed on six oyster (Crassostrea gigas) cohorts, in order to: (a) investigate the whole-body response (growth, energy content, metabolic and excretion rates) of 2-week-old postlarvae (spat) to enforced (0-8 days) starvation, and (b) test the potential use of three aerobic enzyme systems as indices of physiological condition. Starvation resulted in exponential reduction of postlarval metabolic and excretion rates, as well as a linear decrease in enzyme activity. These response mechanisms effectively limited the loss of endogenous reserves after 2 days of starvation and maintained the oyster's functional integrity over prolonged (8 days) starvation. Proteins appeared to be selectively conserved during short-term (2 days) starvation, as suggested by a decrease in total protein content, while maintaining constant weight-specific enzyme activity. Postlarvae starved for 2 days exhibited relatively higher lipid losses, lower mortality and lower metabolism than metamorphosing stages, thus suggesting a greater buffering capacity to starvation in the former. The activity of the electron transport system may be a useful indicator of long-term stress or developmental condition of oyster postlarvae, while citrate synthase and cytochrome oxidase could be used as indicators of growth rate. None of these enzyme systems is recommended as an index of aerobic metabolism during short-term starvation.
authors.affiliation: Universidad Autónoma de Baja California, Instituto de Investigaciones Oceanológicas, Apdo. Postal 453, Ensenada, Baja California, Mexico. sgarcia@uabc.mx
authors.forename: Zaul
authors.initials: Z
authors.lastname: García-Esquivel
authors.forename: V Monica
authors.initials: VM
authors.lastname: Bricelj
authors.forename: Horst
authors.initials: H
authors.lastname: Felbeck
mesh_terms: D000818:Animals; D003576:Electron Transport Complex IV / Q000378:metabolism; D004734:Energy Metabolism; D007814:Larva / Q000378:metabolism* / Q000502:physiology; D010125:Ostreidae / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D013217:Starvation
chemical_list: D003576:Electron Transport Complex IV