Resumen del producto

In marine ectotherms, reproduction is an energetically expensive process that affects their thermalwindow tolerance. For most species, the impacts of hyperthermia during gametogenesis have stillnot been addressed. Our aim was to assess the metabolic response of adult Nodipecten subnodosusscallops to thermal challenges at early development (spring) and advanced gonad maturation(summer). Scallops collected in both seasons were exposed to acute hyperthermia (26 and 30 °C, 24 h),maintaining a group of scallops at acclimation temperature (22 °C) as a control condition. During thesummer, relatively low activity of hexokinase (HK), as well as low levels of ATP and GTP were foundin the adductor muscle, suggesting a shift in energy investment for reproduction, although argininephosphate (ArgP) levels were higher in summer scallops. Hyperthermia (30 °C) induced an increasedenergy expenditure reflected by a transitory enhanced oxygen consumption (VO2) and relativelyhigh activities of HK and arginine kinase (AK). Moreover, a slight decrease in adenylic energy charge(AEC) was partially compensated by a decrease in ArgP. An increase in nucleotide by-products inosinemonophosphate (IMP) and hypoxanthine (HX) indicated a thermal stress at 30 °C. Some of theresponses to acute hyperthermia were more pronounced at advanced maturation stages (summerscallops), indicating a possible lack of energy balance, with possible implications in animals challengedto global warming scenario.

Palabras clave: ectotherms; thermal challenges

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