Interactive effects of food deprivation state and hypoxia on the respiratory responses of postprandial rock crabs, Cancer irroratus

AbstractUnder the background of climate change, increasing attention has focused on the effects of ocean deoxygenation on marine organisms. However, few studies address the effects of different food deprivation states on hypoxia tolerance. We therefore investigated the metabolic responses of the Atlantic rock crab,Cancer irroratus (starved 28 –35 days, fasted 3–5 days and recently fed). Starved-crab exhibited the lowest critical oxygen saturation (Scrit), while fed-crab had the highestScrit. The fed-crab maintained an elevated postprandial oxygen consumption (MO2) even below theScrit of fasted-crab indicating reserved aerobic scopes for critical activities in severe hypoxia. Following feeding, hypoxia (50% and 20% oxygen saturation,SO2) retarded the specific dynamic action resulting in lower peak MO2 and longer duration. The starved-crab exhibited a lower peak MO2, prolonged duration and higher energy expenditure than fasted-crab after feeding. The decline in arterialPO2 was most pronounced below theScrit for both fasted- and starved-crab. The higher hemocyanin concentration ([Hc]) of fasted-crab (than starved-crab) suggested they had improved oxygen transport capacity, but hypoxia did not increase [Hc] during the 72-h experiment. Following feeding, the fasted-crab significantly increasedl-lactate concentration ([l-lactate]) in 20%SO2, which was not observed in starved-crab. These results suggest starvation may trigger a cross-tolerance to hypoxia. Because crabs can under...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - Category: Physiology Source Type: research