The glucose and lactate kinetics of American eels, <i>Anguilla rostrata</i> (LeSueur), under MS 222 anaesthesia

Abstract

Glucose and lactate kinetics were examined in fed and food‐deprived American eels, Anguilla rostrata (LeSueur), under MS 222 anaesthesia (AE). These values are compared to free‐swimming, non‐anaesthetized animals (FSE) reported previously (Cornish &amp; Moon, 1985). The AE group demonstrated a steady but minor hyperglycemia during the 5‐h experiment and significant decreases in both glucose turnover and metabolic clearance rates compared to the FSE groups. Food‐deprivation further depressed these kinetic parameters. Blood lactate continuously increased during the experiment, reaching values 300 times (fed) and 100 times (food‐deprived) higher than the similar FSE groups. Consistent with these higher concentrations, rates of lactate appearance in and disappearance from the blood generally increased with anaesthesia. This study supports the view of Soivio et at. (1977) that MS 222 acts as an asphyxiant. The associated metabolic disruptions are consistent with a reduction in oxidative in favour of anaerobic tissue metabolism. The specific changes in glucose and lactate parameters reflect the nervous and hormonal disruptions occurring with anaesthesia. These studies urge caution in the interpretation of data using an anaesthetized fish preparation.