Glucose Uptake as an Alternative to Stop-Flow Respirometry for Measuring Metabolic Rate in Danio rerio Larvae

Abstract

Respirometry is the current gold-standard for measuring metabolic rate. However, there is a growing need for metabolic rate measurements suitable for developmental studies, particularly in Danio rerio, where many important developmental stages occur at < 4 mm. While many metabolic studies rely on respirometry, the cost and complexity of the equipment limits its appeal in non-specialist labs, and background respiration becomes increasingly problematic as the size of the organism reduces. Here, glucose uptake was compared to stop-flow respirometry as an alternative measure of metabolic rate more suitable to the small scale required for developmental studies. A Passing-Bablok regression revealed the rate of glucose uptake can be considered equivalent to oxygen consumption as a measure of metabolic rate in Danio rerio larvae within a 95% limit of agreement. Therefore, glucose uptake is a valid alternative to the gold-standard in small organisms where conventional respirometry is problematic. Summary statement The rate of glucose uptake is a valid alternative to respirometry for metabolic rate measurements in small larval fish.