Examination of the ability of the Antarctic fish Pagothenia borchgrevinki to withstand hypoxic conditions, their ability to recover and the potential for lactate as an end product of metabolism during hypoxia

Fish muscle was not found to produce lactic acid as an end product of anaerobic metabolism during high speed swimming. However, analysis of the enzymes involved in anaerobic metabolism, particularly LDH suggest that the muscle have the ability to produce it. This study investigated if perhaps lactic acid is essential for survival during hypoxia (low oxygen levels) if it’s not produced during swimming. Fish were placed in closed box respirometers and their oxygen consumption was monitored until they became severely hypoxic. At this point the respirometers were reoxygenated and any increase in oxygen consumption needed to repay an oxygen debt was monitored. Tissue was collected for analysis of lactate.