Biochemical Correlates of Swimming and Diving Behavior in the Little Penguin Eudyptula minor

Publisher Website
Google Scholar
Abstract
The extent to which the muscles powering swimming in the little penguin utilize aerobic and anaerobic metabolism was investigated by examining oxygen stores, muscle ultrastructure, the activities and properties of catabolic enzymes, and muscle buffering capacity. Blood hemoglobin and muscle myoglobin contents are high. Muscle cells contain many lipid droplets, little glycogen, and numerous large mitochondria. Maximum activities of rate-limiting glycolytic enzymes are not high relative to pectoralis muscle of short-burst type flyers. The pectoralis and supracoracoideus have a lower proportion of LDH M subunits and display greater pyruvate inhibition of LDH activity than these muscles of emperor and Adléie penguins. The maximum Krebs cycle flux may be lower than in birds capable of rapid sustained flight. The buffering capacities of the swimming muscles are lower than in emperor and Adélie penguins or in diving mammals. These results show that the muscles used to power swimming in the little penguin are basically aerobic with limited capacity for producing ATP during muscle anoxia. This suggests that these birds do not rely extensively upon short bursts of rapid swimming or indulge in prolonged deep diving to a point where oxygen stores available to the swimming muscles are exhausted.

This publication has 1 reference indexed in Scilit: