Fiber type and metabolic characteristics of lion (Panthera leo), caracal (Caracal caracal) and human skeletal muscle

Abstract

Lion (Panthera leo) and caracal (Caracal caracal) skeletal muscle samples from Vastus lateralis, Longissimus dorsi and Bluteus medius were analysed for fiber type and citrate synthase (CS; EC 2.3.3.1), 3-hydroxyacyl Co A dehydrogenase (3HAD; EC 1.1.1.35(, phosphofructokinase-1 (PFK; EC 2.7.1.11), creatine kinase (CK; EC 2.7.3.2), phosphorylase (PHOS; EC 2.4.1.1) and lactate dehydrogenase (LDH; EC 1.1.1.27) activities and compared to human runners, the latter also serving as validation of methodology. Both felids had predominantly type IIX fibers (range 50-80%), whereas human muscle had more types I and IIs. Oxidative capacity of both felids (CS: 5-9 µmol/min/g ww) was lower than humans, whereas the glycolytic capacity was elevated. LDH activity of caracal (346±81) was higher than lion (277±62 µmol/min/g ww), with human being the lowest (55±17). CK and PHOS activities were also higher in caracal and lion compared to human, but PFK was lower in both felid species. The current data and past research are illustrated graphically showing a strong relationship between type II fibers and sprinting ability in various species. These data on caracal and lion muscles confirm their sprinting behaviour.