The metabolic profile of cardiac and skeletal muscle tissue from captive emus (Dromaius novaehollandiae) raised in northern Colorado: implications for assessing muscle health for emus with splayed-leg disorder

Green, Todd L., author
Kanatous, Shane B., advisor
Ghalambor, Cameron K., committee member
Pitcaithley, Sandra L., committee member
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Emus (Dromaius novaehollandiae) are native Australian flightless birds commonly farmed in North America for oil and meat. The emu industry has grown in popularity, though the physiology of farm-raised emus has not been studied extensively. Emus are efficient at both anaerobic sprinting and aerobic, sustained running, though it is unclear if they are inherently predisposed to be terrestrial athletes. Though some wild emu energetic studies have been completed, few studies have been performed on domesticated emu skeletal muscle, and there have been no investigations into the enzymatic profile of domesticated ratite (group of paleognathous flightless birds that includes emus) cardiac tissue. This thesis established the first ratite cardiac metabolic profile by determining the myoglobin concentration (3.41 ± 0.06 mg g-1 wet tissue) and activities of citrate synthase (CS 19.4 ± 1.2 µmol min-1 g-1 wet tissue), β-hydroxyacyl CoA dehydrogenase (HAD 78.9 ± 3.6 µmol min-1 g-1 wet tissue), and lactate dehydrogenase (LDH 239.5 ± 8.9 µmol min-1 g-1 wet tissue) of domesticated emu cardiac tissue. Emus had ~22% higher myoglobin levels in cardiac tissue compared to domesticated chickens, and ~89% higher than domesticated dogs. The metabolic potential of emu cardiac tissue appeared more similar to that of active flying birds, such as pigeons and geese. Enzymatic characteristics of the heart illustrate domesticated emus can be metabolically categorized with other animals classified as elite avian and mammalian athletes. This study also sets a metabolic baseline for three pelvic limb skeletal muscles (control limb): M. gastrocnemius medialis (GM) - myoglobin 2.74 ± 0.03 mg g-1 wet tissue, citrate synthase (CS) 12.14 ± 1.21 µmol min-1 g-1 wet tissue, β-hydroxyacyl CoA dehydrogenase (HAD) 14.05 ± 0.52 µmol min-1 g-1 wet tissue, lactate dehydrogenase (LDH) 905.44 ± 67.58 µmol min-1 g-1 wet tissue; M. iliofibularis (IFB) - myoglobin 3.04 ± 0.08 mg g-1 wet tissue, CS 18.43 ± 0.85 µmol min-1 g-1 wet tissue, HAD 23.04 ± 2.28 µmol min-1 g-1 wet tissue, LDH 913.08 ± 57.92 µmol min-1 g-1 wet tissue; M. iliofemoralis externus (IFME) - myoglobin 4.43 ± 0.07 mg g-1 wet tissue, CS 18.23 ± 0.40 µmol min-1 g-1 wet tissue, HAD 28.66 ± 0.91 µmol min-1 g-1 wet tissue, LDH 947.65 ± 37.70 µmol min-1 g-1 wet tissue. Additionally, for future studies on ratite orthopedic disorders, metabolic profiles of three pelvic muscles from both limbs (splayed limb and non-splayed limb) of emus affected by splayed-leg disorder were recorded. In general, both limbs of the splayed-leg emus had higher levels of metabolic proteins, and therefore looked more athletic than the control limbs. Though these emus had an orthopedic disorder, it was found their muscles increased in aerobic capacity, as evidenced by enhanced enzyme activities and myoglobin levels to offset the additional workload caused by the disorder.
2012 Spring.
Includes bibliographical references.
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cardiac muscle
Dromaius novaehollandiae
skeletal muscle
splayed-leg disorder
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