White Muscle Disease
Also known as Stiff lamb disease, characterised by myodegeneration. Disease is stress induced so the breakdown of muscle relies on increased muscle activity. Muscle degenerates due to a failure to control the free radicals produced by its metabolism upon contraction. Free radicals damage cellular membranes and proteins.
Muscle damage allows the release of:
- Potassium: can lead to heart failure.
- Myoglobin: can lead to renal failure.
- Creatine Kinase: useful to measure muscle damage.
Grossly the damaged muscle will contain white streaks.
The damage caused by Zenker degeneration is reversible if the sarcolemma remains intact.
- Very important economic disease of sheep, cattle and pig
- Caused by:
- Deficiency of selenium, vitamin E or both
- Exacerbated by rapid growth, unaccustomed exercise or other dietary factor
- Oxygen free radicals (OFR) can damage cell membranes
- Vitamin E usually mops up OFRs
- Selenium as part of glutathione peroxidase neutralises effects of OFRs
- If Vit E or Se are deficient -> the balance shifts to membrane damage, calcium entry and mitochondrial damage -> cell swells and dies -> segmental muscle necrosis