Skeletal muscle damage following halothane anaesthesia in the domestic fowl: plasma biochemical responses

The effects of a short period (10 minutes) of halothane anaesthesia upon sk eletal muscle have been examined in broiler chickens. Integrity of the musc le membrane was assessed by measurement of plasma activities of intracellul ar enzymes. Creatine kinase activity was greatly increased during the first 12 hours post anaesthesia and remained elevated for at least 48 hours. Lac tate dehydrogenase activity exhibited a similar pattern which was less pron ounced. Halothane anaesthesia induced transient hypercapnic acidosis and hy pokalemia and increased corticosterone secretion but there was no significa nt effect upon deep body temperature. It is proposed that halothane may act directly upon skeletal muscle, perhaps influencing intracellular calcium h omeostasis, to alter membrane permeability and increase enzyme efflux refle cting a degree of post-anaesthetic muscle damage. The transient changes in electrolyte and acid-base balance may contribute to these effects. Precauti ons should be taken to minimise the incidence or extent of halothane induce d myopathy in birds particularly in rapidly growing broiler chickens where susceptibility may be increased.