AIMThe purpose of this experiment was to investigate the cardiac physiological characteristics for adaptation to high-altitude hypoxia in chickens.

METHODSTibetan, Dwarf Recessive White and Shouguang chickens were fed at low-and high-altitude, and measurements were made in heart weights, lactic acid (LA), lactate dehydrogenase (LDH), and succinate dehydrogenase (SDH) at the age of 10 weeks.

RESULTSThe results showed that Tibetan chickens at high-altitude had lower heart weight and LA content, and similar LDH activity, and higher SDH activity when compared to Dwarf Recessive White and Shouguang chickens.

CONCLUSIONIt was concluded that the cardiac mechanisms of high-altitude hypoxic adaptation in Tibetan chickens were increasing neither heart weight, nor level of anaerobic metabolism, but the higher SDH activity was significant to the adaptation. The SDH was a symbol enzyme for hypoxic adaptation in Tibetan chicken.