Abstract: In order to investigate the effects of oxygen providing on breeding eggs hatching efficacy of Lhasa white chickens and Tibetan chickens, the breeding eggs of the fifth generation of Lhasa white chickens, Nimu Tibetan chickens and Shannan Tibetan chickens were selected to perform a hatching trial, and the indicators associated with hatching efficacy of the breeding eggs of different chicken varieties during and at the end of the hatching process were determined and compared. The results showed that higher egg wight, birth weight and the ratio of birth weight to hatched egg weight was observed in Lhasa white chickens and Nimu Tibetan chickens under the oxygen non-providing condition compared to the oxygen providing condition, however, the opposite results were observed in Shannan Tibetan chickens. When oxygen was provided, the hatching rate of incubated eggs of Lhasa white chickens, Nimu Tibetan chickens and Shannan Tibetan chickens were 29.40%, 35.01% and 14.72% higher than those under the oxygen non-providing condition. Under the oxygen providing condition, the hatching rate of fertilized eggs of Lhasa white chickens, Nimu Tibetan chickens and Shannan Tibetan chickens were 31.55%, 39.49% and 11.91% higher than those when oxygen providing was absent. In conclusion, hypoxia is the most important factor that limits the improvement of hatching rate of breeding eggs of elite germplasm resources of chickens in plateau. Our results may provide a theoretical reference for improving the hatching rate of breeding eggs under plateau condition.

Key words: oxygen providing, Lhasa white chickens, Tibetan chickens, breeding eggs, hatching rate, plateau