Abstract:

Oxygen is the material basis for maintaining the metabolic homeostasis of mammals. If the oxygen supply is insufficient during the metabolic process,it can cause hypoxic stress. Environmental hypoxia,metabolic hypoxia,and oxygen-carrier dysfunction are known as the key causes of hypoxic stress. The impact of hypoxia on the body metabolism and tissue function of mammals were mainly conducted in lung,liver,digestive tract,muscle,and mammary gland,etc. It can maintain its metabolic homeostasis if a mammal in a hypoxic state has developed a metabolic pattern adapted to hypoxia. On the contrary,if the animal cannot maintain metabolic homeostasis under hypoxic conditions,it will cause oxidative stress or even pathological changes. At present,the research on hypoxic stress in livestock mainly focuses on the metabolic adaptation mechanism of plateau animals;however,the metabolic rate,oxygen consumption and free radical levels of lactating animals are relatively high,but the role of oxygen in the formation of metabolic stress in lactating animals and impact on lactation performance are still under being explored. The current review summarized the causes and consequences of hypoxic stress,aimed to discuss the biological basis of mammalian hypoxic stress,and to provide a theoretical basis for maintaining the health status of lactating animals from the perspective of hypoxic stress.

Key words: mammalian animals, hypoxic stress, oxygen, metabolic homeostasis, oxidative stress.