Selenium is one of the essential micronutrients in humans and animals. It is the active component of glutathione peroxidase in animals. It has the functions of improving immunity, protecting liver and anti-aging. It is an essential nutrient for the human body. About 72% of China's regions have low selenium or selenium deficiency, and the content of selenium in feed and pasture in more than 2/3 areas is less than 0.05 mg/kg, which cannot meet the normal physiological needs of animals. Therefore, selenium supplementation in feed has become a necessary measure. Selenium compounds are divided into two major categories: organic selenium and inorganic selenium. Organic selenium has high biological activity, can be assimilated in vivo, is less toxic than inorganic selenium, and is beneficial for absorption in organisms. It is an ideal trace element. Nutrition supplements. Selenium yeast is a fermented product that converts inorganic selenium into organic selenium by using yeast as a carrier. Yeast cells can convert inorganic selenium into organic macromolecules in cells during fermentation, resulting in high biological activity and low toxicity. Organic selenium is absorbed by the body 20 times that of inorganic selenium [1]. Since China is a country lacking selenium, and selenium obtained from natural foods is difficult to meet the demand for selenium, selenium-enriched yeast has great potential as a safe and effective source of selenium. 1 The physiological function of selenium-enriched yeast At present, selenium-enriched yeast has been widely used in animal feed, and its main physiological functions are reflected in the following aspects: 1.1 Antioxidant effect Selenium is a cofactor for various peroxidases in animals, which activates the antioxidant activity of cells and has a direct impact on the sperm activity of male animals and the conception of sows. Selenium is a component of glutathione peroxidase and niacin hydroxylase involved in the synthesis of coenzyme Q and coenzyme A, and is also a component of cytochrome associated with electron transport. Glutathione peroxidase protects the structure and function of cell membranes by catalyzing redox reactions, enhancing the antioxidant effects of vitamin E and eliminating free radicals. 1.2 Enhance immunity, improve disease resistance and anti-stress ability Liu Zongping reported that selenium can affect the immune function of the body in many ways [2]. Selenium can effectively improve the body's humoral immunity and cellular immunity. Studies on cellular immune function have shown that selenium supplementation can significantly enhance the activity of human and animal killer T cells and NK cells. 1.3 Improve animal production performance, promote animal growth and development, and improve feed utilization. 1.4 Improve fertility There is a reproductive disorder in selenium deficiency in animals, mainly due to the imbalance of endocrine secretion of reproductive hormones. For the mother, selenium supplementation can prevent maternal abortion and reduce embryonic death. It can improve the laying rate and egg quality of laying hens, prolong the laying period and peak period, and improve feather traits. 1.5 improve the quality of meat, improve the rate of lean meat The anti-oxidation effect of selenium makes it simultaneously improve the quality of livestock and poultry meat products. Selenium can prevent the occurrence of lipid peroxidation through GSH-Px, protect the integrity and function of cell membrane structure, and reduce cell damage. Prevent the outflow of muscle cell fluid, reduce the amount of muscle exudation juice, and improve the quality of livestock and poultry meat. Carbide Drill Bits,Tungsten Carbide Center Drill Bit,Carbide Center Drills Bit,Carbide Spot Drill Bit Supal(changzhou)Precision Tools Co.,Ltd , https://www.endmillpro.com