Abstract: As an essential nutrient,selenium plays important role in antioxidation,immunity and antitumor.Selenium deficiency in the body can cause diseases such as skeletal muscle degeneration or necrosis,liver necrosis and myocardial fibrosis.Therefore,it has been paid more and more attention in human and animal nutrition.As a kind of organic selenium,selenomethionine (Se-Met) has higher bioavailability and lower toxicity than sodium selenite,and it is an effective organic selenium source to replace inorganic selenium.In response to the current demand for selenium sources in animal production,this article takes Se-Met as the research object,introduces the absorption and metabolism mechanism of Se-Met in the body,and on this basis,makes a comparative analysis with inorganic selenium,highlighting the advantages of Se-Met as an organic selenium supplement.The function and mechanism of Se-Met in the body's antioxidation,immunity and antitumor,and the effect of its application in animal production are briefly described.The application status of Se-Met in pig production is explained,and through the analysis of growth indicators such as daily weight gain,daily feed intake,and feed-to-weight ratio,as well as meat quality indicators such as pH,drip loss,selenium deposition,and meat color of pork,the possibility of Se-Met being widely used in animal production is further determined.This article aims to provide practical reference and theoretical basis for the widespread replacement of inorganic selenium by organic selenium such as Se-Met in animal nutrition in the future,and provide references for subsequent scientific research.

Key words: selenomethionine; absorption and metabolism; biological function; pig production