Abstract: Since sodium butyrate has been listed in the Catalogue of Feed Additives by the Ministry of Agriculture in 2006, its application and research work in domestic livestock production has been carried out in large areas. It has been found that sodium butyrate can partially replace antibiotics, and it plays a role in acidification, regulation of electrolyte balance, gastrointestinal micro-ecological balance, and attracting. As a new type of green additive, sodium butyrate has attracted people's attention and has broad application prospects in livestock production. At present, domestic research on the application of sodium butyrate in livestock production is mostly directed at young animals, and the application research on breeding sows is very lacking. In this paper, the application effect of sodium butyrate in breeding sows is reviewed, which provides new ideas for improving reproductive performance, reducing disease occurrence and reducing elimination. Key words: sodium butyrate; breeding sow 1 sodium butyrate in breeding sows 1.1 increase the rate of calcium absorption, extend the time of sow breeding Sodium butyrate can increase the absorption of calcium by animals. Guo Xiaohua et al (2004) found that the sodium butyrate group increased calcium absorption by 2% compared with the antibiotic group, and the sodium butyrate + antibiotic group increased by 8.8% compared with the antibiotic group. It has also been shown that sodium butyrate can increase the absorption rate of calcium in the intestines of breeding sows to 53%. There are several reasons for the absorption of calcium by sodium butyrate: on the one hand, sodium butyrate increases the height of the villi and the depth of the crypt, increasing the absorption area of ​​the nutrient in the small intestine, thereby enhancing the absorption of nutrients including calcium. Salminen et al. (1998) reported that sodium butyrate significantly increased the proliferation of stem cells, and increased the surface area in the intestine by increasing the proliferation of crypts and the length of the small intestine villi, particularly in the proximal and distal ileum. Galfi et al. (1990) found that the addition of sodium butyrate increased the length of jejunal microvilli and cecal crypt depth in growing pigs (241d). Luo Haixiang et al (2006) showed that 0.1% sodium butyrate significantly increased the ratio of duodenal and ileal villus height to crypt depth in the first week after weaning and decreased crypt depth (P<0.05). On the other hand, sodium butyrate can selectively inhibit the proliferation of Salmonella and Escherichia coli and promote the growth of beneficial bacteria such as Lactobacillus. Galfi et al. (1990) found that the addition of 0.17% sodium butyrate to the diet of weaned piglets reduced the number of E. coli in the ileum and increased the number of lactobacilli. Castillo et al. (2006) found that the addition of sodium butyrate to the diet of early weaned piglets did not change the total number of microbes in the gastrointestinal tract and increased the proportion of lactobacilli in intestinal bacteria. An increase in the number of beneficial bacteria such as lactobacilli can produce more lactic acid and butyric acid products. Galfi et al. (1991) found that the addition of sodium butyrate to the feed increased the content of butyric acid compared with the control group: 0.94mmol/L in the stomach, 0.49mmol/L in the jejunum, 0.47mmol/L in the cecum, and increased in the stomach: 4.08mmol/ L, jejunum 15.29mmol / L, ileum 86.15mmol / L, cecal 11.49mmol / L. Lactic acid and butyric acid reduce the pH value in the hindgut of the intestine, acidify, fully dissolve the calcium salt, and improve the absorption and utilization of calcium. Lactic acid also forms complexes with calcium, further increasing calcium absorption. In addition, sodium butyrate may affect the effective translation of mRNA by affecting the amount of mRNA on the cell membrane, and achieve the regulation of calcium transporter gene expression to affect the absorption of calcium. The full absorption of calcium improves the contractility of uterine smooth muscle, which can make sows yield and reduce dystocia. At the same time, it prevents excessive loss of calcium in sow bones, reduces the occurrence of sow leg disease, and prolongs the breeding period. 1.2 promote hemoglobin synthesis, improve blood oxygen carrying capacity Sodium butyrate can promote the synthesis of blood hemoglobin in sows and increase the number of red blood cells. Liu Zhijie et al (2001) showed that butyrate can induce globin gene expression and promote hemoglobin synthesis, especially to selectively stimulate the synthesis of fetal hemoglobin. Li Jinying et al (2002) pointed out that butyrate induced the Y gene distal promoter, significantly inhibited the hemoglobin conversion process, increased the non-a chain / a chain ratio, and stimulated HbF synthesis. The number of red blood cells is increased, the oxygen carrying capacity of the blood is enhanced, the sow skin is bright red, the embryos have difficulty in breathing in the late pregnancy, and the rate of white piglets is reduced. At the same time, the oxygen carrying capacity of cord blood is enhanced to improve the ability of embryo implantation. The newborn piglets are red and bright, and their vitality is strong. 1.3 increase milk production, increase milk fat rate Lactating sows must increase their feed intake in order to maximize nutritional satisfaction and maintain energy needs such as lactation. Sodium butyrate has a specific fat odor and has an olfactory stimulation and attracting effect on sows, which can increase feed intake of sows, especially in early lactation, thereby increasing milk production. Tokach et al. (1992) and Koketsn et al. (1996) suggested that nutrient deficiencies in early lactation have an effect on sow milk production and have a lasting effect on the reproductive performance of sows after weaning. Sodium butyrate stimulates the secretion of cholecystokinin (CCK hormone), activates the activity of digestive enzymes (such as pancreatic amylase and pancreatic lipase), and improves feed digestibility. Sodium butyrate can promote the production of insulin, stimulate the secretion of pancreatic hormone, increase the levels of glucagon and insulin, and further stimulate the formation of colonic epithelial cells. Pancreatic digestive enzyme levels are also increased, and lactose, maltose, and sucrose concentrations in the intestinal lumen are greatly increased (Sano et al., 1995). Sodium butyrate provides energy for physiological activities such as digestion and absorption of epithelial cells, and comprehensively improves the ability of the intestine to digest and absorb nutrients in feed. Salminen et al (1998), Salminen et al (1998), Galfi et al (1990), Luo Haixiang et al (2006) showed that sodium butyrate increased the digestive absorption area of ​​the small intestine by increasing the height of the intestine villi and the depth of the crypt. Absorption of nutrients. Guo Xiaohua et al. (2004) found that the absorption rate of energy in the sodium butyrate group was 2.34% higher than that in the antibiotic group, and the antibiotic and sodium butyrate group was 3.65% higher than the antibiotic group. An East Asia et al. (2007) studied the effects of yeast β-1,3,1,6-glucose and sodium butyrate on the growth performance and physiological metabolism of weaned piglets. It was found that sodium butyrate can significantly increase the 56-day-old piglets. Serum triglyceride and fatty acid concentration (p<0.05), indicating that sodium butyrate can promote the absorption of short-chain fatty acids, accelerate the synthesis of fat, and thus increase the content of serum triglycerides. Due to the increase in fat absorption rate of intestinal epithelial cells, the milk fat percentage in milk is increased. At the same time, short-chain fatty acids can stimulate the proliferation and development of breast cells and promote the formation and secretion of milk. 1.4 promote immune cell proliferation, improve the health of sows Intestinal mucosal immune cells include lymphocytes, goblet cells, and mast cells, as well as plasma cells and phagocytic cells. Sodium butyrate can promote the division and proliferation of goblet cells, intraepithelial lymphocytes and mast cells in intestinal epithelial cells. Wang Jifeng et al (2005) showed that the number of lymphocytes and mast cells in the intestinal epithelial cells of the sodium butyrate group was significantly better than that of the control group, and the lymphocytes and mast cells in the jejunal epithelial cells increased to 40.2±7/100 columns, respectively. For epithelial cells and 1797/intestinal sections, the corresponding changes in the ileum were 32.1 ± 5.7 cells per 100 columnar cells and 636 per intestinal sections. At the same time, the number of goblet cells in the sodium butyrate group was 6.7 ± 2.4 / 100 columnar epithelial cells (jejunum) or 9.2 ± 4.1 cells / 100 columnar epithelial cells (ileum), significantly higher than the antibiotic group 3.9 ± 2.3 / 100 columnar epithelial cells (jejunum) or 6.5 ± 2.6 cells/100 columnar epithelial cells (ileum). Li Fuyan et al (2006) found in broiler chicken that sodium butyrate significantly increased the number of mast cells in the duodenum, jejunum and ileum, which increased by 19.7%, 27.2% and 30.7%, respectively, compared with the control group. Increased activity of lymphocytes, goblet cells and mast cells in the intestinal mucosa, enhanced activity of plasma cells and phagocytic cells, thereby enhancing the sensitivity of the immune response of the gastrointestinal immune system, improving the body's immunity, and synergizing healthy and intact intestinal epithelium and The structure of the intestinal wall creates a strong immune barrier to the gastrointestinal tract. 1.5 Maintaining the internal environment balance and enhancing the heat stress resistance Sodium butyrate dissociates into butyrate and sodium ions in animals. The final metabolites of butyrate are ketone bodies and carbon dioxide (CO2). When the intestinal mucosa metabolizes a large amount of energy, the amount of intracellular ATP synthesis increases, causing the CO2 concentration to increase, which stimulates the carbonic anhydrase activity in the body, and converts the produced CO2 into HCO3-, resulting in an increase in the body's H+ concentration. Exchange with Na+. As a result, Na+ absorption increases, water absorption increases, maintains a stable internal environment, and enhances the ability of sows to resist heat stress. 1.6 through the milk into the piglets, reduce the occurrence of gastrointestinal tract disease in piglets Sodium butyrate can be used by piglets through the sow's mammary gland tissue, and the milk dry matter contains about 3.8% of butyric acid derivatives. Sodium butyrate can reach the piglets through milk, promote the development and maturation of the gastrointestinal tract of piglets, maintain the health of the intestines, and reduce the occurrence of yellow, white diarrhea and diarrhea in piglets. 2 Conclusion Due to the long-term abuse of antibiotics, the drug resistance is serious. Antibiotics are very unsatisfactory in the treatment of various diseases of pigs. Excessive overdose is harmful to the health and production performance of sows. People are beginning to realize the importance of pig health to the farm. Nutritional immunity has become the first consideration for farmers. Sodium butyrate is an energy source for gastrointestinal epithelial cells, a repair agent for mucosal epithelium, and an immunopotentiator for mucosal immune system, providing a new way for people to control high fever in pigs. However, the mechanism and effect of sodium butyrate in breeding sows need to do more in-depth and meticulous research work. Medium Duty Mini Casters,Medium Pvc Caster,Mini Pvc Caster,Pvc Wheel BENYU CASTERS & WHEELS CO.,LTD , https://www.benyucaster.com