In early weaned piglets, the gastric acid secretion is insufficient, and the pH value of piglet feed is between 5.8 and 6.5. The pH value in the stomach of piglets is higher than the suitable activity range of pepsin, which affects the digestion and absorption of feed by piglets. Adding organic acids to piglet feed can improve the growth performance of piglets. Kirchgessner's test results show that the use of 1.5% to 2.0% fumaric acid can increase the average daily gain of piglets by 9%, feed intake by 5.2%, and feed utilization by 4.4%. Giesting et al. studied the effect of adding hydrochloric acid and sulfuric acid to the diet of weaned piglets. As a result, the feed intake of the test piglets decreased sharply, and the daily weight gain and feed utilization rate decreased seriously. This may be due to the influence of inorganic acid on the palatability and electrolyte balance of the feed. . 1. Slow down the speed of gastric emptying and promote digestion. The stimuli of gastric emptying rate are the volume and pH of the stomach contents. The acidic chyme enters the small intestine and stimulates the small intestine mucosa to secrete intestinal gastrin, which reflexively inhibits the peristalsis of the stomach and slows down the gastric emptying speed, so that the protein has more time to digest in the stomach. 2. Improve the gastrointestinal microflora The suitable pH values ​​for the growth of several pathogenic microorganisms are neutral alkaline. For example, the suitable pH value of Escherichia coli is 6.0-8.0, the staphylococcus is 6.0-7.5, and the staphylococcus is 6.8-7.5. The beneficial bacteria such as lactic acid bacteria are suitable in acidic environment. Growth and proliferation. Therefore, the acidifying agent can inhibit the proliferation of harmful microorganisms by reducing the pH of the gastrointestinal tract, and promote the proliferation of beneficial bacteria. Danielson et al. reported that lactic acid, a metabolite of lactic acid bacteria, can block the binding of E. coli to its receptors in the intestine and inhibit the growth of E. coli. Weaned piglets have an elevated pH in the gastrointestinal tract due to insufficient gastric acid secretion, which provides a suitable environment for the large-scale reproduction of E. coli, which is the main pathogen causing diarrhea. Mathew et al. pointed out that within 2 days after weaning, the lactic acid bacteria in the ileum decreased to almost zero, the pH value in the ileum increased, Escherichia coli multiplied, piglets developed diarrhea, and the addition of acidifier in piglet feed significantly reduced the number of diarrhea. Studies abroad have shown that the entry of organic acids into the intestines can change the shape of the intestines. For example, the depth of the small intestine crypts of weaned piglets can be shallowed and the height of the villi is increased. 3. Promote the absorption of minerals and vitamins Some constant and trace elements are prone to form insoluble salts in an alkaline environment and are extremely difficult to absorb. The acidifying agent can also form a complex which is easily absorbed and utilized with some mineral elements while lowering the pH of the contents of the gastrointestinal tract. Many scholars have confirmed that the addition effect of high copper and acidifier has an additive effect, that is, fumaric acid, citric acid or phosphoric acid forms a bioavailable complex with copper, which promotes the absorption and retention of copper and reduces the copper. Oxidation catalytic activity. Some organic acids such as fumaric acid have antioxidant effects, and citric acid is a synergist for antioxidants. The addition of fumaric acid to the premix was preserved for 6 months, and the stability of VA and VC was improved compared to the absence of fumaric acid. At the same time, the acidic environment of the small intestine is beneficial to the absorption of VA and VD. 4. Directly participate in energy metabolism in the body, as a source of energy Some organic acids are important intermediates in the energy conversion process and can be directly involved in metabolism. For example, the reaction of tricarboxylic acid begins with the condensation of acetyl CoA with oxaloacetate into citric acid; fumaric acid is also an intermediate of the Krebs cycle; lactic acid is also involved in metabolism in the body, is one of the end products of glycolysis, and through sugar Exogenous energy is released, so organic acids can be used as a source of energy. 5. Improve nutrient digestibility Kirchgessner reported that the addition of fumaric acid to piglet feed increased the digestibility of dry matter, energy and protein by 1.7%, 2.2% and 2.5%, and protein deposition by 4.1%. In Eckel et al., formic acid significantly increased the digestibility of dietary nitrogen. However, there are also opposite studies. Fclkowski and Hou Yongqing reported that the addition of organic acids to feeds does not improve the digestibility of dry matter and nitrogen. Giesting and other studies have shown that supplementation of fumarate in feed does not increase the apparent digestibility of nitrogen at the end of the ileum of weaned piglets. It can be seen that whether the addition of acidifier can improve the digestibility of nutrients remains to be further studied and demonstrated. Temperature Sensor&Pressure Regulator Auto Coolant Temperature Sensor,Auto Fuel Pressure Regulator Tall Automobile Parts Co., Ltd. , http://www.skye-ignition.com