Extrusion processing can passivate the anti-nutritional factors of the feed, and denature the protein and gelatinize the starch, which is beneficial to the digestion and absorption of livestock and poultry, but it also has a negative impact. 1. Negative impact of chemical processing on feed nutrients 1.1 Vitamin Loss Temperature, stress, friction and moisture will cause loss of vitamins. Coelho reported that in extruded feed, vitamin A, vitamin D3, and folic acid lost 11%, and the loss rate of ammonium sulphate monophosphate and hydrochloric acid ammonium was 11% and 17%, and the loss rate of vitamin K and vitamin C was 50%. %, the loss rate is halved in the pellets. Van der poel reported that pig feed was stored at 120 ° C for 1 month after puffing. The most lost vitamins were: vitamin K 380%, vitamin C 75%, vitamin D 25%, vitamin A and E 20%. 1.2 Loss of enzyme preparation Since the enzyme is a protein, the feed processing process has an important influence on the activity of the enzyme preparation. The optimum temperature of the general enzyme is between 35-40 ° C and the maximum is no more than 50 ° C. However, the temperature during the expansion granulation process can reach above 120-150 ° C, accompanied by high humidity and high pressure. Under such conditions, the activity of most enzyme preparations will be lost. Israelsen reported that the activity of phytic acidase at 110 °C was zero; Van der poel reported that the activity of β-glucose and fiber at 110 °C could not be measured; Gadient reported that amylase was significantly active at 80 °C. decline. 1.3 Loss of microbial preparations Microbial preparations currently have more Lactobacillus, Streptococcus, Bacillus and Yeast. These microorganisms are particularly sensitive to high temperatures. When the granulation temperature exceeds 85 °C, the activity is completely lost. Since the above three types of substances have different degrees of loss in the process of puffing or granulation, more and more scholars abroad have carried out research on the process of puffing and granulation in recent years. 2. Different post-addition methods 2.1 Direct addition of suspensions or colloids Kvanta (1987) reported that substances containing small amounts of biological activity (including vitamins, hormones, enzymes, bacteria, etc., or one of them) can be incorporated into processed food or feed. The biologically active substance is first mixed with an inert carrier to form a slurry which is insoluble and then forms a homogeneous suspension which is then converted by a device into a form which acts on the pellets. Forming a uniform film covering the surface of the pellets. Lavery (1996) also reported mixing with a viscous gel and then mixing with the feed granules. The colloid-coated particles are substantially uniform and have little contamination to the mixer, and are added in an amount of about 2-40 kg per ton of feed. These two methods of addition are more suitable for the production of small batches of feed or farm processing. 2.2 Spray Addition Liquid Novo Nordisk (1993) developed a liquid spray system that meets the requirements for the addition of liquid enzyme preparations after feed granulation. This is mainly composed of a high-precision dosing pump that sprays a precise amount of liquid enzyme preparation through a pneumatic nozzle, and the company produces a series of liquid enzyme preparations. Danisco (1996) has also developed an enzyme spray system that sprays liquid enzyme preparations onto the surface of pelleted pellets. This spray system ensures the accuracy and safety of the addition of liquid enzyme preparations and is produced by the company. A range of liquid enzyme preparations. Chevita (1998) invented a new spray application system that can simultaneously spray up to four liquid or colloidal additives on processed feed at a dose of 0.1-5 kg ​​per ton of feed. Sprout-Matador (1998) also showed a micro-liquid system that they used to add liquid ingredients to the granules, adding trace elements such as basal acids, vitamins, aromas, enzymes, antibiotics and oils. Most of these spray equipment use a pressure nozzle that allows the liquid or gel to be atomized and ejected. In general, the atomized liquid particles are small, and the surface of the feed particles is more uniformly dispersed than the direct addition of liquid or colloid. However, if the nozzle is pressurized, if the direction of the spray is wrong, the liquid will be blown to other places. After the feed dust is applied, it will stick to all the equipment in the factory, which will affect the safety and hygiene of the production. This requires good equipment. The airtightness. 3. After adding points to choose The heat-sensitive substances such as enzymes are not cooled, and the heat-sensitive substances are also lost. Therefore, the added points after the addition are generally selected after the particles are cooled, and the following three places are available: 3.1 Fuel injection equipment Some feed mills are equipped with grease traps, and there is no need to modify the process flow when installing the spray system. 3.2 Screw conveyor adopts the method of installing spray on the screw conveyor, which can save equipment cost investment. The disadvantage is that the mixing uniformity is poor, and the coefficient of variation is generally greater than 20%. 3.3 Specially designed conveyors These machines are typically placed behind a pellet cooler, such as the ChemGen rotary jet in Taiwan, which is a barrel-shaped device with a hollow rotating shaft in the center, from the top through the top cover until Close to the bottom plate, there is an arched liquid diverting disc underneath, which can rotate at high speed. There is a slightly larger feed turntable on the upper 30-60cm, which is connected to the hollow shaft. The rotation speed is slow. During operation, the granular feed falls from the top onto the feed turntable, and is evenly swept to the surrounding drum wall, and then swept downward through the liquid shunt. The outer edge of the turntable falls to the bottom plate. At the same time, the liquid is sprayed on the liquid distribution plate through the hollow shaft, and is centrifugally spread by the high-speed rotation, and evenly spreads the feed 'curtain' falling along the outer periphery. 4. Problems with the equipment after installation are not costly and the process is not complicated. Disadvantages are: 1) may increase the powdering rate of the pellets; 2) the various active substances only adhere to the surface of the feed pellets, which are easily peeled off during the transportation of the feed, resulting in loss of feed actives; 3) activity Substance adhesion on the surface is more susceptible to light and oxidation, resulting in greater loss during storage. Led Linear Light,Led Linear Strip,Led Linear Pendant Light,Recessed Linear Light JIANGMEN MICHEN LIGHTING CO.,LTD , https://www.jmmission.com