As an important energy source, fat not only has a high energy level, but also has a low heat increase. It can also provide essential fatty acids to the body and act as a solvent for fat-soluble vitamins to promote the absorption of vitamins and fat-soluble substances. However, practice has proved that the effect of using fat in the diets of young animals is not ideal. Even in the diets of adult livestock and poultry, adding a large amount of fats cannot achieve the expected results. This phenomenon is mainly due to insufficient bile acid secreted by the endogenous emulsifier, which makes it difficult to fully emulsify, hydrolyze and absorb neutral fats such as triglycerides. In particular, the lack of bile acids limits the fat degradation Absorption of long-chain fatty acids.

In recent years, a large number of studies and experiments have been conducted on emulsifiers. Tests have shown that the addition of exogenous emulsifiers can increase the emulsification rate of oils, increase the digestion and absorption rates of oils, and expand the scope and proportion of oils used. One of the important means of poultry production performance. However, the addition of emulsifiers is not only to emulsify fat and improve digestibility, but the ultimate goal is to increase the absorption rate of fatty acids after fat degradation, so that the ingested fat can be fully utilized, so it is very important to choose which type of emulsifier.

Emulsification is a process in which two immiscible liquids are dispersed in the other liquid in the form of tiny droplets to form an emulsion. Emulsion can be roughly divided into two types: oil-in-water (O/W) and water-in-oil (W/O). In addition, there is a very complex multiple emulsification (such as O/W/0 type, W/O/W type), for animal digestive tract, generally belongs to the oil-in-water type (O/W). These dispersion systems of emulsions are generally very unstable, and often need to add a third component-emulsification

The animal intestine is a water-soluble environment, and emulsification will form an oil-in-water emulsion. From the above figure, it can be seen that the closer the hydrophilic-lipophilic balance value is to 20, the better the effect of the emulsifier. Compared with other types of emulsifiers, emulsifiers with an HLB close to 20 are easier to disperse in water, and the HLB value of bile acids is 19, which is better than other phospholipids (HLB 7.5) and monoglyceride emulsifiers. Hydrophilic and lipophilic properties.

Emulsification is not equal to digestion. The digestion and absorption of fat includes three processes: emulsification, fat hydrolysis and absorption. The small fat droplets formed by emulsification need to be hydrolyzed into free fatty acids, glycerol and monoglycerides under the action of lipase, and then form chylomicrons. Enter the epithelial cells of the small intestine to be absorbed and utilized. As an endogenous emulsifier, bile acid not only has the advantage of natural emulsification, but also activates the activity of lipase and promotes the formation of chylomicrons. Studies have shown that the lipase secreted by the pancreas of young animals is only 4% of that of adult animals, while the concentration of bile acid in bile is only 10%-25% of that of adult animals, which is even lower under stress conditions. The lack of endogenous bile acids seriously affects the digestion and absorption of fats. The addition of exogenous bile acids can increase the fat utilization rate by 15%-30%, while avoiding fat waste and unreasonable fat deposition. Health problems.