No matter how high the price of feed materials, soybean is always one of the most economical protein sources in pig feed. Therefore, soybean is widely planted.

However, as with most other feed ingredients, soybean is also defective. The main problem is that it contains a large number of anti nutritional factors. This will reduce the digestibility and ultimately affect the growth and productivity of the animals as well as the benefits of the breeders. The use of soybean fed to adult pigs, and sometimes also affect the digestibility, unless the full heat treatment, otherwise, it is difficult to remove these anti nutritional factors in soybean. However, excessive cooking can lead to beneficial protein denaturation, which is contrary to the primary purpose of cooking. Therefore, we need to optimize the processing conditions, to establish a balanced relationship between the maintenance of protein quality and the reduction of anti nutritional factors.

These anti nutritional factors mainly affected piglets, especially in weanling piglets. The original beneficial soy protein can cause the piglet allergic reactions, activation of piglet intestinal immune system, resulting in organism by the invasion of pathogenic microorganisms of illusion, leading to the occurrence of the phenomenon of asit (allergen specific immunotherapy). The negative reaction can cause inflammation and diarrhea and inflammation is usually damage the lining of the intestines, pathogenic bacteria adhesion and exotoxin absorption provide convenience. Although the whole process will not exceed one week before the immune system stops responding, the damage is long and multifaceted. In general, there will be associated with infection of pathogenic bacteria.

In order to solve this problem, the industry put forward two views, one is to promote the introduction of soy protein immediately after weaning (assuming that the piglets have not or little contact with the teaching material before weaning). While people suggest that weaning should be gradual introducing soybean protein, but this view for soybean meal in weaning after the first dietary use of about 10%, in the second diet to quickly increased to 15%, the rest followed by analogy. This approach requires piglets with a higher level of feed intake to ensure that the impact is minimized. The negative effect of soy protein on the negative effects of soybean protein was increased when the feed intake was lower than the maintenance requirement.

The advantage of this method is that: 1) the formula cost is low; 2) piglets adapt to the soybean protein fast; 3) the number of food changes is small. In contrast, disadvantage is that the diarrhea rate is high, especially is not ideal in the health status of the farm.

To solve the same problem, another more moderate approach, is in after weaning the first diet does not use any soybean products, in the diet in the form of refined products using a small amount of soy protein (as in almost does not contain anti nutritional factors in soybean protein isolate). The key point of this method is similar to that of the first method. However, the main difference between the two is that the second methods of weaning stress and the problem of soy protein separate. Often, these two problems are considered as a whole; but no matter how close they are, they are obviously different. Second methods are suitable for those who have health problems, but the food price is expensive, it is difficult to bear. Therefore, from a market perspective, this approach is not ideal.

Of course, between these two kinds of more extreme methods, the industry has also tried to use a number of other methods, and in the application process has made a different degree of success. Two methods of compromise has many advantages, thus preparing the diets for those health status is unknown for swine. Generally speaking, in the author's personal experience, the following six kinds of soybean application method is the best: