凯恩格生物科技（宜昌）有限公司
Immunity is an animal body's defense against the external environment and microorganisms. It is because of the existence of various immunity that animals can survive in a complex environment. Immune organs include central immune organs and peripheral immune organs, which refer to bone marrow, thymus, bursa of fabric (poultry), and related lymphatic tissues such as lymph nodes, spleen, and mucous membranes. We often say that the intestine is the largest immune organ, and it makes sense, because intestinal microbes are the place where animals interact most frequently with the environment. Microbes are stimulating and affecting the immune system. A sterile animal has relatively weak immune system development.
We also need to fully consider how to balance the body's immune system when we are replacing antibiotics. The reason for balance is that on the one hand, immunity consumes nutrients, and too strong immunity will cause the body to enter a state of self-defense, lethargy and less food, which affects production performance. On the other hand, the immune system cannot be too weak, otherwise it cannot resist the invasion of harmful microorganisms. This needs to be considered from the intestinal flora and intestinal immunity.
1. Classification of the immune system
Immunity is divided into innate immunity and adaptive immunity. Innate immunity is non-specific, and adaptive immunity is specific. The modern definition of immunity is more complete, including the body's natural physical barrier, which is regarded as the first line of defense, phagocytosis of white blood cells as the second line of defense, and specific lymphocytes and antibodies as the third line of defense.
These three lines of defense are very important for the alternative antibiotics, and we will be involved in the preparation of the formula, the use of additives and the actual feeding and management process.
2. Innate immunity
The physical barrier of the first line of defense against intestinal mucosal immunity includes: the mucous layer of the intestinal epithelium, the intact intestinal epithelium, and the tight junctions of the intestinal epithelium. We will consider these parts in the actual diet production. For example, fiber and probiotics can maintain a complete mucus layer. Zinc oxide and probiotics can increase the expression of tight junction proteins in the intestine, especially zinc oxide. Butyric acid, plant extracts, etc. can reduce inflammation, and can also ensure complete intestinal epithelium and tight junctions. Therefore, the first line of defense is very important. Many factors considered in the diet will also play an important role in this regard.
The second line of defense is very important for us to actively control the body's immunity, especially in a relatively poor environment, where we need to resist stronger and more harmful bacteria and balance the inflammatory response. Intestinal epithelial cells are composed of many different cells, such as the most epithelial cells, goblet cells (secreting mucus), M cells (transporting bacteria into the body across the epithelial layer to initiate an immune response), macrophages (phagocytosis), and dendrites Cells (collecting microorganisms, digesting pathogens, presenting antigens to T cells), etc. Among them, there are a large number of special structures distributed on macrophages and dendritic cells, which are called receptors. These receptors are the innate immune functions developed in the evolutionary process of animals for thousands of years. There are many different receptors in the body, such as Dectin, TLR, NOD, etc. Different receptors can recognize different microorganisms and mediate different cytokine changes. Among them, yeast derivatives are the most commonly used in animals, and bacterial derivatives are also used in humans. For example, β-glucan can stimulate Dectin-1 receptors, thereby enhancing non-specific immunity in the body.
The regulation of phagocytosis needs to be balanced. To stimulate a single receptor, there will be two problems: one is the amount of use, not too much, otherwise it will easily cause immune fatigue and inflammation. Second, the problem of using time, too single use for a long time will also bring adverse reactions.
Lallemand's experiments have shown that the regulation and stimulation of multiple receptors can efficiently and balance the regulation of immune response, with strong immunity, and at the same time, it will not cause too strong or single response.
3. Acquired immunity
Acquired immunity is the most concerned about pigs and chickens, which are B, T cells and antibodies. Why is there such a high degree of awareness and attention to this? Because there are many viral diseases in the breeding of pigs and poultry, the ultimate solution to these viral diseases is vaccines, through which antibodies are produced in the body, so as to ensure the health of the production animals. Just like we are all looking forward to ASF and the new coronavirus vaccine.
Suckling piglets obtain antibodies from colostrum. The passive immunity gained gradually declines. The piglet’s own immunity continues to develop, but the total immunity is just at the lowest point before and after weaning, so various stresses are caused at this time. The impact and destruction of the situation is even greater. Colostrum and antibody levels significantly affect the health and growth of pigs. The more colostrum and antibody levels, the less diarrhea and the higher of weaning weight. As shown in the figure below, for every additional 100g of colostrum, the weaning weight will increase by 366 grams.
To increase the IgG level of suckling piglets, we need to start from two aspects: 1. The level of IgG in sow colostrum. 2. Colostrum intake of suckling piglets. To increase the level of IgG in the colostrum of sows, you can use S.boulardii®, fiber and other products that regulate intestinal health, omega-3 polyunsaturated fatty acids, and the reduction of anti-oxidative stress, or through sow immunity. Increasing the colostrum intake of suckling piglets requires management of the sow's constipation and labor process. The less constipation and the shorter the labor process, the stronger the birth vitality of the suckling piglet, and the higher the colostrum intake. When the sow’s teats are not enough, foster care should be arranged in time.
Immumne is an important and complex topic. Researchers are also constantly in-depth understanding and research. The latest knowledge about immune is updated very quickly. For us to replace antibiotics, we need to clearly understand the characteristics of intestinal mucosal immunity and pay more attention to non-specific immunity. Because the main target of antibiotics is bacteria, the non-specific first and second lines of defense are more important than viruses. Innate immunity and adaptive immunity are also interrelated. The initiation of immunity starts with non-specific immunity, such as destroying mucus and mucosal barriers, then macrophages and dendritic cells are activated, followed the antigen digested by dendritic cells is presented to lymphocytes, which initiates adaptive immunity. In 2011, the Nobel Prize in Physiology and Medicine was awarded to three scientists who study immune initiation and regulation. One of their important findings is that the lack of non-specific immunity can lead to the loss of corresponding specific immunity.
It is rather boring to express it in language. I translated a video about mucosal immunity produced by Nature into Chinese subtitles, so that everyone should have a clearer understanding of the intestinal immune system.
