Analysis of the Causes of Chicken Immunosuppression and Effective Countermeasures

With the deepening of research on @#@230@#@ health care, people have gradually come to clearly recognize the harmfulness and severity of the immunosuppression problem in chicken flocks. As far as chicken flocks are concerned, what exactly causes immunosuppression?

1 Causes of immunosuppression

1.1 Chickens contracting diseases that can cause immunosuppression

In disease prevention and control work, the common infectious bursal disease, avian influenza, avian leukosis, Marek's disease of chickens, and so on are all diseases that severely attack the body's immune system and cause immunosuppression. For example, the main pathological feature of infectious bursal disease is usually attacking the bursa of Fabricius, causing inflammation or swelling and bleeding of the bursa of Fabricius; and the body's B cells, as one of the most important immunogenic cells, are generated by the bursa of Fabricius, which is also an extremely important immune target organ in the humoral immune system. Tests have shown that removing a chicken's bursa of Fabricius causes almost all of the body's immune organs to be unable to express, the whole-body immune system to be suppressed, severely affected organs to face failure, and ultimately death. Avian influenza attacks the body even more severely; it not only damages the bursa of Fabricius but also destroys systemic immune organs such as the thymus, pancreas, ceca, and tonsils, and even the hematopoietic function of the bone marrow is damaged. The thymic hemorrhage caused by avian influenza directly causes devastating damage to the body's production of T cells, and the bursa of Fabricius suffers the same fate; this is one of the most fundamental reasons for sudden death and large-scale death of chickens.

1.2 Toxic side effects of drugs causing immunosuppression

There are many drugs that can cause immunosuppression in actual production, such as furazolidone, sulfonamide drugs, chloramphenicol, thiamphenicol, penicillin, chlortetracycline, and so on. These drugs often cause anemia and immunosuppression because they themselves have the property of inhibiting bone marrow hematopoietic function and inhibiting bone marrow synthesis of immunoglobulins. Even drugs such as amantadine, ribavirin, and moroxydine are often reported in clinical practice as having the possibility of causing teratogenicity and anemia. At present, many small veterinary drug companies, for petty gains and in pursuit of maximizing profits, disregard repeated state prohibitions and still apply these drug components that can cause immunosuppression to drug formulas.

1.3 Excessive and unscientific use of vaccines causing immunosuppression

In immunology, it is a fact that the amount of vaccine used is positively correlated with the immune effect, but just like the spring principle, this is only correct within a certain limit and a certain period; once the range of use is exceeded, it has the opposite effect. As far as live vaccines themselves are concerned, although they are attenuated, they are after all toxic products; severely excessive use will make their effective toxicity reach the toxicity of wild strains. For example, for the Newcastle disease Lasota strain, generally when used within the range of 1 dose to 6 doses, the dosage is positively correlated with the immune effect, but adding more on this basis is not only meaningless and unnecessary, but once the dosage reaches 10 to 12 times, there will be a certain toxic manifestation and a severe immunosuppressive reaction; if used in severe excess, it will cause death in the chicken flock due to infection caused by human factors.

1.4 A large number of stress responses causing immunosuppression

In daily work, measures such as vaccination, excessive cold, excessive heat, catching, moving groups, beak trimming, and feed changes will cause metabolic disorders in the body due to fear or unease, causing vaccination to fail to effectively stimulate immune target organs to produce an immune response, leading to immune failure.

1.5 Improper medication or incorrect vaccination causing immunosuppression or immune failure

Drug poisoning will cause inflammatory or hemorrhagic reactions in immune organs, thereby causing immune suppression or low-efficiency expression; moreover, the vaccination method for each vaccine is not exactly the same, and different vaccination methods will produce different immune effects. Improper vaccination methods can also cause immunosuppression.

1.6 Moldy feed causing aflatoxin poisoning and thus immunosuppression

In recent years, the problem of feed mildew is a problem that every farm (household) must face and should treat seriously. Aflatoxin often infects chickens by contaminating feed. Once chickens suffer from aflatoxicosis, severe cases are fatal, while mild cases cause immunosuppression and can easily lead to long-term illness. The reason is very simple: aflatoxin often attacks the chicken's respiratory system within the body.

1.7 Lack of trace elements in feed causing immunosuppression

The balance of the nutritional levels of various mineral elements in the diet is an important part of maintaining the body's normal physiological metabolism and strengthening physical constitution. As far as its effects are concerned, maintaining a normal immune response is an important part. Scientific tests have shown that the element zinc is one of the important elements for the bursa of Fabricius to maintain normal development and functional action; if deficient or insufficient, it will cause atrophy of the bursa of Fabricius, with severe cases being only 1/2 to 3/5 of the normal bursal body, thereby easily causing the occurrence of immunosuppressive diseases. The element selenium is an important preventive element for the body's white muscle disease and is also one of the important elements for bone marrow hematopoiesis and antibody synthesis. At present, in people's daily life, selenium has already been added as one of the indispensable nutritional elements to table salt or food to meet the body's normal needs.

1.8 Environmental pollution causing immunosuppression

Farm pollution is one of the headaches for many farm (household) owners in China. Large amounts of livestock and poultry excrement are unreasonably piled around the farm area or on roads. If it cannot be effectively and promptly treated, it will produce large amounts of toxic and foul-smelling gases, such as hydrogen sulfide, cadaverine, ammonia, and so on. These harmful gases not only cause symptoms of poisoning and discomfort in humans such as dizziness, vomiting, and shortness of breath, but also cause adverse reactions in chicken flocks, thereby triggering immunosuppression.

2 Countermeasures

2.1 Select high-quality and efficient vaccines

Strictly implement vaccination procedures and formulate scientific prevention and immunization programs for laying hens. Although the vaccines currently circulating on the market have all passed CMP system certification, their product quality reliability and efficiency are uneven, and some vaccine products, due to incomplete purification work, still contain some pathogens that can cause horizontal transmission of infectious diseases. Therefore, selecting high-quality, efficient, and safe vaccines is a very important link.

2.2 Select reliable drugs

In the process of preventing and treating diseases, select drugs from manufacturers with reliable quality and good reputation as much as possible, so as to avoid unnecessary trouble caused by drug toxic side effects (including the problem of drug residues in poultry products and the problem of immunosuppression in the body).

2.3 Select health products that relieve and avoid immunosuppression

Such as interleukin, interferon, and so on. As far as interleukin is concerned, this product can not only activate and enhance the efficacy of the cellular immune system, but also eliminate inhibitory factors of the humoral immune system and relieve humoral immune suppression, thereby placing both the cellular immune system and the humoral immune system in a state of efficient expression and keeping the body in a strongly healthy state.

2.4 Improve the environment

Eliminate pollution factors and stress factors that cause immunosuppression and enhance the body's physical constitution.

2.5 Strictly control feed nutrition

On the one hand, toxic and contaminated feed must absolutely not be used. On the other hand, high-quality feed is required to ensure that the content of nutritional components is balanced and stable and can be efficiently digested and absorbed.