The role of demonstrating liver lesions in chickens

The liver is soft and brittle and brownish red because of its rich vascular supply. It is not only the largest gland in chicken, but also the largest detoxification organ. It plays a very important role in bile production, coagulation, immunity, heat production and the regulation of water and electrolytes. At the same time, the liver is also a very important barrier mechanism, so it is vulnerable to damage caused by a variety of pathogenic factors. Different pathogenic factors cause different liver lesions, so different liver lesions have a specific role in diagnosis. The types of liver lesions and their diagnosis in specific diseases are summarized as follows.

There is local necrosis on the surface of the liver.

Focal hepatocyte necrosis, local tumor cell infiltration or foreign body deposition cause yellow-white or gray-white necrotic foci on the surface of the liver.

The liver of avian cholera is crisp and fragile, and there are many gray-white necrotic foci the size of chestnut rice under the capsule and on the section. Microscopic examination showed that there were multiple small necrotic foci in the liver and characteristic cholera bacteria could be seen in the foci.

The liver parenchyma of chicken pullorum is covered with white or gray needle-sized nodules. In addition, the liver is enlarged, brick-red, with bleeding spots.

There are chrysanthemum-shaped and reticular necrotic foci on the surface of chicken blackhead liver, and the center of ulcer is yellow or grayish green. Microscopic examination showed red round worms.

Chicken tuberculosis liver is crisp, often brownish red, with grayish-white or yellowish-white nodules of different sizes in the liver parenchyma. The fusion of multiple lesions was cauliflower-like hard nodules. Microscopic examination: the disease is characterized by tuberculosis nodules with caseous necrosis in the center of tuberculosis nodules and generally without calcification.

There are grayish-white tumor nodules on the liver surface of Marek's disease and lymphocytic leukemia. The changes of liver and eye view of the two are very similar and need to be differentiated by comprehensive diagnosis.

Chicken aflatoxin liver is pale and pale with yellow nodules of rice grains on the surface.

Uric acid deposition is caused by a large number of uric acid deposits in the body due to renal dysfunction caused by a variety of reasons. There was calcareous urate deposition on the surface of diseased chicken liver, and urate deposition lesions could also be seen in other organs and tissues. Microscopic examination showed needle-like urate crystals.

The liver capsule thickens and exudates are attached to the capsule

This phenomenon is caused by hepatic capsulitis and cellulose exudation on the surface of the liver. It is more common in colibacillosis, blackhead and ascites disease.

The main pathological changes of colibacillosis are hepatic capsule thickening, liver necrosis, pericarditis and peritonitis.

Cellulose exudation can be seen on the liver surface in the early stage of blackhead, and there are characteristic liver necrosis and cecal lesions in the later stage.

Ascites is caused by a large amount of cellulose in the exudated ascites, which precipitates on the liver.

Hepatomegaly

Many diseases are accompanied by varying degrees of hepatomegaly. The following are briefly described here:

Fatty liver syndrome often occurs in the peak period of egg production or high-yield chicken flocks. High-energy diet and lack of exercise are the main factors of the disease. During the autopsy, the liver was enlarged, fragile, fragile, steatosis of the liver, light yellowish color, and easy to rupture, and sometimes small bleeding spots and white necrotic foci could be seen.

Inclusion body hepatitis this disease is caused by adenovirus, can cause hepatomegaly fade, crisp, there are very clear bleeding spots on the surface, and the section can also be seen. Microscopic examination showed that there were inclusion bodies in the liver nucleus, severe metamorphism and vacuolation of hepatocytes, and hemorrhagic foci formed by erythrocyte aggregation in the liver parenchyma.

Other causes and many other pathogenic factors can also cause certain damage to the liver, which can cause metabolic disorders of hepatocytes, resulting in a series of pathological changes such as enlargement, degeneration and necrosis of the liver. Such as chicken pullorum, Marek's disease, chicken blackhead disease and so on, are not explained here.

Summary

The characteristic naked eye (microscopic examination) lesions of the liver can only be used as a reference for the diagnosis process, but also combined with the pathological changes of other organs, feeding and management to make a diagnosis, if necessary, with the help of serology and other methods. In addition, the modern breeding industry makes the pathogens under the pressure of immunity and drugs for a long time, the pathogens are constantly changing, the diseases of livestock and poultry are becoming more and more complex, and the characteristic pathological changes are not obvious, so it is more necessary to analyze the factors in the feeding process to make a comprehensive diagnosis.