Comprehensive prevention and treatment of fish hepatobiliary syndrome

In recent years, with the increasing intensity of aquaculture, the incidence of fish hepatobiliary syndrome is getting higher and higher. Hepatobiliary syndrome can occur in all kinds of farmed fish, especially carp and grass carp, and the incidence of adult fish is generally high.

There are many causes of hepatobiliary syndrome in fish, which can be summed up in the following aspects. ⑴ pathogenic microorganism infection. Such as Aeromonas hydrophila, Edwardsiella and pathogenic microorganisms such as rhabdovirus and reovirus will directly or indirectly cause hepatitis in fish. Pathogenic microorganisms multiply in large numbers in fish liver, produce toxins, cause metabolic disorders of hepatocytes, and lead to degeneration and necrosis of hepatocytes. Nutritional factors of ⑵. Too high nutritional level of feed can easily lead to fish liver disease. High-protein feed is easy to induce liver fat accumulation, destroy liver function, and interfere with the normal physiological metabolism of fish; excessive carbohydrate content in feed will cause fish sugar metabolism disorder, cause visceral fat accumulation, hinder normal function, and cause fatty liver; feeding feed containing too much fat can directly cause liver disease. In addition, the nutritional index of feed is not suitable for breeding objects, such as feeding blunt snout bream or grass carp with carp feed and adult fish with fry and fingerling feed will cause liver disease. Excessive feeding and continuous intensive feeding many times a day will lead to excessive growth of fish, obesity and fatty liver. The aldehydes produced by oxidized rancidity fat in fish feed have great toxicity, cause great damage to fish liver and affect the normal function of liver. ⑶ drug factors. Such as heavy metal poisoning, pesticide, ammonia nitrogen, nitrite, hydrogen sulfide poisoning, will cause fish liver tissue degeneration, necrosis. Long-term addition of drugs harmful to fish liver and improper use of drugs are the main causes of drug-induced hepatitis. Long-term addition of high-dose olaquindox, flavomycin and other growth-promoting drugs will cause liver damage in fish. The use of high-dose insecticidal drugs is also easy to accumulate in the fish body, directly damage the fish liver.

As there are many causes of fish hepatobiliary syndrome, comprehensive measures should be taken to prevent and cure it. ⑴ chooses high quality feed and feeds it scientifically. In strict accordance with the requirements of science, choose feed with rich and comprehensive nutrition, avoid excessive feeding, prevent protein deterioration and fat oxidation, and prevent feed from damp and mildew. ⑵ was used correctly. Do not add low-dose, long-term drugs that are harmful to the liver of fish, such as oxytetracycline, sulfonamides, tetracyclines, etc.; do not use fish drugs with large side effects and high residues, such as trichlorfon, copper sulfate, etc., what's more, fish drugs prohibited by the state or pesticides instead of fish drugs should not be used in the water. In the treatment of cod liver disease, we should try to find out the pathogen and cure both symptoms and root causes. ⑶ reasonable close culture, do a good job of water quality control. In order to control the stocking density of fish reasonably, it must be determined according to the water depth of fish pond, the condition of sediment, the supply of water source and feed, and the level of culture. The culture density exceeds the bearing capacity of the fish, which will increase the stress response of the fish and cause damage to the liver. When the concentration of ammonia nitrogen in water is too high, the metabolites of ammonia in fish are difficult to be excreted normally and accumulate in the blood, which is also easy to cause fish liver and gallbladder diseases.