Great loss of benefit from damage to fish liver how to prevent and treat fish hepatobiliary syndrome

In recent years, with the improvement of the intensive degree of aquaculture, the incidence of fish hepatobiliary syndrome has also increased a lot. All kinds of cultured fish can be infected with hepatobiliary syndrome, especially carp and grass carp, and the incidence of adult fish is high.

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Cause: ⑴ pathogenic microorganisms, such as Aeromonas hydrophila, Edwardsiella, rhabdovirus, reovirus and other infections, will directly or indirectly cause fish hepatitis.

Nutritional factors of ⑵. Too high nutritional level of feed can easily lead to cod liver disease. High-protein feed can easily lead to liver fat accumulation, damage liver function, interfere with normal physiological metabolism of fish; too many carbohydrates in feed lead to sugar metabolism disorder of fish, cause visceral fat accumulation, hinder normal function, and cause fatty liver; excessive feeding of fatty feed can also cause liver disease. In addition, feed nutrition index is not consistent with fish species, such as feeding blunt snout bream or grass carp with carp feed, and feeding adult fish with fry and fingerling feed will also lead to fish liver disease. Excessive feeding, uninterrupted intensive feeding every day, leading to excessive growth of fish, obesity and fatty liver. The aldehydes contained in oxidized rancidity fat in fish feed are toxic, damage fish liver and affect liver function.

⑶ drug factors. Such as heavy metal poisoning, pesticide, ammonia nitrogen, nitrite, hydrogen sulfide poisoning will cause fish liver degeneration, necrosis. Long-term addition of drugs that damage the liver of fish 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 damage the liver of fish. The use of high-dose insecticides is also easy to damage the liver of fish.

Prevention and treatment methods: ⑴ is fed scientifically with high-quality feed. Follow the principle of scientific fish culture, use nutritious and comprehensive fish feed, do not overfeed, prevent protein deterioration and fat oxidation, prevent feed from damp and mildew deterioration.

⑵ was used correctly. Do not add low-dose, long-term drugs that can damage the liver of fish, such as oxytetracycline, sulfonamides, tetracyclines, etc., and do not use fish drugs with large side effects and high residues, such as trichlorfon, copper sulfate, etc. what is more, fish drugs banned by the state or pesticides should not be used instead of fish drugs. When treating cod liver disease, we should try to find out the pathogen and cure both symptoms and root causes.

⑶ reasonable close culture, good management of water quality control. The stocking density of fish should be reasonable, which should be determined according to the water depth of fish pond, sediment condition, water source, feed supply and culture level. If the culture density exceeds the capacity of the fish, it will increase the stress of the fish and damage 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 disease.