Shrimp farming has formed a large industry in China, but every year due to diseases caused by ponds, deaths and other huge losses. Disease control is the key to high and stable shrimp farming. In the process of breeding, when diseases occur, farmers often think that it is an infectious disease, blindly disinfecting with water bodies and feeding antibiotics, but the effect is not ideal.
In addition to infection with bacteria, viruses and parasites, shrimp diseases also have causes of poisoning, environmental stress and hypoxia caused by algae, ammonia nitrogen, nitrite and hydrogen sulfide. In the process of breeding shrimp, due to poisoning, stress and hypoxia causes caused by empty stomach, red body, sneak death, such as the use of water disinfection and feeding treatment, and ignore the improvement of the breeding environment and the adjustment of water quality indicators, not only can not alleviate the symptoms to recovery, but also may lead to worsening of the disease, increased death, and eventually failed to breed.
According to the basic theory of shrimp farming, combined with the author's many years of experience in breeding and disease prevention and control, the diagnosis and treatment ideas of common diseases caused by environmental degradation in shrimp farming are summarized for the reference and reference of the majority of farmers.
1. Stress red body, red legs
1. Symptoms: hard carapace, dull body color, redness, obvious redness of swimming feet and tail fans, quickly restore the original body color after fishing away from the water body, redness of liver and pancreatic envelope, rarely lying on the edge during the day but there is a phenomenon of jumping pond.
2, identification: water quality deterioration, ammonia nitrogen, nitrite, hydrogen sulfide is high, the bottom of the pool is black and smelly. Shrimp have an adaptive response (stress) to exceeding water quality indicators and deteriorating pool floors, resulting in reddening of appendages, loss of appetite, and severe redness. Catch a few shrimp with obvious red bodies and still eat, and use buckets of surface water from the original pond for 1-2 hours. If the symptoms disappear, it means that the pool bottom has seriously deteriorated, and it is only necessary to improve the bottom environment to recover.
3, treatment: with multi-dimensional 200 g / mu rice + surfactant 300 g / mu rice sprinkling, to relieve stress reaction, improve shrimp vitality and appetite; at night with 30% potassium persulfate tablets 400 g / mu m + surfactant 150 g / mu rice dry sprinkling, continuous use for 2-3 days, change the bottom deodorization, improve the dissolved oxygen at the bottom of the pool; finally use EM bacteria or photosynthetic bacteria 2-3 kg / mu rice sprinkling, improve and stabilize water quality, absorb ammonia nitrogen, nitrite and other harmful substances, promote the balance of bacteria and algae, improve the self-purification ability of water bodies.
Second, environmental black gills
1. Symptoms and identification: the gills are gray-black, and the gills are cleaned with clean water to return to normal.
2. Cause: insufficient dissolved oxygen at the bottom of water stratification or harmful substances such as ammonia nitrogen and nitrite stimulate the gills to secrete mucus, and the dead algae and other dirt in the water are adhered to the gills when breathing. Cut the black gill wire, clamp it with forceps, and shake it in the clear water, and the gill wire black color is significantly lighter. Microscopic examination revealed no swelling, ulceration, discoloration of the gills, only adhesion to black dirt.
3, treatment: in the morning with hydrated lime (4-8 kg / mu) sprinkled, flocculation of pollutants suspended at the bottom of the pool, improve the turbidity phenomenon of the bottom of the pool; in the afternoon, use calcium peroxide 1 kg / mu rice + surfactant 250 g / mu rice mixed dry sprinkling, improve water permeability and dissolved oxygen; in the evening 10% potassium perferrate 200 g / mu m + 30% potassium persulfate 200 g / mu m, severe use for 2 days, oxidation of reducing pollutants at the bottom of the tank, promote the degradation of pollutants.
■ Toxic substances exceeding the standard (above)
3. Stress muscles are cloudy and spastic
1. Symptoms: shrimp muscles are white and turbid, vitality is reduced, muscle spasms and bend to the abdomen in severe cases, body stiffness, loss of swimming ability, lying on the side of the pool bottom.
2. Identification: In line with the above symptoms, the total alkalinity and total hardness of the water body are low. The lack of dissolved trace elements in the water body seriously affects the growth and molting of shrimp, and in severe cases, it leads to molting and stealing death.
3, treatment: calcium magnesium and trace elements 1.5 kg / mu rice + multi-dimensional 200 g / mu rice sprinkling, supplement the trace elements of the water body; at night with calcium peroxide 2-3 kg / mu rice sprinkled or 30% potassium persulfate tablets 200 g / mu rice dry sprinkling, oxidize the bottom of the pool to reduce the substance, improve the dissolved oxygen at the bottom of the pool; in severe cases, use for 2 days.
■ cramps ・ white turbidity
4. Death (symptoms of hypoxia of nitrite)
1. Symptoms: Most of the dead shrimp do not have any obvious symptoms, the body color is dark red or reddish, and the dead shrimp are white or blue.
2. Identification: in line with the above symptoms, nitrite, ammonia nitrogen exceed the standard, the pH value is low, and the dissolved oxygen of the bottom layer is low.
3, treatment: during the day with surfactant 500 g / mu rice + calcium peroxide 1.5-2.0 kg / mu rice + calcium and magnesium and trace elements 1 kg / mu rice, improve water permeability and dissolved oxygen, supplement the trace amount of water, alleviate the secret death; 4 hours later with sulfur bacterial particles 200 g / mu rice + denitrification bacterial particles 200 g / mu rice dry sprinkling, severe use for 2-3 days, degrade the pond exceeding the standard of ammonia nitrogen, nitrite and hydrogen sulfide and other toxic substances, improve the dissolved oxygen of the water body.
■ Nitrite exceeding the standard, enteritis
5. Stress enteritis
1. Symptoms: empty stomach and jejunum, intestinal segmentation or fecal thinness, water disinfection and traditional Chinese medicine or antibiotic mixing have no effect.
2, identification: relative to bacterial enteritis, stress enteritis develops rapidly, the number is large, often more than half of the whole pond disease shrimp in one or two days, and the incidence of shrimp is relatively many. Before the onset of the disease, there are often strong stresses such as wind and rain, high temperature and low pressure, or inverted algae.
3, treatment: with multi-dimensional 200 g / mu rice + surfactant 300 g / mu rice sprinkling, relieve stress, improve shrimp vitality; 4 hours with sodium humic acid 2-3 kg / mu rice + lactic acid bacteria 1 kg / mu rice spilled, detoxification and anti-stress, improve appetite and promote the recovery of the intestine.
■ Enteritis
6. Toxic liver atrophy
1. Symptoms: liver and pancreas are obviously atrophied, the surface is blue or green; the shell of shrimp is soft, most of them appear yellow and green, and the jejunal and empty stomach phenomenon occurs; in severe cases, shrimp have a large number of deaths.
2. Identification: In line with the above symptoms, there are more dead algae in the water body, and there are more naked algae, dinoflagellates, and cyanobacteria. The table has blue-green feces, microscopic examination of the intestine, and the intestines have detritus of harmful algae such as dinoflagellates and naked algae.
3. Treatment: in the morning, use poplar flower extract 500 g + sodium thiosulfate 500 g/ mu rice mixed sprinkling, detoxification and liver protection; afternoon humic acid sodium 2 kg + photosynthetic bacteria 2 kg / mu rice spilled, severe time for 2 days, adsorption of algal poison and water transfer. Finally, 1-2 kg/mu of rice is sprinkled with lactic acid bacteria solution to improve appetite and whole intestines and protect the liver.
Seventh, the soft shell and the molting shell do not succeed
1. Symptoms: The carapace of the diseased shrimp is thin and soft, weak, inactive, easy to steal death or be eaten by the same kind, and there are dead shrimp.
2. Identification: the shrimp body color is normal, the shell is soft, and the vitality is poor; the dead shrimp have soft shells and double shells. The total hardness of the water body is insufficient, and the shrimp molting cannot absorb enough calcium and magnesium ions from the water body, resulting in the inability to be hard shell after molting.
3, treatment: calcium and magnesium and trace elements 1.5 kg / mu rice + multi-dimensional 200 g / mu rice + coarse salt 15 kg / mu rice (fresh water) sprinkling, supplement calcium magnesium ions and vitamins, promote soft shell shrimp to absorb calcium and magnesium ions in the water body; at night with calcium peroxide 2-3 kg / mu rice sprinkling, improve water dissolved oxygen and shrimp vitality; in severe cases, use for 2 days.
The above is a shrimp farming process, common environmental substandard caused by or environmental mutations caused by diseases, the control of such diseases often do not require water disinfection and feeding antibiotics and other drugs, through water quality improvement can achieve the effect of disease prevention and control.
Through the discussion of this article, it is suggested that farmers can diagnose the causes of diseases through dialectical analysis and diagnosis when diseases occur in aquaculture animals. Diseases caused by environmental degradation can be prevented and controlled by improving the water environment. In this way, the risk of treatment can be reduced, and the use of veterinary drugs can be reduced, and the breeding commodity shrimp can be guaranteed to be free of drug residues and the breeding environment is not polluted, so as to achieve truly green and healthy breeding.