Control of microsporidiosis in cultured prawns
The main results are as follows: (1) three pathogens have been found in China: Ameson on Penaeus chinensis and Penaeus chinensis, Agmasoma on Penaeus chinensis and Pleistophora on Penaeus chinensis. The spores are oval or pear-shaped. The spores are 2-10 microns long and 1.5-4.2 microns wide. The internal structure can only be seen under electron microscope. The route of transmission of the disease is not very clear.
(2) the symptoms were different with different kinds of pathogen infection. After parasitic microworms on the muscle of Penaeus chinensis and Penaeus chinensis, the muscle of diseased shrimp becomes white, opaque and inelastic, so some people call it milky white shrimp or cotton shrimp; after the ovaries of Penaeus chinensis are infected with octosporidium, the back armour is often orange. Microsporidiosis is a chronic disease that usually weakens shrimp gradually and eventually dies.
(3) the preliminary diagnosis can be made according to the symptoms and lesions. However, viral diseases, vibrio disease and muscle necrosis can also make shrimp muscle whitening. Therefore, it is necessary to take albino tissue to make smears or water immersion slices, and spore mother cells can be observed under a high-power microscope, which can be diagnosed.
(4) the prevalence of microsporidiosis is a common and harmful disease in Guangdong and Guangxi. it is a chronic disease. the infection rate can reach 90% in the whole disease prevention cycle, and the cumulative mortality rate can reach more than 50%. Among the prawns with disease prevention and control in Qingdao, Shandong Province, the young shrimp with a body length of 1.5 cm to 3.0 cm had an acute infection, which killed hundreds of mu of young shrimp within two weeks.
(5) at present, there is no effective method for prevention and control. 5% of fish and shrimp Zhuangyuan can be mixed with feed per kilogram and fed continuously for 3 days.
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Common abnormal phenomena and treatment methods of cultured Penaeus vannamei
Abnormal phenomenon 1: before releasing seedlings, the pond could not be fertilized after many times of application of fertilizer and water, or the water color was very poor. The cause of ⑴: due to the serious excess of toxic substances such as heavy metal ions, or the proliferation of harmful bacteria and zooplankton in the pond, or the breeding of filamentous algae and green mud moss in the pond.
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Techniques of culturing sea cucumbers in ponds
With the vigorous development of sea cucumber aquaculture in China, many successful examples have been achieved in sea cucumber culture in northern ponds. In order to improve the technical level and economic benefits of sea cucumber culture, the high yield technology of sea cucumber pond culture is recommended for your reference. As soon as the ginseng pond is built
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