This year's shrimp disease early onset, white shrimp in South America must be vigilant

The haze of shrimp disease last year has not yet been completely uncovered. In the first few months of this year, the shadows of diseases appeared again in many parts of Guangdong, Guangxi, and Hainan. Since last year, shrimp prices have been embarrassing, but the majority of farmers have to face the plight of "shrimp is more difficult to support."

How to prevent and control diseases at different stages of shrimp farming? How to solve the problem that "the cause of shrimp disease has no solution"? What are good cases and breeding patterns? Southern China Rural Newspaper launched the column entitled “Efficient farming of shrimp,” and combined with the characteristics of each culture area, analyzed the technologies and experiences of shrimp disease prevention and treatment, and improved the benefits. The successful introduction of aquaculture models was regularly introduced to design ideal breeding programs for a large number of farmers.

"Only after the disease was released within 20 days, the shrimp pond was invisible and there were already several ponds around." On April 22, farmers in Zhanjiang told the reporters in frustration that the shrimps were after Qingming. Put, but soon after the release of seedlings found that there are shrimp in the water, swimming around the pond, individual liver and pancreas reddening, atrophy, muscle white turbidity, there is a phenomenon of stealing.

Zhuhai Hengxing Feed Industry Co., Ltd., a salesman in Xinhui Plaza, told reporters that most of the shrimp ponds that have recently been infected in Daxie are 20-40 days after the seedlings (more than 20 days). No. When the material is transferred to the crushing material, the diseased shrimp has symptoms of intestinal irritation in addition to the above symptoms. The individual shrimp and head sternum are swollen. "Preliminary judgment is likely to be Vibrio." A Qiang said that from the middle of March to now, local shrimp diseases have occurred one after another. Compared with the same period of last year, shrimp disease was more serious this year. Shrimp swimming pools are more common, and the effect of treatment alone is not. obvious.

It is understood that in Guangdong, Guangxi, Hainan and other places, shrimp ponds with earlier seedlings have been recently affected, and the amount of ponds is also in the minority. According to preliminary investigation and statistics, whether it is a generation of seedlings, second-generation seedlings, or ordinary seedlings, there are cases of onset of disease, about 20 days after the emergence of the disease as a high-risk stage, and some less than 10 days on the incidence, more Fangmiao only 2- The onset of disease in 3 days was much earlier than last year; the overall incidence rate was very high. In some places, the rate of shrimp dumplings at this stage was nearly 40%, and most of Hainan's seedlings in the period of February-March were already drained.

"I think this year's shrimp disease will be as serious as last year, and it needs to focus on the prevention of Vibrio," said Chen Junrong, general manager of Huizhou Aileen Biotechnology Co., Ltd., due to the prevalence of high-resistance seedlings, and enhanced resistance to Vibrio. The Vibrio problem was even more acute. In the past year and this year's situation, Vibrio exceeded the standard found in shrimp ponds. As long as Vibrio was exceeded, 15-20 days after seedling, the shrimp would die.

"The drainage of ponds in 20 days is mostly related to water and Vibrio. The earlier the problem is, the greater the relationship with shrimp seedlings." Chen Junrong explained that 90% or more of the drainage ponds that were seen in Zhanjiang last year were not caused by viruses. Caused by, and generally speaking, the early stage of shrimp pond farming is no problem, it is likely that shrimp and vibrio problems.

Junrong Chen suggested that every 7 days after seedling, a disease monitoring should be done to monitor the number of viruses and bacteria in the water, and the number of Vibrio and total bacteria should be monitored. The safety concentration of Vibrio should not exceed 4000-6000/ml, and the total bacterial safety value should be Above 100,000/ml. In addition, the other physical and chemical indicators also require within the safety value range, especially the ammonia nitrogen and nitrite indicators, require monitoring once every three days, ammonia nitrogen kept within 30 days 0.1mg/L, after 30 days 0.2-4mg/L The safe value of nitrite is 0.05-0.1mg/L. "If the water has high ammonia and nitrite, it means that there must be an abnormal situation, and the alert vibrio may be too high." Chen Junrong said that when dealing with ammonia nitrogen, nitrite problems, we must also consider the relationship between dissolved oxygen and Vibrio If you find that the ammonia nitrogen and nitrite are too high, you should immediately conduct Vibrio culture experiments to prevent and control Vibrio.

In the past two years, when the industry lamented that shrimp is increasingly difficult to raise, the success rate of shrimp culture in Huidong Haike Aquaculture Farm can be called a local miracle. The success rate of each shrimp production is over 80%, and the average annual yield of winter shed shrimp is 4,000. Jin, Baishui average yield of 3,000 pounds per mu. Last year, there was a one-time seedling density of 18-19 thousand tails/mu in winter and raised to more than 20 pieces/kg, with a yield of 6,000 kilograms per mu. The technician Luo Yuanhong told reporters that this has a lot to do with the long-term adherence to routine testing of algae, vibrio, and viruses. Once it is found that the algal phase is not good and the water quality index is exceeded, it will be dealt with immediately, and the vibrio medium is also used regularly. The amount of Vibrio was detected and suppressed when the epidemic appeared.