Seedling raising techniques of Macrobrachium rosenbergii

1. Pretreatment of source water When the water temperature is low in winter, source water is injected into the pond and the pond water is disinfected with quicklime. After 1 ~ 2 months of sedimentation and disinfection, the water quality index of pond water can reach a good state in the seedling season.

2. Intensive rearing of parent shrimp During the whole seedling raising period, it is necessary to increase the feeding of animal bait, and to add a variety of vitamins, immune polysaccharides and other substances to the feed. The daily feeding amount should be 5% ~ 7% of the shrimp's weight, and the feeding amount should be adjusted at any time according to the shrimp's feeding situation, so as to increase the water exchange quantity and times and keep the water fresh, so as to promote the rapid maturity of the gonads of the parent shrimp and mate and lay eggs in the pool.

3. Comprehensive prevention and control measures should be taken for disease control, focusing on prevention and combining prevention with treatment. Nursery ponds and nursery tools should be strictly cleaned and disinfected before and after use. After each shrimp catching operation, the parent shrimp pond is thoroughly disinfected with high concentration potassium permanganate. When the seedling water enters the water, the water source can be filtered by 200 mesh gauze. Regularly carry out virus detection on larvae (especially after desalination).

4. Formulate a strict management system for conservation areas. In order to prevent muscle turbidity of Macrobrachium rosenbergii in horizontal transmission, strict management system of nursery area can be formulated. The main contents are as follows: ① Nursery staff operate in strict accordance with the operating rules of Macrobrachium rosenbergii culture, and disinfect the tools used in culture in time. There should be a disinfection pool at the entrance of the workshop, and personnel should be disinfected at any time when entering and leaving the workshop. ② Before entering the workshop, customers who buy seedlings should disinfect their shoes and hands. It is forbidden for customers who buy seedlings to contact water and shrimp seedlings. When it is necessary to see the seedlings, the workshop manager will operate them on their behalf. Don't rush to buy seedlings, which will lead to skyrocketing seedling prices, increase breeding costs, and prevent the phenomenon of "high price, poor quality and insufficient quantity";

It is necessary to strengthen the greenhouse to prevent the damage caused by strong winds and heavy rains;

Choosing high-quality shrimp seedlings is the key. It is necessary to choose neat shrimp seedlings with strong physique, complete metamorphosis, desalination in place and reasonable price;

Create a good environment for shrimp seedlings to enter the shed. Introduce an appropriate amount of high-quality water source, adjust water quality and control water temperature;

Strictly do a good job in testing water for shrimp seedlings. Should be directly put into the pool with a net bag for at least 24 hours;

Master the temperature difference of shrimp seedlings entering the shed. It is necessary to put the purchased shrimps safely into the temporary shed at the first time, and put them into the shed in time when the temperature difference between the water in the bag and the water in the shed is about 2℃. When planting seedlings, put them evenly around the shed, not just at one point.

Do the daily management after stocking;

Master the temperature in the shed. The temperature is controlled at around 26℃ in the morning and evening, and around 30℃ at noon. At the same time, pay attention to ventilation and light transmission at noon on sunny days to prevent seedlings from being burned by high temperature. Pay attention to the temperature: Macrobrachium rosenbergii larvae can only be cultured in the pond when the water temperature in the pond reaches above 22 degrees for three consecutive nights.

Climate change: pay attention to weather change. In case of continuous rainy and cold weather forecast, it is necessary to expand water carefully, and it is best to postpone the expansion time to prevent seedlings from being damaged by low temperature.

Pond water injection: When injecting water into the pond, attention should be paid to the entry of enemy creatures and wild fish, and strict screen filtration should be carried out. The initial water addition should not be too deep or too shallow, and the water depth should be controlled at about 60cm, and then the water level should be gradually increased.

Apply base fertilizer: apply base fertilizer 4-5 days before seeding. Organic fertilizer must be fermented before use, and the dosage should not be too large, and the transparency of pond water should be about 35cm. If urea is used, it must be soaked for more than 2 days before it can be poured into Datang.

Inverted pool counting: When water is amplified, inverted pool counting is required. Generally, there are about 40,000-50,000 shrimps about 3cm per mu. 1. Cultivating virus-free parent shrimp is the key. The breeding technology of virus-free seedlings of Macrobrachium rosenbergii can effectively prevent the occurrence of muscle turbidity disease, and the key lies in whether it can effectively block the transmission route of pathogenic bacteria. The epidemiological investigation of Macrobrachium rosenbergii muscle turbidity disease showed that its main transmission route was the carrying and transmission of parent shrimp. By tracking and detecting the parent shrimp fry, isolation measures were taken in the whole breeding process to fully ensure the virus-free state of the selected parent shrimp.

2. The intensive cultivation of parent shrimp and suitable environmental conditions in the production process are the auxiliary measures to cultivate virus-free fry. Pathogen, shrimp and environment are an interactive and interrelated system. Normally, they are in a balanced system. The change of one of them will inevitably lead to the imbalance of the whole system and the occurrence of diseases. The epidemiological investigation of muscle turbidity disease of Macrobrachium rosenbergii also verified this point. Therefore, strengthening the nutrition of parent shrimp and adding vitamins, immune polysaccharides and other substances in the feed can effectively improve the physique and immunity of parent shrimp. In addition, suitable environmental conditions should be ensured during larval culture.

3. In order to prevent muscle turbidity of Macrobrachium rosenbergii, strict disinfection measures must be taken. Strict disinfection measures are an important guarantee to prevent diseases. Almost all the breeding grounds of Macrobrachium rosenbergii are built in epidemic areas, and disinfection measures are the key to ensure that the breeding grounds are not infected by adjacent epidemic areas. The seedling workshop strictly implements the disinfection system of appliances, and takes necessary measures for customers who buy seedlings to restrict customers from entering the production area, while customers only enter the seedling supply area. All personnel entering the production area must strictly disinfect their hands and shoes to ensure that they do not carry viruses into the production area.