The best season for crayfish farming is here again. What should you pay attention to when raising crayfish?

Large size, good appearance, early on the market and late on the market are the comparison standards for the efficiency of crayfish farming, and are also a watershed in farming technology. At present, crayfish farming mainly includes three farming modes: rice field shrimp farming, pond intensive farming, and shrimp and crab mixed farming. Taking intensive pond farming as an example, 6,000-8,000 seedlings are released per mu. The crayfish output is generally 200-300 catties/mu. , the average size is calculated based on 6 yen, and the survival rate is less than 60%; although some have high survival rates, the crayfish sizes are low (4 to 5 yen), and their economic value is not high, which is another factor that causes farmers to not make money.

Based on many years of experience in serving the front line of aquaculture, the author analyzed that the main reasons for the low survival rate and small size of crayfish farming are as follows.

1. Environmental deterioration

Crayfish are intensively cultured at a high density, there are many aquatic plants, and the amount of feeding is large. The fertility of the water body will inevitably increase, which can easily cause algae infestation and algal toxins from dead algae. It can also cause harm (because cyanobacteria are resistant to high pH, ??the algae-deficient environment after algae removal can easily become a breeding ground for cyanobacteria to explode); due to large amounts of feeding, usually in a high-nitrogen environment, the sharp increase in hydroxyl radicals will cause more ammonium to be released. The ions combine with it to form molecular ammonia, causing the concentration of molecular ammonia to soar and causing ammonia poisoning. Under the stress of water environment with high pH value, high ammonia nitrogen and high chlorine preparation residue, it will cause damage to the hepatopancreas of crayfish. The hepatopancreas is an important organ for crayfish to absorb nutrients, immunity, and detoxification. Once the disease is damaged, in mild cases, the crayfish will not be able to absorb nutrients normally, and its growth will be affected, resulting in smaller individuals. In severe cases, the crayfish will not be able to shed its shell. , or even death. ,

2. There are many anti-nutritional factors in the feed

Crayfish are omnivorous animals. Generally, plant raw materials account for about 60% of the feed, and animal raw materials account for about 40%. The author's investigation in Qianjiang, Jianli and other places in Hubei Province found that the local crayfish feed protein ranges from 25 to 30 yuan, and the price ranges from 3,000 to 4,000 yuan/ton. This will inevitably lead to the use of too much plant-based protein in the feed, resulting in There are too many toxic and harmful substances such as soybean trypsin inhibitor (soybean meal), glucosinolates (vegetable cake), and aflatoxin (peanut meal) in the feed. When crayfish eat this kind of feed for a long time, it will cause lesions in their liver and pancreas, resulting in slow growth. In severe cases, it will cause low immunity and disease outbreaks.

So, how to improve the output, specifications and quality of crayfish farming?

The first is to maintain stable water quality.

When disinfecting, try to use iodine preparations and avoid using chlorine preparations that are easy to remain; add phosphate fertilizer in time according to the water color, in small amounts and multiple times, so that the nitrogen-phosphorus ratio reaches a reasonable range and stabilize beneficial algae (green algae, silica) in the water body. algae) reproduction to reduce the outbreak of blue algae; turn on the aerator regularly to ensure sufficient dissolved oxygen in the water body.

The second is to feed high-quality bait.

Feeding high-quality feed with high protein content and rich nutrition in a timely manner according to the water temperature, appropriately supplementing the nutrients required for the growth of lobsters will help them to focus on smooth shelling, timely recovery of physical fitness, and accumulation of nutrients.

The third is to do a good job in the health care of the liver and pancreas of crayfish.

Regularly adding bile acids to crayfish feed can help the health of the liver and pancreas, promote the absorption and utilization of nutrients in the feed, especially the absorption of cholesterol, so that crayfish can shed their shells and grow smoothly. weight gain; enhance the detoxification and detoxification function of the liver, assist the liver in expelling toxins from the body, and indirectly improve immunity and survival rate.