Young hatchlings are relatively delicate, weigh only 3-5 grams, and have poor foraging ability and disease resistance. If put directly into the pond for breeding, the growth rate is slow, the mortality rate is high, and it is easy to infect the disease and suffer the invasion of the enemy. Therefore, larvae must be intensively cultivated after being hatched and carefully fed to increase the survival rate. Scientifically feeding newly emerged juveniles should not be collected and cultivated immediately. They should be kept on the sand table or in shallow water basins for 2-3 days, and then transferred to the nursery pond for cultivation. Stocking density is 40-50/m2. Three days after hatching, the yolks in the body have been absorbed and they begin to ingest food. First of all, we should use special feed for juveniles, which requires fine, soft, no rot and mildew, complete nutrition, and good palatability. More than 46% of the feed protein content of pollution-free green full-priced compound feed. Feeding should adhere to the "four principles" principle, so that juveniles develop a regular, positioning eating habits. The high temperature season can be divided into two feedings in the afternoon and one in the autumn. The feed should be put on the feed table. The amount of feed can be controlled flexibly according to the weather, water temperature, growth and eating conditions. Generally, it is advisable to eat in 4 hours with no surplus. In the case of water temperature 25-30 °C, the feeding amount should account for 2-5% of the juvenile weight. Food cleaning should be performed before feeding every day to prevent contamination of new feeds and contamination of water quality. Scientifically diverting water and changing water Some people think that if you use lungs to breathe, the quality of water has little effect on the growth of earthworms. Actually, although it is lung respiration, most of the time it lives in water, so water quality Good or bad will directly affect the growth and survival rate of juveniles. The young fish pond is small, the water is shallow, the depth of the water storage is only 30-40 cm, the stocking density is high, and the water quality is easily deteriorated. Therefore, the water should be replaced once every 3-5 days, and the amount of water is changed every time. About 1/3 is appropriate, the temperature difference when changing the water should not exceed 3°C. A small amount of floating plants such as water lettuce can be placed in the cultivation pond. The first is to improve and purify the water quality; the second is to allow the juveniles to inhabit, conceal and reduce the biting of the juveniles, which can play a role in disease prevention. The use of biological agents to control water quality, generally every 10-15 days with photosynthetic bacteria, nitrifying bacteria, Bacillus and other biological bacteria spilled, improve water quality; using bio-bottom improver to improve the pool bottom environment. Scientific disease prevention and disease prevention should adhere to the principle of "prevention first, prevention and control combined". One is ecological prevention; the other is drug prevention. Ecological disease prevention is to improve the ecological environment and water environment of the juvenile culture ponds, and to scientifically feed baits, control the stocking densities, and use the mutually beneficial relationship between the populations of earthworms and aquatic plants to create a good breeding ecological environment; drug prevention is just before stocking. To sterilize the cultivation pond and nursery fish, the operation method is to use 250-300 grams of lime for each cubic meter of water or 25-30 grams of bleach for 30% chlorine, disinfect the cultivation pond, and dispose of the pool water after disinfection. , Let the sun exposure for 2-3 days, then introduce fresh water and then put the seedlings. Before juvenile pooling, use 3-5% salt water to bathe for 20-30 minutes to kill harmful microorganisms and prevent bacteria from entering the pool, which can play a role in preventing disease. With the rapid growth of juveniles, individuals of different sizes should be fed in a timely manner in order to avoid snipes robbing them of food, leading to hunger and weight loss, reducing juvenile disease resistance and immunity, causing disease and death. In short, the prevention of juvenile deterrence should be based on prevention. From the viewpoint of improving the ecological environment, water environment, controlling pathogens, and combining scientific management measures, the purpose of disease prevention can be achieved.
Raw Material Powder,Extract Raw Material,Raw Material Extraction,Cosmetics Raw Materials
Xi'an JCF Herb Technology Development Co., Ltd , https://www.jcfherb.com