The purpose of breeding broodstock larvae is to make the ovaries of prawn larvae grow in a basically synchronous manner, spawning and larvae are discharged neatly, and a large number of false larvae can be obtained to form a certain scale of production.
1 Conditions for cultivating the pool There are two kinds of broodstock breeding ponds, one is an indoor pool and the other is an outdoor pool. The indoor pool is mostly a concrete pool with an area of â€‹â€‹20-60m2/water depth of about 1.5m. The bottom of the pool is covered with sand of about 10cm. Artificial caves need to be laid. Generally, polyethylene and polypropylene pipes are used, and bamboo bamboo pipes can also be used. Open up the section, length 40-80cm, diameter 6-10cm. The number of burrows is 1.2-1.5, which is believed to be the number of broodstocks. It is also necessary to add oxygen to the pool to increase oxygen. Before use, sand and pipes must be washed. The whole pool should be disinfected with 200 X 10-6-300 X 10-6 bleach powder. Only when the medicinal property is replaced with fresh seawater, can the shrimp be placed in the broodstock.
The outdoor pool is generally land, with an area of â€‹â€‹200-2000m2/basis, pond embankment height of 2.0-2.5m, water depth of 1.5-2.0m, convenient drainage and drainage, and can drain pool water. The bottom of the pool should be soft and soft, so as to facilitate the inhabitation of the shrimps, hold eggs and hatching, but the bottom of the pool should not be too much, and it should be less than 20cm, and there should be no black saprophyte. Days or so, clear the pond with lime, disinfection, the amount of 75-100kg/mu. It can also be disinfected with bleach, at a concentration of 200 X 10-6.
In order to prevent broodstock snakes from escaping with water or lake water and larvae of shrimps wading in order to escape the water, dense nets must be installed at the entrance and exit points; pests can also be prevented from entering the water outlet and eating shrimp larvae.
The two cultivation ponds have different characteristics in broodstock snake cultivation. The area of â€‹â€‹outdoor earth ponds is large, and the number of stocked shrimps is large. This is similar to the natural environment of shrimp shrimp, which is conducive to incubating eggs with brooding snakes, and the survival rate of broodstock breeding. Higher, generally well-managed, survival rate of up to 85%, but the water temperature is not easy to control. Indoor pool area is small, water level, water quality, water temperature is easy to control, broodstock hold eggs hatching time can be artificially controlled with the needs of production, larvae discharge is relatively neat, relatively easy to set seedlings; but human influence is greater, broodstock turtles susceptible to mechanical Injury and disease, easy to fall off when hatching eggs, the survival rate of broodstock breeding is slightly lower.
2 The selection of shrimp broodstock
2.1 Types and sources The current species of artificial breeding of mantis shrimp are reported only in the black-spotted shrimp and white-shouldered shrimp. In addition, spiked shrimp snakes, spiny horned shrimp, and spotted shrimp are also good varieties. The source of broodstock bream can be selected from farm ponds or low dam high nets and can also be caught in natural sea areas. The direct acquisition of cultured shrimp from farms results in short time to water, good development of gonads, and good quality; shrimp caught in the sea is mainly captured by fixed nets and bottom trawls, and small amounts are captured directly from mudflats. , often with injuries, need to carefully select the brood shrimp.
2.2 Identification of male and female shrimps Shrimp larvae with a body length of 5crn or more are well matured. The main difference between male and female prawn larvae is the final pair of step and foot male and female shapes on the chest. The male has a pair of rod-shaped connectors on the inside of the foot pedestal. However, females are not; the second lobe (flooding) of male broodstock is significantly larger than that of females. The female snakes that have been mated have, on the ventral surface of the 6th to 8th thoracic nodes, a "king" shaped colloid gland that is milky white and its color is gradually milky as individual gonads mature. When you select the shrimp, turn it over to see.
2.3 Quality and Specifications When purchasing broodstock, we must choose a shrimp prawn that is short in water, strong in body, full of appendages, free from scars, strong in activity, bright in color, and more than 30g in weight and 11cm in length. In addition, choose to mate. Females with well-developed gonads act as broodstock snakes. The female snake with good gonadal development, from its ventral surface, can see an orange gonad (commonly known as cream) extending from the chest to the tail section. The thicker the paste, the darker the color, the better the gonadal development; When the tail section is triangular, females will spawn within a week. Individual large broodstocks produce large amounts of eggs, and males with body lengths of 11crn and above each produce 0.8-3 million eggs per year.
2.4 Acquisition and cultivation time Since the shrimp oviposition and breeding season is from April to August, the acquisition time is usually before 2-5 months; it can also be acquired before the end of the previous year, and it will be stored in the broodstock pond in winter. . Because the mating time of shrimp mantis is generally in the fall of water temperature 15Â°C-20Â°C and some springs when the water temperature rises above 15Â°C, so choose the mated female snake as the broodstock, do not need to purchase male shrimp again. Hey. This will not only save costs, but also reduce the interference of male puppies in the process of hatching of female snakes.
3 When broodstock puffers are stocked and broodstock are shipped, special attention should be paid to the temperature difference during stocking. The required temperature difference should not exceed 3Â°C and the salinity difference should not exceed 5 â€°. The stocking density of broodstock larvae is 5-10/m3 in indoor pools, and 2-3/m3 in outdoor soil pools. If artificial burrows or concealed objects are placed in earthen ponds, the stocking densities can be appropriately increased.
4 daily management
4.1 Water quality management Keep fresh broodstock snake pond water quality, dissolved oxygen above 5ml/l. Change water 1/3-l/2 daily, slightly more indoor pool, remove excess bait when changing water. Outdoor transparency is controlled at 30-50cm or more. In summers with higher temperatures, pool water level should be increased to prevent the water temperature from being too high, affecting the hatching and hatching of the broodstock, and even causing death. During cultivation, the outdoor soil pool uses lime water to improve water quality and sediment quality every 10-15 days, and indoor plants should also be regularly applied to prevent disease.
4.2 Water temperature management Shrimp snake is a wide-temperature organism, the most suitable temperature for growth is 20Â°C-28Â°C, and the optimum breeding temperature is 24Â°C-28Â°C. The water temperature of the outdoor pool changes with the change of temperature and is not easy to control. Conditional units can cover plastic film greenhouses on the pool, which can slightly control and relieve sudden changes in water temperature and salinity caused by sudden changes in the weather. Indoor pool water temperature is easy to be controlled, according to production conditions, appropriate increase in water temperature, early breeding seedlings production.
4.3 Feeding management shrimp diets are dominated by animal foods and can be eaten on fish, shrimp, shellfish, etc., but fresh, low-value shellfish such as Yazui can be better, which can avoid polluting the water quality and sediment quality. . In order to facilitate hunter-feeding and prey-reducing feeds, it is necessary to cut small pieces of bait when feeding large individuals, such as mixed fish, and evenly distribute them when feeding, in order to facilitate the feeding of shrimp and improve the utilization of baits, and also to prevent them. Kill each other. Shrimp clams have habits of nocturnal activity and feeding. It is advisable to feed them in the evening and feed them once a day. The amount of bait is 5% to 20% of the total weight of the crawfish, and it is accompanied by the size of the shrimp. High and low, weather conditions, food types, quality conditions, etc. vary.
In the early stage of broodstock breeding, because the broodstock has not spawned yet, it is in urgent need of food nutrition to provide gonadal development. The broodstock snake has a large food intake, and the daily feeding amount is 10%-20% of the total weight; during the middle period of cultivation, the feeding is gradually reduced. Quantity and daily feeding amount are controlled within 5%. In the middle and late stages of breeding, broodstock with hatched larvae gradually increase after spawning and the food intake will increase. In addition, when the water temperature is lower than 15 workers or higher than 33Â°C, the food intake of shrimp snakes is obviously reduced. At this time, the food should be less or not.
4.4 Inspecting ponds (pools) Inspecting ponds (pools) Observe the activities and feeding conditions of the shrimps, especially the parental discharge of larvae. Record after each pond (pool) inspection. Find problems and deal with them in time. In the indoor area, you can also use a beaker to take water samples to check whether the broodstock has discharged larvae. Once you find that the broodstock has been discharged, you will be able to release false foods. Alcohol, shisha, apricot, and apricotå‰æž³ å‰æž³ (14) é¦“ç‚± æµ æµ éº“ç¬¥æ˜Šå´¾ éº“ç¬¥æ˜Šå´¾ éº“ç¬¥æ˜Šå´¾ K K K K æˆŽäº 10 10 10 10 10 10 (10) æˆŽæž æˆŽæž ? æ±• æ±• æ±• å€™
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