Management of broodstock before winter
1. Moderate holding: There is a holding stage in the middle of the wintering between broodstock and entrants. Select high-quality cultivated shrimp that meets the requirements, and the individual is large and robust, to be raised and kept for broodstock use. The length of the resuscitation period depends on the conditions and climate of each place. Due to water temperature, copulation and other reasons, broodstock entrancing time is generally later than the shrimp pond fishing time, so every year in October should be selected from a good cultivating pool into a special holding pond for temporary raise. The temporary storage ponds should be dug off the surface silt first, clear the pond with lime, and expose the sun; the bait must be of sufficient quality to make the shrimp into a sturdy body before entering the room through winter; change the water once a day, fresh water quality; maintain a certain water level to avoid drastic environmental changes and Because the shrimp body is exposed to light, the body shells of the shrimp body are attached to the algae. When the broodstock in the holding pool is drastically declining, when the water temperature drops sharply, it will quickly enter the peak period. At this time, attention must be paid to listening to the weather forecast, paying close attention to climate change, making preparations for wintering in advance, and preparing to enter the room at any time.
2. Strictly choose to keep broodstock: The artificially overwintering should be performed with selective glandular fullness, individual largeness, no injury, no illness, and robust broodstock. From cultivation pools to holding pools, holding pools to indoor wintering pools, these three links must be selected again and again.
3. The broodstock overwintering pool, tools 500 ~ 800PPM bleach or 10 ~ 15PPM potassium permanganate disinfection.
4. Be extra careful in the selection and transportation operations to prevent injuries. Fishing tools and ponds should be clean and clean.
5. The treatment of water during the wintering period is based on the requirements for the treatment of shrimp water for nursery.
6. Timely feeding of broodstock: There are many disadvantages for broodstock to enter the overwintering room prematurely. First, shrimps have poor indoor mating effect. Second, the water temperature is too high. After the prawn enters the room, it is easy to molting. Third, the indoor wintering time is too long. Weak constitution and easy to get sick. However, when they enter the room too late, they are often caught off guard by the sudden attack of cold air.
Thermoplastic starch is also called "non-structured starch", which can make the starch structure disordered and thermoplastic by certain methods. Starch molecules for polysaccharides molecular structure, containing a large number of hydroxyl, due to its intermolecular and intramolecular hydrogen bond action, so that its melting temperature is higher, and its decomposition temperature is lower than its melting temperature, so in the heat processing, starch molecules did not melt and first decomposed. The traditional mechanical processing method of plastic is mostly heat processing, so to make starch - based whole starch plastic needs to make natural starch thermoplastic. This thermoplasticity can be achieved by changing the crystalline structure inside starch molecules. Destroy intramolecular and intermolecular hydrogen bonds, disrupt the double helix crystal structure of starch molecules, which will reduce the melting temperature of starch and make it thermoplastic.
Starch-Based Plastics,Cellulose-Based Plastics,Protein-Based Plastics,Some Aliphatic Polyesters
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