Turbot breeding techniques
Turbot is a valuable halibut native to the European coast. Since its introduction in the Yellow Sea Fisheries Research Institute in 1992, it has become an outstanding aquaculture species in northern China with its unique high growth rate, excellent quality and strong disease resistance. The main object of factory farming. However, because of its difficult propagation, low survival rate and high rate of bleaching, it has restricted the further development of turbot industrial aquaculture. Rizhao City, Shandong Province, Tongxiang turbot workshop has been based on the expert's classic theory in combination with its own operational innovation, has achieved more than 10% survival rate of turtle seedling survival rate, the primary color rate of more than 80% of the results, will now The technical experience is briefly described as follows: Turbot fertilized eggs were fully washed in eggs and were sterilized in a 30 ppm PV iodine solution for 15 minutes. They were then placed in a special incubator or hatching cage to hatch. The hatching density was generally about 200,000 grains/m3. According to experts, water temperature of 13°C is suitable for the storage of yolk nutrients, which is not easy to cause the waste of yolk, so the incubation temperature is generally controlled at 13°C. The water exchange capacity is 2 times/day to 2.5 times/day, the light intensity is 400 lux to 700 lux, and the aeration is maintained in a microwave. When the hatching cage is used, it is inflated outside the tank and the aeration amount is appropriately increased. During the incubation process, the dead eggs are cleaned every 24 hours to avoid damaging the water. Second, seed cultivation Turbot can be hatched at a water temperature of 13°C for 110 hours to 120 hours, and then transferred to a seedling cultivation pond in time after emergence. Specification for the cultivation pond: 1 m2 to 3 m2, 0.6 m deep, square The seedling density is 20,000/m3 to 30,000/m3. Into the seedlings began to increase the water temperature 0.5 °C every day, to maintain stability at 15 °C, can maintain the best utilization efficiency of the yolk, and then increase the amount of water, up to 3 times / day ~ 5 times / day, generally keep the daily suction 2 Times, the light gradually increased to 1000 lux to 2000 lux. The seedlings within 6 days of age are still in the endogenous vegetative stage. At this time, no baiting is allowed, and appropriate amount of chlorella can be added to maintain the slightly green state of the culturing water body. At this time, the newly hatched larvae have a weaker activity and do not need to be inflated to maintain the microwave state. After 6 days, the yolk sac has shrunk and the yolk has been basically consumed. The larvae begin to be transformed from endogenous nutrients to external nutrition. The water temperature is gradually raised to 17°C in 4 days to 5 days, and kept to the seedlings. End. Timely input of nutrient-enriched rotifers for fry feeding, feeding amount between 5/ml and 10/ml, at this time larval intestine has been opened, metabolic material has been excreted, in order to keep the water fresh and clean, increase the exchange The amount of water is 6 times/day to 10 times/day, and the management of sewage suction on the bottom of the pool is strengthened. During this period, the larvae were very delicate and the aeration was still microwaved. The 6th to 8th days after hatching is the critical period of feeding management. If there is insufficient supply of bait, it is difficult to successfully complete the transformation of endogenous nutrients from external nutrition. At this time, 10 individuals/ml of rotifers in the water body are generally maintained. According to our experience, on the 8th to the 9th day before retrieving, appropriate reduction in the amount of feeding and reducing the density of rotifers to 5/ml or less is good for the diet. It is estimated that it may be reduced to feeding with larvae. The tube leaves a lot of space. Around the 9th day of opening, it means that a large number of larvae have been eliminated. At this time, the mortality rate is generally about 80%. This is the period when the loss of turbot larvae is the most serious. In the following 2nd to 3rd days, some larvae that died out of synch also gradually died, but the mortality rate was not very high. Generally, they gradually stabilized after the 12th day, in order to keep the water quality in the cultivation pond clean and prevent the dead individuals from being cleared. The pool should be poured in due course and the cultivation density should be adjusted to 1500/m3 to 2000/m3. With the opening of the fistula, the larvae changed from "red seedlings" to "black seedlings" and began to feed on Artemia nauplii, while maintaining 10/ml rotifers while adding 1/ml Artemia nauplii, due to The increase in larval activity and the increase in dietary organisms in the water, it is necessary to increase the amount of aeration, and it is generally more appropriate to reach a wavy shape. From the 15th to the 18th day of age, as the body of the larvae gradually becomes bolder, the domestication of the compounded bait is started, and the rotifer feeding is gradually reduced. The preliminarily domestication of feedstuffs is generally performed at night, and they are fed at 20:00, 22:00, 24:00 and 6:00 respectively. They are fed twice a day, about half an hour each time, and after 5 days to 7 days, fry can be achieved. All foods are fed together with the bait, and the sewage is collected in a timely manner after the feeding to prevent the remaining bait from contaminating the water quality. In order to prevent incomplete conversion of the individual fry bait, generally 0.5/ml Artemia larvae were kept until the 4th week. About 3 weeks to 4 weeks after hatching, the fish body was widened and thickened, basically completing the appearance and internal structure metamorphosis, and entering the juvenile stage. With the combination of pigment development, the body color also turns from black to a fluorescence-like spot, and the fry changes from “black seedlings†to “flower seedlingsâ€. At this time, it begins to gradually decrease until the feeding of Artemia nauplii is stopped. Cast with bait. In the 5th week, the shape of the fish has basically approached that of the adult fish, that is, it enters the juvenile stage and continues to grow until it reaches the product seedling pool. In juvenile and juvenile fish rearing stages, the seedling density is appropriately adjusted according to the growth of the fry, and the final density of the 5 cm commercial seedlings is below 1000 fish/m3, and the bait grain size is adjusted at the same time, from 250 μm to 400 μm at the beginning of domestication. By the later period of 0.8 mm to 1.0 mm, the physical strength of the fry gradually increased, and the inflation was also adjusted from wavy to slightly boiling, and the amount of water changed was also increased by 15 times/day to 20 times/day. Third, the nutrition of food organisms The larvae and Artemia nauplii are required for opening and pre-feeding of turbot fish seedlings. Both of these biological feeds lack nutrients such as EPA and DHA that are necessary for the early development of fry, so they must be fed before feeding. To strengthen the nutrient, it is very good for the survival rate of the turbot especially the increase of the primary color. Fourth, the use of water treatment We are more careful about the use of water for nursery and more strict water use before reclaiming. The seawater that is normally stored in the severe winter season is filtered by a sand filter well and then pumped into a sedimentation tank. After a week of sedimentation, it is filtered by a sand filter and a cotton absorbent before it is used for the hatching of turbot eggs and the cultivation of “red seedlingsâ€. Afterwards, the water is also filtered and precipitated three times. This basically ensures that the water quality is clean and the organic impurities and protozoa are isolated. We think this is an important part of the breeding of turbot. V. Disease Prevention In addition to the strict treatment of water, the elimination of protozoa infections and the prevention of bacterial infections are also critical for the prevention of diseases because the water is continuously changed during the entire cultivation process. If the drug is applied directly in the cultivation pond, it is difficult to grasp the drug concentration. In order to accurately use drugs and prevent drug use accidents, we apply sedimentation tanks to collect a pool of water for 3 days and then apply ofloxacin 2ppm or florfenicol 1.5ppm to sterilize them, and then introduce them into the nursery room and bait room for use. After the pool water is used up, the pool is brushed cleanly and the water is applied again, which can maintain the stability of the drug concentration in the water used for the cultivation of the vaccine to achieve the purpose of disease prevention. Dried Zucchini Powder,Zucchini Powder,Freeze Dried Zucchini Powder,Dehydrated Dried Zucchini Powder Ningxia Lihe Food Co., Ltd. , http://www.lihedried.com
First, the incubation of fertilized eggs