Artificial breeding trials have been reported several times in the country. This article uses existing facilities under production conditions, using pro-Betti early ripening, dry and flowing water to stimulate spawning, reasonable selection of attachment base particle size and bait species, and feeding methods, plus The exchange of water and other measures to obtain fertilized eggs 4 million, cultivation of 3.5 million D-type larvae, eye larvae 2.5 million, out of the pool 650 to 950: μm juvenile 1.8 million. ??
1 Materials and Methods?
1.1 Test conditions The experiment was conducted in the shrimp nursery room in Nantang Town, Yueqing City, Zhejiang Province. The test water body was 600m? 3, including 400m? 3 of the nursery water body, a total of 10 identical cultivation ponds; and the bait cultivation water body 200m? 3, totally 20 Incubate the pool. The water supply system adopts secondary sedimentation and water supply through the high-level pond sand filter. Two Roots blowers were used to rotate continuously and the gas stones were evenly placed at the bottom of the pool. Adjustments were made to keep them evenly inflated. Indoor light control is 800 to 1000 lx. The salinity is between 24 ‰ and 26 ‰, the water temperature is 28 32 32 °C, and the pH value is 8.2 8.6 8.6. ?
1.2 test method?
1.2.1 Pro-Bedding Breeding pro-Belgium was collected from the sea near Nantang Town, Yueqing City. In April, it was moved into the outdoor earthen ponds for fattening by means of feeding or changing water. A total of 10kg of pro-Bacillus was raised in an area of ​​0.33 hm?2. In the earthen pond. During the holding period, depending on the water quality, the water is exchanged between 1/4 and 1/3 a day, inoculated with gold algae and Platymonas, and the density of unicellular algae in the water body is maintained. In late June, 5 to 7 days before spawning, the animals were moved to the indoor cement pool for intensive cultivation, aerated, changed water 1/2 to 1/3 daily, and the feeding amount was 150,000 cells/ml. The incubation temperature was 24 to 26°C.
1.2.2 Egg-laying hatching Inspect the development of pro-occlusion gonadal glands. When most of the individual gonads are mature and mature, select 15kg individuals with robust individuals and shell lengths of more than 2.5cm to wash and disinfect, and soak for 10 minutes with (5～10)10-6 KMnO?4. After rinsing and drying, 4 hours later, the pro-beehives were evenly spread on a rectangular spawning bed woven with bamboo strips and placed flat on the bottom of the spawning pool. The spawning bed specifications are 1.5m1.0m. Open the inlet valve and drain valve of the hatching tank, and use the water pump to flush water horizontally into the wall of the inlet, so that the water flows evenly through the egg-laying bed to stimulate the pro-shellfish. After the pro-Bet emission of eggs, lift the egg-laying bed up to about 20cm from the water surface and pick out male individuals in time to reduce excess semen. After the discharge is completed, the egg-laying bed will be removed, the pool water will be filled, and the egg will be left standing for about 30 minutes to settle. Then the upper water will be discharged through the egg-washing drainage hole and the siphon method, and the water will be filled up again, and the egg washing will be repeated twice. Excess semen and dead eggs, etc., to ensure that the hatching water is clean. Open the air valve and adjust the amount of air bubbles and aeration to match the water quality of the hatchery. ?
1.2.3 Cultivation of larvae Before hatchery spawning, the hatching pool is sterilized with 20,000 international units of penicillin and 40,000 international units of streptomycin, then filled with water and inflated. After the egg is washed, the fertilized eggs are transferred to the hatching pond for incubation. The hatching density is controlled at 30-40/ml. When the larvae develop into platter larvae, the juveniles are bred and divided into pools. The upper larvae and lively larvae are further transferred to the sterile water-inoculated culturing tanks with 200 mesh nets, and the culturing density is 5-8/ml. When the larval gut is formed and the digestive organs are well developed, feeds are started. The types of bait are mainly single-celled algae such as Chaetoceros muelleri, Chlorella, Isochrysis galbana, and Forsythium sp. Using forked algae and Isochrysis galbana as the open bait, the daily feeding amount was 20,000 cells/ml. Later, as the individual increases, the amount of feeding gradually increases. When the larvae developed to the shell top stage, Chlorella vulgaris and Platymonas subtilis were added, mixed and fed, and the feeding frequency and feeding amount were appropriately increased depending on the feeding condition of juveniles. When the food is insufficient, it is supplemented with a small amount of active yeast. ?
When the larvae reach the metamorphosis stage, beach mud scraped from the nearby sea area, scraped and screened (with a particle size of 50 to 100 μm) is deposited as an attachment base in the attachment pool, and the mud is spread evenly on the bottom of the pool. , stop inflating. After the precipitation, the small amount of gas is inflated, and the amount of gas is preferably not to stir the sediment. The 300-mesh gill net was used to move the larvae into the attachment pool to increase the amount of water exchange and feed. The daily water exchange rate is 100% to 300%, and the daily feeding amount is maintained at 40,000 to 60,000 cells/ml. After the larvae have developed into juveniles, they are poured once every 5 days. The cultivation density is 800,000 to 1 million/m2. ?
With the development of larvae, the amount of bait was gradually increased, and gold algae, Platymonas and Chlorella were mixed and fed. After the larvae became abnormally attached, the daily feeding amount increased to 50,000-60,000 cells/ml to increase the larvae's demand for various nutrients. ?
Face plate larvae initially added 10 cm of water every day. As the individuals grew, the water was changed 1/2 per day, and the amount of water changed to 2/3 of the day before the shell top changed. After the larvae were transferred to benthic life, the amount of water changed every day was 100% to 300%. ?
2 results?
2.1 Promatite maturity The 2nd to 3rd-age loach selected from the natural sea area 3 months before the nursery was raised and strengthened in an outdoor earth pond, and was continuously observed with the muddy loach collected in the natural sea area, and was raised and maintained. The fertility and gonad maturation of the intensively cultivated pro-family were significantly better than those of pro-shellfish harvested in the natural sea area. ?
2.2 Egg-laying Incubation of dried pro-scallops, after 20 minutes of flowing water stimulation, sperms and eggs are gradually discharged. The male semen is white silky, and the female eggs are gradually discharged from the light yellow smoke. The emission duration is about 40 minutes. The fertility-producing pro-shellfish spawning rate is about 37%, and the average individual egg production is 2.5 million. The hatching density of each pool was controlled at 30-40/ml. Under the conditions of water temperature of 30～32°C and salinity of 24 ‰～26 ,, the first polar body appeared at 9 min of fertilized egg and developed to face plate larvae at 16 h. The average fertilization rate was 98%, and the average hatch rate was 89%. ?
2.3 The larval reared the larvae for about 14 days and developed the eyeballs to the metamorphosis stage. The survival rate of the platter larvae to metamorphosis was 69%, and the adherence rate was 35%. Out of 650 to 950 μm of juveniles, 609,000 grains/m2, juveniles have an area of ​​300 m2, and a total seed production of 180 million grains. ?
3 Discussion and summary?
3.1 Probation and cultivation of pro-shellfish is an important technical link in shellfish breeding. Artificial bait, water change and other measures are adopted. Intensive breeding of pro-scallops is promoted in advance to promote the development of pro-occluded gonads and a large number of high-quality eggs can be obtained. Effective measures for spawning rate and hatching rate. 3.2 Use of spawning beds to mobilize water can prevent water pollution. Use spawning beds to mobilize can adjust the height according to need, pick out male individuals in time, reduce semen in water body, remove pro-bellied one-time, and prevent water pollution. ?
3.3 Use of washing hole and siphon method to remove upper layer of water can avoid damaging eggs. Under the production conditions, using egg washing hole and siphon method to discharge the upper layer of water can also achieve the effect of washing eggs repeatedly. In particular, a large area of ​​breeding requires a large number of fertilized eggs. When using this method, you can avoid egg damage. ?
3.4 The bait is an important factor influencing the development of the larvae. Poor feeding or a single type of bait can cause slow growth of larvae. Individual development is uneven, and due to lack of nutrition, not only the survival rate is low, but also susceptible to disease. All kinds of bait with mixed feeding, keep the density of unicellular algae in the water at any time is an effective measure to improve the survival rate of nursery. ?
3.5 Maintaining fresh water can promote the development of larvae. Muddy larvae have higher water quality requirements, increase exchange of water bodies, reduce the content of organic matter such as baits and feces in water bodies, and promote the growth and development of larvae and increase the survival rate.
1 Materials and Methods?
1.1 Test conditions The experiment was conducted in the shrimp nursery room in Nantang Town, Yueqing City, Zhejiang Province. The test water body was 600m? 3, including 400m? 3 of the nursery water body, a total of 10 identical cultivation ponds; and the bait cultivation water body 200m? 3, totally 20 Incubate the pool. The water supply system adopts secondary sedimentation and water supply through the high-level pond sand filter. Two Roots blowers were used to rotate continuously and the gas stones were evenly placed at the bottom of the pool. Adjustments were made to keep them evenly inflated. Indoor light control is 800 to 1000 lx. The salinity is between 24 ‰ and 26 ‰, the water temperature is 28 32 32 °C, and the pH value is 8.2 8.6 8.6. ?
1.2 test method?
1.2.1 Pro-Bedding Breeding pro-Belgium was collected from the sea near Nantang Town, Yueqing City. In April, it was moved into the outdoor earthen ponds for fattening by means of feeding or changing water. A total of 10kg of pro-Bacillus was raised in an area of ​​0.33 hm?2. In the earthen pond. During the holding period, depending on the water quality, the water is exchanged between 1/4 and 1/3 a day, inoculated with gold algae and Platymonas, and the density of unicellular algae in the water body is maintained. In late June, 5 to 7 days before spawning, the animals were moved to the indoor cement pool for intensive cultivation, aerated, changed water 1/2 to 1/3 daily, and the feeding amount was 150,000 cells/ml. The incubation temperature was 24 to 26°C.
1.2.2 Egg-laying hatching Inspect the development of pro-occlusion gonadal glands. When most of the individual gonads are mature and mature, select 15kg individuals with robust individuals and shell lengths of more than 2.5cm to wash and disinfect, and soak for 10 minutes with (5～10)10-6 KMnO?4. After rinsing and drying, 4 hours later, the pro-beehives were evenly spread on a rectangular spawning bed woven with bamboo strips and placed flat on the bottom of the spawning pool. The spawning bed specifications are 1.5m1.0m. Open the inlet valve and drain valve of the hatching tank, and use the water pump to flush water horizontally into the wall of the inlet, so that the water flows evenly through the egg-laying bed to stimulate the pro-shellfish. After the pro-Bet emission of eggs, lift the egg-laying bed up to about 20cm from the water surface and pick out male individuals in time to reduce excess semen. After the discharge is completed, the egg-laying bed will be removed, the pool water will be filled, and the egg will be left standing for about 30 minutes to settle. Then the upper water will be discharged through the egg-washing drainage hole and the siphon method, and the water will be filled up again, and the egg washing will be repeated twice. Excess semen and dead eggs, etc., to ensure that the hatching water is clean. Open the air valve and adjust the amount of air bubbles and aeration to match the water quality of the hatchery. ?
1.2.3 Cultivation of larvae Before hatchery spawning, the hatching pool is sterilized with 20,000 international units of penicillin and 40,000 international units of streptomycin, then filled with water and inflated. After the egg is washed, the fertilized eggs are transferred to the hatching pond for incubation. The hatching density is controlled at 30-40/ml. When the larvae develop into platter larvae, the juveniles are bred and divided into pools. The upper larvae and lively larvae are further transferred to the sterile water-inoculated culturing tanks with 200 mesh nets, and the culturing density is 5-8/ml. When the larval gut is formed and the digestive organs are well developed, feeds are started. The types of bait are mainly single-celled algae such as Chaetoceros muelleri, Chlorella, Isochrysis galbana, and Forsythium sp. Using forked algae and Isochrysis galbana as the open bait, the daily feeding amount was 20,000 cells/ml. Later, as the individual increases, the amount of feeding gradually increases. When the larvae developed to the shell top stage, Chlorella vulgaris and Platymonas subtilis were added, mixed and fed, and the feeding frequency and feeding amount were appropriately increased depending on the feeding condition of juveniles. When the food is insufficient, it is supplemented with a small amount of active yeast. ?
When the larvae reach the metamorphosis stage, beach mud scraped from the nearby sea area, scraped and screened (with a particle size of 50 to 100 μm) is deposited as an attachment base in the attachment pool, and the mud is spread evenly on the bottom of the pool. , stop inflating. After the precipitation, the small amount of gas is inflated, and the amount of gas is preferably not to stir the sediment. The 300-mesh gill net was used to move the larvae into the attachment pool to increase the amount of water exchange and feed. The daily water exchange rate is 100% to 300%, and the daily feeding amount is maintained at 40,000 to 60,000 cells/ml. After the larvae have developed into juveniles, they are poured once every 5 days. The cultivation density is 800,000 to 1 million/m2. ?
With the development of larvae, the amount of bait was gradually increased, and gold algae, Platymonas and Chlorella were mixed and fed. After the larvae became abnormally attached, the daily feeding amount increased to 50,000-60,000 cells/ml to increase the larvae's demand for various nutrients. ?
Face plate larvae initially added 10 cm of water every day. As the individuals grew, the water was changed 1/2 per day, and the amount of water changed to 2/3 of the day before the shell top changed. After the larvae were transferred to benthic life, the amount of water changed every day was 100% to 300%. ?
2 results?
2.1 Promatite maturity The 2nd to 3rd-age loach selected from the natural sea area 3 months before the nursery was raised and strengthened in an outdoor earth pond, and was continuously observed with the muddy loach collected in the natural sea area, and was raised and maintained. The fertility and gonad maturation of the intensively cultivated pro-family were significantly better than those of pro-shellfish harvested in the natural sea area. ?
2.2 Egg-laying Incubation of dried pro-scallops, after 20 minutes of flowing water stimulation, sperms and eggs are gradually discharged. The male semen is white silky, and the female eggs are gradually discharged from the light yellow smoke. The emission duration is about 40 minutes. The fertility-producing pro-shellfish spawning rate is about 37%, and the average individual egg production is 2.5 million. The hatching density of each pool was controlled at 30-40/ml. Under the conditions of water temperature of 30～32°C and salinity of 24 ‰～26 ,, the first polar body appeared at 9 min of fertilized egg and developed to face plate larvae at 16 h. The average fertilization rate was 98%, and the average hatch rate was 89%. ?
2.3 The larval reared the larvae for about 14 days and developed the eyeballs to the metamorphosis stage. The survival rate of the platter larvae to metamorphosis was 69%, and the adherence rate was 35%. Out of 650 to 950 μm of juveniles, 609,000 grains/m2, juveniles have an area of ​​300 m2, and a total seed production of 180 million grains. ?
3 Discussion and summary?
3.1 Probation and cultivation of pro-shellfish is an important technical link in shellfish breeding. Artificial bait, water change and other measures are adopted. Intensive breeding of pro-scallops is promoted in advance to promote the development of pro-occluded gonads and a large number of high-quality eggs can be obtained. Effective measures for spawning rate and hatching rate. 3.2 Use of spawning beds to mobilize water can prevent water pollution. Use spawning beds to mobilize can adjust the height according to need, pick out male individuals in time, reduce semen in water body, remove pro-bellied one-time, and prevent water pollution. ?
3.3 Use of washing hole and siphon method to remove upper layer of water can avoid damaging eggs. Under the production conditions, using egg washing hole and siphon method to discharge the upper layer of water can also achieve the effect of washing eggs repeatedly. In particular, a large area of ​​breeding requires a large number of fertilized eggs. When using this method, you can avoid egg damage. ?
3.4 The bait is an important factor influencing the development of the larvae. Poor feeding or a single type of bait can cause slow growth of larvae. Individual development is uneven, and due to lack of nutrition, not only the survival rate is low, but also susceptible to disease. All kinds of bait with mixed feeding, keep the density of unicellular algae in the water at any time is an effective measure to improve the survival rate of nursery. ?
3.5 Maintaining fresh water can promote the development of larvae. Muddy larvae have higher water quality requirements, increase exchange of water bodies, reduce the content of organic matter such as baits and feces in water bodies, and promote the growth and development of larvae and increase the survival rate.
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