Freshwater whitefish native to the Amazon River in South America is a large-scale economic fish with both tropical and subtropical food and ornamental values. In 1982, it was introduced into Taiwan by China's Taiwan Province. It was introduced to the mainland in 1983, and subsequent artificial breeding succeeded. However, most of the freshwater whitefish that are hatched by the unit still stay between one ripe and two ripe crops a year. Infrequent hatching in one year is rarely reported. Now we will introduce the key points of the incubating technology of freshwater turtles in one year as follows:
First, broodstock selection
The choice of broodstock is best done before and after November to manage and nurture the winter. Selection criteria: 1 reached the mature age, the fish is robust, high back, body thickness; 2 fast growth; 3 bright body, clear color, body surface without any injury; 4 body weight above 3 kg, body length More than 50 cm, age 4-5 years old.
After the broodstock has been selected, it should be placed in a special pond in a broodstock breeding pond. The cultivation pond requires a water depth of 1.5-2.0 meters deep, an area of ​​400-1200 square meters, and a water temperature of 15 DEG C or more in winter. Stocking density is 2-3 pairs of broodstock per 10m2 (depending on individual size).
Second, broodstock breeding
1. When the temperature of wintering cultivation is above 20 °C, the broodstock can feed normally, and the daily feed is 2%-3% of the fish's weight. Feed consists mainly of artificial pellets containing about 30% of crude protein, which feeds grains and vegetables once every 2-3 days (about 1% of fish's weight); when the water temperature drops to 18-20 °C Feeding can be reduced to about 1% of fish's body weight. When the water temperature is below 17°C, feeds may not be fed. During the winter, if the water is fresh and odor-free, then the fresh water can be properly injected in sunny weather. If the water quality is dirty, change half of the water or one-third of the original pool water in sunny weather. If the weather is cloudy and the water quality is dirty, use the alum water depth of 1 meter and the 0.5 kilogram water solution Quanchiposa.
2. Prenatal strengthening cultivation When the water temperature reaches above 24°C, the feeding amount should be increased and the pelleted feed containing 30% to 40% of protein should be fed. The daily feeding amount accounts for 7%-8% of the broodstock's weight, supplemented by valleys. Buds, vegetables and other feed. About 40 days before hatching of broodstock (that is, beginning in early March), in addition to feeding enough feed, it is also necessary to flush water two times every 3-4 days in the broodstock pool, sooner or later, each time for about 2 hours, prompting them to Gonadal development and maturation, improve oxytocin effect.
Third, artificial labor
1. Pre-production preparation artificial reproduction production is seasonal, time is short and concentrated, and only in the preparation of all aspects of preparation before production, in order to achieve the desired results. 1 Spawning pond and hatching ring. Spawning ponds and ring roads (with square or round shapes) are all fixed facilities, and they are usually hatched at home. Before spawning, the duck tongue mouth and filter yarn must be installed, and strict inspections should be made to prevent obstruction and tearing. 2 oxygenic tools. The tools used for artificial incubation of freshwater pelicans are the same as the commonly used tools for artificial breeding of gems, including broodstock, broodstock, hoppers for eggs, injection tools, and ovipositors. 3 oxytocin. Such as fish pituitary (PG), chorionic hormone (H CG ), ovulation 2 (LRH-A2) and domoxone (D OM ), saline and so on.
2. Selection and mating of broodstock Before freshwater ferret is artificially spawned, the maturity of the broodstock should be checked first. The methods are as follows: 1 Mature male broodstock, the abdomen is flattened, and cloacal cavity is closed in a “1†shape, parallel to the body axis. In the form, light pressure on the abdomen has milky white outflow. 2 mature female brood abdomen is fuller, especially the posterior abdominal enlargement, anal reddish, prominently in the outer cloacal cavity, the ovipositor dig examination, the egg size is uniform, easy to separate with water, shiny, showing green. 3 According to production requirements, 80,000 - 100,000 pieces of eggs per kilogram of females are produced, and 60,000 - 80,000 pieces of fish are produced (normal management). The number of female broodstock is selected from them, and the ratio of male to female is 1:1.2.
3. After the selection of oxytocic agents and injection of broodstock, the broodstock to be produced using the pro-fishing bag is lifted into the spawning pool and cooked with a small amount of drugs. In general, early (before the end of April) or late (from September to October) ) Incubate freshwater white bream with 5 shots of the first pituitary (PG) per female fish (about 4-6 kg/female) and 1-2 shots of the male parent fish; normal spawning season (May-August), each Tail female fish were injected with 20 micrograms of ovulation (L RH - A 2) and 10 micrograms of male fish were injected. The second shot was injected 6-10 hours later. The female fish injected one PG + 20 μg LRH-A 2+2 mg DOM per kilogram, and the male broilers injected 50 μg LRH-A 2+5 mg DOM per tail. The drug was ground into a slurry of 6.5 ‰ of physiological saline. Each broodstock was injected with 1-2 ml of liquid and the base of the pectoral fin was injected. The depth of injection should be 1.2 to 1.5 cm for muscle insertion and 45 degrees to the body of the broodstock.
4. The hatchery management water temperature is 28-30 °C. 7-10 hours after the injection of the second needle, the broodstock begins oestrus. At this point should be 1-2 hours before the broodstock spawning (ie, about 6 hours after the second needle injection) to increase the amount of water in the spawning pool to stimulate broodstock oestrus, ejaculation. When the freshwater white bream bred estrus, the male and female chase and issue a "grilling" sound, about 20-30 minutes to start spawning, ejaculation, the fertilized egg drifts with the pressure of water through the outlet to the egg outside the spawning pool Pool. The fertilized eggs in the egg-sweeping tank are then transported to the loop for transport.
The characteristics of artificial hatching of freshwater pelicans are the high requirements for water temperature and water quality and long incubation time. Under normal circumstances, the temperature of the four major fish hatching is 20-30 °C. The water is non-toxic river water or relatively fresh pond water. The whole incubation time (the water temperature is around 25 °C) only takes 90-96 hours, while the freshwater whitefish require The incubation temperature is 25-30°C, preferably 28-30°C (not to exceed 30°C). The water quality is pollution-free river water. The entire incubation time (water temperature is kept at 28-30°C) also needs 110-120 hours. Because the freshwater white fleas are smaller in size, the fish after the membrane is also smaller (smaller than the mullet), so during the hatching process, on the one hand, the filter yarn is prevented from leaking, and on the other hand, the fertilized egg is broken. After the membrane, the speed of the hatching water flow should be slowed down. It is advisable to keep the eggs or juveniles from sinking to the bottom. It is advisable to flush the surface with water. Otherwise, the fish body will consume too much and affect the emergence rate. When the fish flower grows to three points (two eyes and one waist point), it can be circulated down the road, emerged and sold (or cultivated in its own irrigation pond), and the artificial hatching process is ended.
IV. Postnatal care
First of all, broodstock after artificial oxytocin, more or less some injuries, minor injuries can be used potassium permanganate solution, nitrofurazone ointment, penicillin ointment and other drugs rubbed wounds, severe wounds in addition to rubbing anti-inflammatory drugs at the wound, but also injection Veterinary penicillin, each dose of 3-5 million units, followed by postnatal broodstock into the prepared pool for cultivation (water quality, water level are the same requirements as prenatal training). Re-entering the rearing and brooding rearing of the broodstock. This stage requires the feeding of pelleted feeds containing 30% to 40% protein. The daily feed accounts for about 8% of the fish's body weight, and each time it is voted on in the previous and afternoon, supplemented by grain buds and vegetables, this type of feed accounts for 1 of the fish’s body weight. %about. Postpartum broodstock can be flushed twice a day (in the morning and evening, respectively, lasting about 1 hour) after being cultivated for about 30 days. The broodstock is even washed for half a month to promote gonad development and maturation so as to achieve the second maturation hatch. the goal of.
Five and two ripe hatching
The postpartum broodstock can be examined for the degree of gonadal development after being trained for 45 days. If the female fish has an enlarged lower abdomen and micro-infrared projections of the anus, the oocytes are evenly and easily separable, shiny, and light green when examined by oocyte retrieval. The male-family fish gently press the abdomen with milky semen out of the abdomen, indicating that the batch of broodstock has matured. Engage in the second hatch. The oxytocin method is similar to that of cooked. However, it is better for the female fish to properly increase some pituitary (PG) at the second injection.
Six, three or four ripe hatching
After the broodstock hatched in the second crop, its physical energy consumption was too high, and the mature ovaries in the ovary were very few. At this time eager to engage in three-match hatching, is bound to reach the desired effect, and the water temperature is high, the broodstock damage will be more serious. Therefore, three-matured hatching on the one hand to cultivate good broodstock (as postpartum cultivation and feeding management), on the other hand to master the broodstock maturity, female and broodstock must be abdominal enlargement, anal micro infrared convex. Oocyte retrieval should be performed by the oocyte retrieval device. Eggs are mature and not overripe before they can be used for estrus. Under normal circumstances, the first ripening of freshwater white plover in the southern region is in mid-April, and the second quaternization hatching is conducted in early June. Three-aquaculture hatching can be considered in early September. If broodstock cultivation is indeed good, it should be carried out in late October. Cook hatching.
The key to artificial reproduction of freshwater ferrets is to cultivate good broodstock to ensure that the gonads are basically mature. Once again, hatching water quality must be between 25-30 °C. The hatching rate beyond this range is very low. Therefore, if the natural conditions do not meet the requirements, you should wait for or create conditions, otherwise, it will only waste manpower and affect the rational use of broodstock.
First, broodstock selection
The choice of broodstock is best done before and after November to manage and nurture the winter. Selection criteria: 1 reached the mature age, the fish is robust, high back, body thickness; 2 fast growth; 3 bright body, clear color, body surface without any injury; 4 body weight above 3 kg, body length More than 50 cm, age 4-5 years old.
After the broodstock has been selected, it should be placed in a special pond in a broodstock breeding pond. The cultivation pond requires a water depth of 1.5-2.0 meters deep, an area of ​​400-1200 square meters, and a water temperature of 15 DEG C or more in winter. Stocking density is 2-3 pairs of broodstock per 10m2 (depending on individual size).
Second, broodstock breeding
1. When the temperature of wintering cultivation is above 20 °C, the broodstock can feed normally, and the daily feed is 2%-3% of the fish's weight. Feed consists mainly of artificial pellets containing about 30% of crude protein, which feeds grains and vegetables once every 2-3 days (about 1% of fish's weight); when the water temperature drops to 18-20 °C Feeding can be reduced to about 1% of fish's body weight. When the water temperature is below 17°C, feeds may not be fed. During the winter, if the water is fresh and odor-free, then the fresh water can be properly injected in sunny weather. If the water quality is dirty, change half of the water or one-third of the original pool water in sunny weather. If the weather is cloudy and the water quality is dirty, use the alum water depth of 1 meter and the 0.5 kilogram water solution Quanchiposa.
2. Prenatal strengthening cultivation When the water temperature reaches above 24°C, the feeding amount should be increased and the pelleted feed containing 30% to 40% of protein should be fed. The daily feeding amount accounts for 7%-8% of the broodstock's weight, supplemented by valleys. Buds, vegetables and other feed. About 40 days before hatching of broodstock (that is, beginning in early March), in addition to feeding enough feed, it is also necessary to flush water two times every 3-4 days in the broodstock pool, sooner or later, each time for about 2 hours, prompting them to Gonadal development and maturation, improve oxytocin effect.
Third, artificial labor
1. Pre-production preparation artificial reproduction production is seasonal, time is short and concentrated, and only in the preparation of all aspects of preparation before production, in order to achieve the desired results. 1 Spawning pond and hatching ring. Spawning ponds and ring roads (with square or round shapes) are all fixed facilities, and they are usually hatched at home. Before spawning, the duck tongue mouth and filter yarn must be installed, and strict inspections should be made to prevent obstruction and tearing. 2 oxygenic tools. The tools used for artificial incubation of freshwater pelicans are the same as the commonly used tools for artificial breeding of gems, including broodstock, broodstock, hoppers for eggs, injection tools, and ovipositors. 3 oxytocin. Such as fish pituitary (PG), chorionic hormone (H CG ), ovulation 2 (LRH-A2) and domoxone (D OM ), saline and so on.
2. Selection and mating of broodstock Before freshwater ferret is artificially spawned, the maturity of the broodstock should be checked first. The methods are as follows: 1 Mature male broodstock, the abdomen is flattened, and cloacal cavity is closed in a “1†shape, parallel to the body axis. In the form, light pressure on the abdomen has milky white outflow. 2 mature female brood abdomen is fuller, especially the posterior abdominal enlargement, anal reddish, prominently in the outer cloacal cavity, the ovipositor dig examination, the egg size is uniform, easy to separate with water, shiny, showing green. 3 According to production requirements, 80,000 - 100,000 pieces of eggs per kilogram of females are produced, and 60,000 - 80,000 pieces of fish are produced (normal management). The number of female broodstock is selected from them, and the ratio of male to female is 1:1.2.
3. After the selection of oxytocic agents and injection of broodstock, the broodstock to be produced using the pro-fishing bag is lifted into the spawning pool and cooked with a small amount of drugs. In general, early (before the end of April) or late (from September to October) ) Incubate freshwater white bream with 5 shots of the first pituitary (PG) per female fish (about 4-6 kg/female) and 1-2 shots of the male parent fish; normal spawning season (May-August), each Tail female fish were injected with 20 micrograms of ovulation (L RH - A 2) and 10 micrograms of male fish were injected. The second shot was injected 6-10 hours later. The female fish injected one PG + 20 μg LRH-A 2+2 mg DOM per kilogram, and the male broilers injected 50 μg LRH-A 2+5 mg DOM per tail. The drug was ground into a slurry of 6.5 ‰ of physiological saline. Each broodstock was injected with 1-2 ml of liquid and the base of the pectoral fin was injected. The depth of injection should be 1.2 to 1.5 cm for muscle insertion and 45 degrees to the body of the broodstock.
4. The hatchery management water temperature is 28-30 °C. 7-10 hours after the injection of the second needle, the broodstock begins oestrus. At this point should be 1-2 hours before the broodstock spawning (ie, about 6 hours after the second needle injection) to increase the amount of water in the spawning pool to stimulate broodstock oestrus, ejaculation. When the freshwater white bream bred estrus, the male and female chase and issue a "grilling" sound, about 20-30 minutes to start spawning, ejaculation, the fertilized egg drifts with the pressure of water through the outlet to the egg outside the spawning pool Pool. The fertilized eggs in the egg-sweeping tank are then transported to the loop for transport.
The characteristics of artificial hatching of freshwater pelicans are the high requirements for water temperature and water quality and long incubation time. Under normal circumstances, the temperature of the four major fish hatching is 20-30 °C. The water is non-toxic river water or relatively fresh pond water. The whole incubation time (the water temperature is around 25 °C) only takes 90-96 hours, while the freshwater whitefish require The incubation temperature is 25-30°C, preferably 28-30°C (not to exceed 30°C). The water quality is pollution-free river water. The entire incubation time (water temperature is kept at 28-30°C) also needs 110-120 hours. Because the freshwater white fleas are smaller in size, the fish after the membrane is also smaller (smaller than the mullet), so during the hatching process, on the one hand, the filter yarn is prevented from leaking, and on the other hand, the fertilized egg is broken. After the membrane, the speed of the hatching water flow should be slowed down. It is advisable to keep the eggs or juveniles from sinking to the bottom. It is advisable to flush the surface with water. Otherwise, the fish body will consume too much and affect the emergence rate. When the fish flower grows to three points (two eyes and one waist point), it can be circulated down the road, emerged and sold (or cultivated in its own irrigation pond), and the artificial hatching process is ended.
IV. Postnatal care
First of all, broodstock after artificial oxytocin, more or less some injuries, minor injuries can be used potassium permanganate solution, nitrofurazone ointment, penicillin ointment and other drugs rubbed wounds, severe wounds in addition to rubbing anti-inflammatory drugs at the wound, but also injection Veterinary penicillin, each dose of 3-5 million units, followed by postnatal broodstock into the prepared pool for cultivation (water quality, water level are the same requirements as prenatal training). Re-entering the rearing and brooding rearing of the broodstock. This stage requires the feeding of pelleted feeds containing 30% to 40% protein. The daily feed accounts for about 8% of the fish's body weight, and each time it is voted on in the previous and afternoon, supplemented by grain buds and vegetables, this type of feed accounts for 1 of the fish’s body weight. %about. Postpartum broodstock can be flushed twice a day (in the morning and evening, respectively, lasting about 1 hour) after being cultivated for about 30 days. The broodstock is even washed for half a month to promote gonad development and maturation so as to achieve the second maturation hatch. the goal of.
Five and two ripe hatching
The postpartum broodstock can be examined for the degree of gonadal development after being trained for 45 days. If the female fish has an enlarged lower abdomen and micro-infrared projections of the anus, the oocytes are evenly and easily separable, shiny, and light green when examined by oocyte retrieval. The male-family fish gently press the abdomen with milky semen out of the abdomen, indicating that the batch of broodstock has matured. Engage in the second hatch. The oxytocin method is similar to that of cooked. However, it is better for the female fish to properly increase some pituitary (PG) at the second injection.
Six, three or four ripe hatching
After the broodstock hatched in the second crop, its physical energy consumption was too high, and the mature ovaries in the ovary were very few. At this time eager to engage in three-match hatching, is bound to reach the desired effect, and the water temperature is high, the broodstock damage will be more serious. Therefore, three-matured hatching on the one hand to cultivate good broodstock (as postpartum cultivation and feeding management), on the other hand to master the broodstock maturity, female and broodstock must be abdominal enlargement, anal micro infrared convex. Oocyte retrieval should be performed by the oocyte retrieval device. Eggs are mature and not overripe before they can be used for estrus. Under normal circumstances, the first ripening of freshwater white plover in the southern region is in mid-April, and the second quaternization hatching is conducted in early June. Three-aquaculture hatching can be considered in early September. If broodstock cultivation is indeed good, it should be carried out in late October. Cook hatching.
The key to artificial reproduction of freshwater ferrets is to cultivate good broodstock to ensure that the gonads are basically mature. Once again, hatching water quality must be between 25-30 °C. The hatching rate beyond this range is very low. Therefore, if the natural conditions do not meet the requirements, you should wait for or create conditions, otherwise, it will only waste manpower and affect the rational use of broodstock.
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