1. The source of broodstock and the source of broodstock cultivation are two: one is the natural fishing of broodstock; the second is the artificial breeding of broodstock. Whether natural or artificially cultivated broodstock, females are required to be over 50 cm in length and 4 to 5 years of age; males are over 40 cm in length and older than 3 years of age. Feeding of natural broodstock: Natural broodstock is rich in germplasm, but it is difficult to eat natural broodstock, and some brooders die of hunger because they do not eat. Therefore, we must think of ways to make it eat as early as possible. The more effective method is to tie the bait or hook it with a thin wire. Near the head of the broodstock, simulate the live fish to induce it to feed; you can also use the water flow in the inlet to make the bait slowly move, and then rely on the swing of the bait. It feeds; or it is fed along with the broodstock that has started feeding to drive its feeding. Baits: Baits for broodstock cultivation include sardines, squid, jadefish, saury, and horse mackerel. No matter what kind of fish, as long as its low fat content, good freshness, broodstock can eat. In the diet can be added a suitable amount of vitamin E, C and multivitamin preparations and other nutrients, in order to help improve the quality of eggs, the amount added to the total amount of 1% -2%. Feeding amount is 1% - 3% of the fish's body weight, and it is usually fed 1-2 times a day. Water quality: The broodstock cultivation generally uses filtered seawater. The pool should be kept clean and the residual baits and dirt should be removed in time. Water temperature is maintained at 14-16°C, salinity is 28-35°F, pH is 7.7-8.6, dissolved oxygen is above 6.0 mg/l, and light control is between 1000-5000 lx. Broodstock stocking density: According to water quality, it is generally 1-2 tail/m2. 2. The male and female identification of spawning and fertilized gums can be judged from the gonads: In the breeding period, the reproductive hole is red and the round is female, and the slender and non-redden are male. Artificially cultivated broodstocks can naturally spawn. Prior to spawning, males chase females and induce females to spawn. Spawning time is usually before 9 o'clock in the evening, and spawning is usually stopped after midnight. Naturally produced eggs floated on the surface after fertilization. 3. Collection of fertilized eggs and hatching of broodstock When the broodstock naturally spawn in the spawning pool, place a cage in a cage with an 80-mesh sieve at the outlet of the spawning pond. The cage was placed in the bucket, excess water overflowed from the bucket, and the eggs were left in the cage. Because of the large amount of impurities in the spawning pool water, it is better to remove the coarser impurities by hand-gripping the net to keep the water quality clean during hatching. Then stop running water and let stand for a period of time. After the dead eggs and the bad eggs sink, collect the eggs floating on them, rinse them with clean seawater, and incubate them in the incubator. Ginger eggs hatching water temperature is 10-24 °C, the optimum water temperature is 14-16 °C, the appropriate salinity for hatching is 28‰-33‰. The hatching method is relatively simple. It can be used for hatching cages or hatching sinks, and can also be hatched directly in the nursery ponds. The former is generally 10-50 million grains per square meter, and the latter is generally 1-40 thousand grains per square meter. During the incubation process, the eggs that died were white and sinking. Therefore, the dead eggs that sink to the bottom should be sucked out every day, and an appropriate amount of fresh water should be added to make the waterproof material worse. It is best to inflate during the incubation process, but stop the inflation during the suction process so that dirt and dead eggs will sink.
Dietary supplement
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